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Domestication is a sustained multi-generational relationship in which humans assume a significant degree of control over the
reproduction Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. Reproduction is a fundamental feature of all known life; each individual or ...
and care of another group of organisms to secure a more predictable supply of resources from that group. A broader biological definition is that it is a coevolutionary process that arises from a mutualism, in which one species (the domesticator) constructs an environment where it actively manages both the survival and reproduction of another species (the domesticate) in order to provide the former with resources and/or services. The domestication of plants and animals by humans was a major cultural innovation ranked in importance with the conquest of fire, the manufacturing of tools, and the development of verbal language.
Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...
recognized the small number of traits that made domestic species different from their wild ancestors. He was also the first to recognize the difference between conscious
selective breeding Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant m ...
(i.e. artificial selection) in which humans directly select for desirable traits, and unconscious selection where traits evolve as a by-product of
natural selection Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charl ...
or from selection on other traits. There is a genetic difference between domestic and wild populations. There is also such a difference between the domestication traits that researchers believe to have been essential at the early stages of domestication, and the improvement traits that have appeared since the split between wild and domestic populations. Domestication traits are generally fixed within all domesticates, and were selected during the initial episode of domestication of that animal or plant, whereas improvement traits are present only in a proportion of domesticates, though they may be fixed in individual breeds or regional populations. The
dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relative. ...
was the first domesticated
species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...
, and was established across
Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago ...
before the end of the
Late Pleistocene The Late Pleistocene is an unofficial age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a stratigraphic perspective. It is intended to be the fourth division of the Pleistocene Epoch within ...
era, well before cultivation and before the domestication of other animals. The archaeological and genetic data suggest that long-term bidirectional
gene flow In population genetics, gene flow (also known as gene migration or geneflow and allele flow) is the transfer of genetic material from one population to another. If the rate of gene flow is high enough, then two populations will have equivalent a ...
between wild and domestic stocks – including
donkey The domestic donkey is a hoofed mammal in the family Equidae, the same family as the horse. It derives from the African wild ass, ''Equus africanus'', and may be classified either as a subspecies thereof, ''Equus africanus asinus'', or as a ...
s,
horses The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million yea ...
, New and Old World
camelid Camelids are members of the biological family Camelidae, the only currently living family in the suborder Tylopoda. The seven extant members of this group are: dromedary camels, Bactrian camels, wild Bactrian camels, llamas, alpacas, vicuñas, ...
s,
goat The goat or domestic goat (''Capra hircus'') is a domesticated species of goat-antelope typically kept as livestock. It was domesticated from the wild goat (''C. aegagrus'') of Southwest Asia and Eastern Europe. The goat is a member of the a ...
s,
sheep Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus ''Ovis'', in everyday usage it almost always refers to domesticated sh ...
, and
pig The pig (''Sus domesticus''), often called swine, hog, or domestic pig when distinguishing from other members of the genus '' Sus'', is an omnivorous, domesticated, even-toed, hoofed mammal. It is variously considered a subspecies of ''Sus s ...
s – was common. Given its importance to humans and its value as a model of
evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
ary and
demographic Demography () is the statistical study of populations, especially human beings. Demographic analysis examines and measures the dimensions and dynamics of populations; it can cover whole societies or groups defined by criteria such as ed ...
change, domestication has attracted scientists from
archaeology Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscape ...
,
paleontology Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of foss ...
,
anthropology Anthropology is the scientific study of humanity, concerned with human behavior, human biology, cultures, societies, and linguistics, in both the present and past, including past human species. Social anthropology studies patterns of behavi ...
,
botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek w ...
,
zoology Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and dis ...
,
genetics Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar working i ...
, and the
environmental sciences Environmental science is an interdisciplinary academic field that integrates physics, biology, and geography (including ecology, chemistry, plant science, zoology, mineralogy, oceanography, limnology, soil science, geology and physical geograp ...
. Among
birds Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight ...
, the major domestic species today is the chicken, important for meat and eggs, though economically valuable poultry include the
turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a transcontinental country located mainly on the Anatolian Peninsula in Western Asia, with a small portion on the Balkan Peninsula in ...
,
guineafowl Guineafowl (; sometimes called "pet speckled hens" or "original fowl") are birds of the family Numididae in the order Galliformes. They are endemic to Africa and rank among the oldest of the gallinaceous birds. Phylogenetically, they branched ...
and numerous other species. Birds are also widely kept as
cagebirds Aviculture is the practice of keeping and breeding birds, especially of wild birds in captivity. Types There are various reasons that people get involved in aviculture. Some people breed birds to preserve a species. Some people breed parrots ...
, from
songbirds A songbird is a bird belonging to the suborder Passeri of the perching birds (Passeriformes). Another name that is sometimes seen as the scientific or vernacular name is Oscines, from Latin ''oscen'', "songbird". The Passeriformes contains 5000 ...
to
parrots Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genera comprising the order Psittaciformes (), found mostly in tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittacoid ...
. The longest established
invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
domesticates are the
honey bee A honey bee (also spelled honeybee) is a eusocial flying insect within the genus ''Apis'' of the bee clade, all native to Afro-Eurasia. After bees spread naturally throughout Africa and Eurasia, humans became responsible for the current cosmop ...
and the silkworm.
Land snail A land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails. ''Land snail'' is the common name for terrestrial gastropod mollusks that have shells (those without shells are known as ...
s are raised for food, while species from several phyla are kept for research, and others are bred for
biological control Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also invo ...
. The domestication of plants began at least 12,000 years ago with
cereal A cereal is any grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, germ, and bran. Cereal grain crops are grown in greater quantities and provide more food e ...
s in the
Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europea ...
, and the
bottle gourd Calabash (; ''Lagenaria siceraria''), also known as bottle gourd, white-flowered gourd, long melon, birdhouse gourd, New Guinea bean, Tasmania bean, and opo squash, is a vine grown for its fruit. It can be either harvested young to be consumed ...
in Asia. Agriculture developed in at least 11 different centres around the world, domesticating different crops and animals.


Overview

Domestication, from the
Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
', 'belonging to the house', is "a sustained multi-generational, mutualistic relationship in which one
organism In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells ( cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fung ...
assumes a significant degree of influence over the
reproduction Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. Reproduction is a fundamental feature of all known life; each individual or ...
and care of another organism in order to secure a more predictable supply of a resource of interest, and through which the partner organism gains advantage over individuals that remain outside this relationship, thereby benefitting and often increasing the fitness of both the domesticator and the target domesticate." Another related definition is that domestication "is a coevolutionary process that arises from a mutualism, in which one species (the domesticator) constructs an environment where it actively manages both the survival and reproduction of another species (the domesticate) in order to provide the former with resources and/or services. This allows for increased fitness for the interacting organisms within the mutualistic relationship, leading to the evolution of traits that ensures the stable association of domesticator and domesticate across generations." These definitions recognize both the biological and the cultural components of the human-associated domestication process and the impacts on both humans and the domesticated animals and plants. All past definitions of domestication have included a relationship between humans with plants and animals, but their differences lay in who was considered as the lead partner in the relationship. These new definitions recognize a mutualistic relationship in which both partners gain benefits. Domestication has vastly enhanced the reproductive output of crop plants, livestock, and pets far beyond that of their wild progenitors. Domesticates have provided humans with resources that they could more predictably and securely control, move, and redistribute, which has been the advantage that had fueled a population explosion of the agro-pastoralists and their spread to all corners of the planet.
Houseplant A houseplant, sometimes known as a pot plant, potted plant, or an indoor plant, is an ornamental plant that is grown indoors. As such, they are found in places like residences and offices, mainly for decorative purposes. Common houseplants are us ...
s and ornamentals are plants domesticated primarily for
aesthetic Aesthetics, or esthetics, is a branch of philosophy that deals with the nature of beauty and taste, as well as the philosophy of art (its own area of philosophy that comes out of aesthetics). It examines aesthetic values, often expressed th ...
enjoyment in and around the home, while those domesticated for large-scale food production are called crops. Domesticated plants deliberately altered or selected for special desirable characteristics are cultigens. Animals domesticated for home companionship are called
pet A pet, or companion animal, is an animal kept primarily for a person's company or entertainment rather than as a working animal, livestock, or a laboratory animal. Popular pets are often considered to have attractive appearances, intelligence, ...
s, while those domesticated for food or work are known as
livestock Livestock are the Domestication, domesticated animals raised in an agriculture, agricultural setting to provide labor and produce diversified products for consumption such as meat, egg as food, eggs, milk, fur, leather, and wool. The term is som ...
. This biological mutualism is not restricted to humans with domestic crops and livestock but is well-documented in nonhuman species, especially among a number of social insect domesticators and their plant and animal domesticates, for example the
ant–fungus mutualism The ant–fungus mutualism is a symbiosis seen between certain ant and fungal species, in which ants actively cultivate fungus much like humans farm crops as a food source. There is only evidence of two instances in which this form of agriculture ...
that exists between
leafcutter ants Leafcutter ants, a non-generic name, are any of 47 species of leaf-chewing ants belonging to the two genera ''Atta'' and '' Acromyrmex''. These species of tropical, fungus-growing ants are all endemic to South and Central America, Mexico, and par ...
and certain fungi.
Domestication syndrome Domestication syndrome refers to two sets of phenotypic traits that are common to either domesticated animals, or domesticated plants. These traits were identified by Charles Darwin in '' The Variation of Animals and Plants Under Domestication ...
is the suite of
phenotypic In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological prope ...
traits arising during domestication that distinguish crops from their wild ancestors. The term is also applied to vertebrate animals, and includes increased docility and tameness, coat color changes, reductions in tooth size, changes in craniofacial morphology, alterations in ear and tail form (e.g., floppy ears), more frequent and no seasonal estrus cycles, alterations in
adrenocorticotropic hormone Adrenocorticotropic hormone (ACTH; also adrenocorticotropin, corticotropin) is a polypeptide tropic hormone produced by and secreted by the anterior pituitary gland. It is also used as a medication and diagnostic agent. ACTH is an important co ...
levels, changed concentrations of several neurotransmitters, prolongations in juvenile behavior, and reductions in both total brain size and of particular brain regions.


History


Cause and timing

The
domestication of animals The domestication of animals is the mutual relationship between non-human animals and the humans who have influence on their care and reproduction. Charles Darwin recognized a small number of traits that made domesticated species different from ...
and plants was triggered by the climatic and environmental changes that occurred after the peak of the
Last Glacial Maximum The Last Glacial Maximum (LGM), also referred to as the Late Glacial Maximum, was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent. Ice sheets covered much of Northern North America, Northern Eur ...
around 21,000 years ago and which continue to this present day. These changes made obtaining food difficult. The first domesticate was the
wolf The wolf (''Canis lupus''; : wolves), also known as the gray wolf or grey wolf, is a large canine native to Eurasia and North America. More than thirty subspecies of ''Canis lupus'' have been recognized, and gray wolves, as popularly u ...
(''Canis lupus'') at least 15,000 years ago. The
Younger Dryas The Younger Dryas (c. 12,900 to 11,700 years BP) was a return to glacial conditions which temporarily reversed the gradual climatic warming after the Last Glacial Maximum (LGM, c. 27,000 to 20,000 years BP). The Younger Dryas was the last stage ...
that occurred 12,900 years ago was a period of intense cold and aridity that put pressure on humans to intensify their foraging strategies. By the beginning of the Holocene from 11,700 years ago, favorable climatic conditions and increasing human populations led to small-scale animal and plant domestication, which allowed humans to augment the food that they were obtaining through hunter-gathering. The Neolithic transition led to agricultural societies emerging in locations across Eurasia, North Africa, and South and Central America. In the
Fertile Crescent The Fertile Crescent ( ar, الهلال الخصيب) is a crescent-shaped region in the Middle East, spanning modern-day Iraq, Syria, Lebanon, Israel, Palestine and Jordan, together with the northern region of Kuwait, southeastern region of ...
10,000-11,000 years ago,
zooarchaeology Zooarchaeology (sometimes called archaeozoology), also known as faunal analysis, is a branch of archaeology that studies remains of animals from archaeological sites. Faunal remains are the items left behind when an animal dies. These include bon ...
indicates that goats, pigs, sheep, and
taurine cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Adult females are referred to as cows and adult ma ...
were the first livestock to be domesticated. Two thousand years later, humped
zebu The zebu (; ''Bos indicus'' or ''Bos taurus indicus''), sometimes known in the plural as indicine cattle or humped cattle, is a species or subspecies of domestic cattle originating in the Indian sub-continent. Zebu are characterised by a fatty h ...
cattle were domesticated in what is today
Baluchistan Balochistan ( ; bal, بلۏچستان; also romanised as Baluchistan and Baluchestan) is a historical region in Western and South Asia, located in the Iranian plateau's far southeast and bordering the Indian Plate and the Arabian Sea coastline. ...
in Pakistan. In
East Asia East Asia is the eastern region of Asia, which is defined in both geographical and ethno-cultural terms. The modern states of East Asia include China, Japan, Mongolia, North Korea, South Korea, and Taiwan. China, North Korea, South Korea and ...
8,000 years ago, pigs were domesticated from wild boar that were genetically different from those found in the Fertile Crescent. The horse was domesticated on the Central Asian steppe 5,500 years ago. Both the chicken in Southeast Asia and the cat in Egypt were domesticated 4,000 years ago. The sudden appearance of the
domestic dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relative. D ...
(''Canis lupus familiaris'') in the archaeological record then led to a rapid shift in the
evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
,
ecology Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps w ...
, and demography of both humans and numerous species of animals and plants. It was followed by livestock and crop domestication, and the transition of humans from foraging to farming in different places and times across the planet. Around 10,000 YBP, a new way of life emerged for humans through the management and exploitation of plant and animal species, leading to higher-density populations in the centers of domestication, the expansion of agricultural economies, and the development of urban communities.


Animals


Theory

The domestication of animals is the relationship between non-human animals and humans who have influence on their "care" and reproduction.
Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...
recognized the small number of traits that made domestic species different from their wild ancestors. He was also the first to recognize the difference between conscious
selective breeding Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant m ...
in which humans directly select for desirable traits, and unconscious selection where traits evolve as a by-product of
natural selection Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charl ...
or from selection on other traits. There is a difference between domestic and wild populations, though studies suggest domestication as a form of survival for most animals under human care. There is also such a difference between the domestication traits that researchers believe to have been essential at the early stages of domestication, and the improvement traits that have appeared since the split between wild and domestic populations. Domestication traits are generally fixed within all domesticates, and were selected during the initial episode of domestication of that animal or plant, whereas improvement traits are present only in a proportion of domesticates, though they may be fixed in individual breeds or regional populations. ''Domestication'' of animals should not be confused with ''taming''. Taming is the conditioned behavioral modification of an individual animal, to reduce its natural avoidance of humans, and to tolerate the presence of humans. Domestication is the permanent genetic modification of a bred lineage that leads to an inherited predisposition to respond calmly to human presence. Certain animal species, and certain individuals within those species, make better candidates for domestication merely for their inability to defend themselves. These animals exhibit certain behavioral characteristics: # The size and organization of their social structure # The availability and the degree of selectivity in their choice of mates # The ease and speed with which the parents bond with their young, and the maturity and mobility of the young at birth # The degree of flexibility in diet and habitat tolerance; and # Responses to humans and new environments, including reduced flight response and reactivity to external stimuli.


Mammals

The beginnings of animal domestication involved a protracted
coevolution In biology, coevolution occurs when two or more species reciprocally affect each other's evolution through the process of natural selection. The term sometimes is used for two traits in the same species affecting each other's evolution, as well ...
ary process with multiple stages along different pathways. There are three proposed major pathways that most animal domesticates followed into domestication: #
commensals Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit fro ...
, adapted to a human niche (e.g.,
dogs The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relative. ...
,
cats The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of t ...
, possibly
pigs The pig (''Sus domesticus''), often called swine, hog, or domestic pig when distinguishing from other members of the genus '' Sus'', is an omnivorous, domesticated, even-toed, hoofed mammal. It is variously considered a subspecies of ''Sus s ...
); # prey animals sought for food (e.g.,
sheep Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus ''Ovis'', in everyday usage it almost always refers to domesticated sh ...
,
goats The goat or domestic goat (''Capra hircus'') is a domesticated species of goat-antelope typically kept as livestock. It was domesticated from the wild goat (''C. aegagrus'') of Southwest Asia and Eastern Europe. The goat is a member of the a ...
,
cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult ma ...
,
water buffalo The water buffalo (''Bubalus bubalis''), also called the domestic water buffalo or Asian water buffalo, is a large bovid originating in the Indian subcontinent and Southeast Asia. Today, it is also found in Europe, Australia, North America, So ...
,
yak The domestic yak (''Bos grunniens''), also known as the Tartary ox, grunting ox or hairy cattle, is a species of long-haired domesticated cattle found throughout the Himalayan region of the Indian subcontinent, the Tibetan Plateau, Kachin Sta ...
, pig, reindeer,
llama The llama (; ) (''Lama glama'') is a domesticated South American camelid, widely used as a List of meat animals, meat and pack animal by Inca empire, Andean cultures since the Pre-Columbian era. Llamas are social animals and live with othe ...
and
alpaca The alpaca (''Lama pacos'') is a species of South American camelid mammal. It is similar to, and often confused with, the llama. However, alpacas are often noticeably smaller than llamas. The two animals are closely related and can successf ...
); and # animals targeted for draft and non-food resources (e.g.,
horse The horse (''Equus ferus caballus'') is a Domestication, domesticated, odd-toed ungulate, one-toed, ungulate, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two Extant taxon, extant subspecies of wild horse, ''Equus fer ...
,
donkey The domestic donkey is a hoofed mammal in the family Equidae, the same family as the horse. It derives from the African wild ass, ''Equus africanus'', and may be classified either as a subspecies thereof, ''Equus africanus asinus'', or as a ...
,
camel A camel (from: la, camelus and grc-gre, κάμηλος (''kamēlos'') from Hebrew or Phoenician: גָמָל ''gāmāl''.) is an even-toed ungulate in the genus ''Camelus'' that bears distinctive fatty deposits known as "humps" on its back. C ...
). The dog was the first domesticant, and was established across
Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago ...
before the end of the
Late Pleistocene The Late Pleistocene is an unofficial age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a stratigraphic perspective. It is intended to be the fourth division of the Pleistocene Epoch within ...
era, well before cultivation and before the domestication of other animals. Humans did not intend to domesticate animals from either the commensal or prey pathways, or at least they did not envision a domesticated animal would result from it. In both of those cases, humans became entangled with these species as the relationship between them intensified, and humans' role in their survival and reproduction led gradually to formalised
animal husbandry Animal husbandry is the branch of agriculture concerned with animals that are raised for meat, fibre, milk, or other products. It includes day-to-day care, selective breeding, and the raising of livestock. Husbandry has a long history, startin ...
. Although the directed pathway proceeded from capture to taming, the other two pathways are not as goal-oriented, and archaeological records suggest that they took place over much longer time frames. Unlike other domestic species which were primarily selected for production-related traits, dogs were initially selected for their behaviors. The archaeological and genetic data suggest that long-term bidirectional
gene flow In population genetics, gene flow (also known as gene migration or geneflow and allele flow) is the transfer of genetic material from one population to another. If the rate of gene flow is high enough, then two populations will have equivalent a ...
between wild and domestic stocks – including
donkey The domestic donkey is a hoofed mammal in the family Equidae, the same family as the horse. It derives from the African wild ass, ''Equus africanus'', and may be classified either as a subspecies thereof, ''Equus africanus asinus'', or as a ...
s,
horse The horse (''Equus ferus caballus'') is a Domestication, domesticated, odd-toed ungulate, one-toed, ungulate, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two Extant taxon, extant subspecies of wild horse, ''Equus fer ...
s, New and Old World
camelid Camelids are members of the biological family Camelidae, the only currently living family in the suborder Tylopoda. The seven extant members of this group are: dromedary camels, Bactrian camels, wild Bactrian camels, llamas, alpacas, vicuñas, ...
s,
goat The goat or domestic goat (''Capra hircus'') is a domesticated species of goat-antelope typically kept as livestock. It was domesticated from the wild goat (''C. aegagrus'') of Southwest Asia and Eastern Europe. The goat is a member of the a ...
s,
sheep Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus ''Ovis'', in everyday usage it almost always refers to domesticated sh ...
, and
pig The pig (''Sus domesticus''), often called swine, hog, or domestic pig when distinguishing from other members of the genus '' Sus'', is an omnivorous, domesticated, even-toed, hoofed mammal. It is variously considered a subspecies of ''Sus s ...
s – was common. One study has concluded that human selection for domestic traits likely counteracted the homogenizing effect of gene flow from wild boars into pigs and created
domestication islands Domestication islands refers to regions within DNA that do not change despite gene flow between wild and domesticated species. Speciation islands In 2005, a study of genomic DNA within species of mosquitoes found that there were "speciation island ...
in the genome. The same process may also apply to other domesticated animals.


Birds

Domesticated birds principally mean poultry, raised for meat and eggs: some
Galliformes Galliformes is an order of heavy-bodied ground-feeding birds that includes turkeys, chickens, quail, and other landfowl. Gallinaceous birds, as they are called, are important in their ecosystems as seed dispersers and predators, and are ofte ...
( chicken,
turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a transcontinental country located mainly on the Anatolian Peninsula in Western Asia, with a small portion on the Balkan Peninsula in ...
,
guineafowl Guineafowl (; sometimes called "pet speckled hens" or "original fowl") are birds of the family Numididae in the order Galliformes. They are endemic to Africa and rank among the oldest of the gallinaceous birds. Phylogenetically, they branched ...
) and
Anseriformes Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest family, which i ...
(waterfowl:
duck Duck is the common name for numerous species of waterfowl in the family Anatidae. Ducks are generally smaller and shorter-necked than swans and geese, which are members of the same family. Divided among several subfamilies, they are a form ta ...
,
goose A goose ( : geese) is a bird of any of several waterfowl species in the family Anatidae. This group comprises the genera ''Anser'' (the grey geese and white geese) and '' Branta'' (the black geese). Some other birds, mostly related to the she ...
,
swan Swans are birds of the family Anatidae within the genus ''Cygnus''. The swans' closest relatives include the geese and ducks. Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe Cygnini. Someti ...
). Also widely domesticated are
cagebirds Aviculture is the practice of keeping and breeding birds, especially of wild birds in captivity. Types There are various reasons that people get involved in aviculture. Some people breed birds to preserve a species. Some people breed parrots ...
such as
songbirds A songbird is a bird belonging to the suborder Passeri of the perching birds (Passeriformes). Another name that is sometimes seen as the scientific or vernacular name is Oscines, from Latin ''oscen'', "songbird". The Passeriformes contains 5000 ...
and
parrots Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genera comprising the order Psittaciformes (), found mostly in tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittacoid ...
; these are kept both for pleasure and for use in research. The
domestic pigeon The domestic pigeon (''Columba livia domestica'' or ''Columba livia'' ''forma'' ''domestica'') is a pigeon subspecies that was derived from the rock dove (also called the rock pigeon). The rock pigeon is the world's oldest domesticated bird. Me ...
has been used both for food and as a means of communication between far-flung places through the exploitation of the pigeon's homing instinct; research suggests it was domesticated as early as 10,000 years ago. Chicken fossils in China were dated 7,400 years ago. The chicken's wild ancestor is ''
Gallus gallus The red junglefowl (''Gallus gallus'') is a tropical bird in the family Phasianidae. It ranges across much of Southeast Asia and parts of South Asia. It was formerly known as the Bankiva or Bankiva Fowl. It is the species that gave rise to the ...
'', the red junglefowl of Southeast Asia. It appears to have been kept initially for
cockfighting A cockfight is a blood sport, held in a ring called a cockpit. The history of raising fowl for fighting goes back 6,000 years. The first documented use of the ''word'' gamecock, denoting use of the cock as to a "game", a sport, pastime or ente ...
rather than for food.


Invertebrates

Two
insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of ...
s, the silkworm and the
western honey bee The western honey bee or European honey bee (''Apis mellifera'') is the most common of the 7–12 species of honey bees worldwide. The genus name ''Apis'' is Latin for "bee", and ''mellifera'' is the Latin for "honey-bearing" or "honey carrying" ...
, have been domesticated for over 5,000 years, often for commercial use. The silkworm is raised for the silk threads wound around its
pupa A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their ...
l cocoon; the western honey bee, for
honey Honey is a sweet and viscous substance made by several bees, the best-known of which are honey bees. Honey is made and stored to nourish bee colonies. Bees produce honey by gathering and then refining the sugary secretions of plants (primaril ...
, and, lately, for
pollination Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, a ...
of crops. Several other invertebrates have been domesticated, both terrestrial and aquatic, including some such as ''
Drosophila melanogaster ''Drosophila melanogaster'' is a species of fly (the taxonomic order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the "vinegar fly" or "pomace fly". Starting with Ch ...
'' fruit flies and the freshwater cnidarian '' Hydra'' for research into genetics and physiology. Few have a long history of domestication. Most are used for food or other products such as
shellac Shellac () is a resin secreted by the female lac bug on trees in the forests of India and Thailand. It is processed and sold as dry flakes and dissolved in alcohol to make liquid shellac, which is used as a brush-on colorant, food glaze and w ...
and
cochineal The cochineal ( , ; ''Dactylopius coccus'') is a scale insect in the suborder Sternorrhyncha, from which the natural dye carmine is derived. A primarily sessile parasite native to tropical and subtropical South America through North America ...
. The phyla involved are
Cnidaria Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature is cnidocytes, specialized cells that th ...
,
Platyhelminthes The flatworms, flat worms, Platyhelminthes, or platyhelminths (from the Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") are a phylum of relatively simple bilaterian, unsegment ...
(for
biological control Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also invo ...
), Annelida,
Mollusca Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estim ...
,
Arthropoda Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and cuticle made of chitin, oft ...
(marine
crustacea Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
ns as well as insects and spiders), and
Echinodermata An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea l ...
. While many marine molluscs are used for food, only a few have been domesticated, including
squid True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...
,
cuttlefish Cuttlefish or cuttles are marine molluscs of the order Sepiida. They belong to the class Cephalopoda which also includes squid, octopuses, and nautiluses. Cuttlefish have a unique internal shell, the cuttlebone, which is used for control o ...
and
octopus An octopus ( : octopuses or octopodes, see below for variants) is a soft-bodied, eight- limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlef ...
, all used in research on
behaviour Behavior (American English) or behaviour (British English) is the range of actions and mannerisms made by individuals, organisms, systems or artificial entities in some environment. These systems can include other systems or organisms as wel ...
and
neurology Neurology (from el, νεῦρον (neûron), "string, nerve" and the suffix -logia, "study of") is the branch of medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the brain, the spinal ...
. Terrestrial snails in the genera ''
Helix A helix () is a shape like a corkscrew or spiral staircase. It is a type of smooth space curve with tangent lines at a constant angle to a fixed axis. Helices are important in biology, as the DNA molecule is formed as two intertwined helices ...
'' and ''
Murex ''Murex'' is a genus of medium to large sized predatory tropical sea snails. These are carnivorous marine gastropod molluscs in the family Muricidae, commonly called "murexes" or "rock snails".Houart, R.; Gofas, S. (2010). Murex Linnaeus, 1758 ...
'' are raised for food. Several parasitic or parasitoidal insects including the fly '' Eucelatoria'', the beetle '' Chrysolina'', and the wasp ''
Aphytis Aphytis ( grc, Ἄφυτις), also Aphyte (Ἀφύτη) and Aphytus or Aphytos (Ἄφυτος), was an ancient Greek city in Pallene, the westernmost headland of Chalcidice. Around the middle of the 8th century BC colonists from Euboea arrived. ...
'' are raised for biological control. Conscious or unconscious artificial selection has many effects on species under domestication; variability can readily be lost by inbreeding, selection against undesired traits, or genetic drift, while in ''Drosophila'', variability in eclosion time (when adults emerge) has increased.


Plants

The initial domestication of animals impacted most on the genes that controlled their behavior, but the initial domestication of plants impacted most on the genes that controlled their morphology (seed size, plant architecture, dispersal mechanisms) and their physiology (timing of germination or ripening). The domestication of
wheat Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeological ...
provides an example. Wild wheat shatters and falls to the ground to reseed itself when ripe, but domesticated wheat stays on the stem for easier harvesting. This change was possible because of a random mutation in the wild populations at the beginning of wheat's cultivation. Wheat with this mutation was harvested more frequently and became the seed for the next crop. Therefore, without realizing, early farmers selected for this mutation. The result is domesticated wheat, which relies on farmers for its reproduction and dissemination.


History

The earliest human attempts at plant domestication occurred in the
Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabia (including the Arabian Peninsula and Bahrain), Asia Minor (Asian part of Turkey except Hatay Province), East Thrace (Europea ...
. There is early evidence for conscious cultivation and trait selection of plants by pre-Neolithic groups in Syria: grains of
rye Rye (''Secale cereale'') is a grass grown extensively as a grain, a cover crop and a forage crop. It is a member of the wheat tribe (Triticeae) and is closely related to both wheat (''Triticum'') and barley (genus ''Hordeum''). Rye grain is u ...
with domestic traits dated 13,000 years ago have been recovered from Abu Hureyra in
Syria Syria ( ar, سُورِيَا or سُورِيَة, translit=Sūriyā), officially the Syrian Arab Republic ( ar, الجمهورية العربية السورية, al-Jumhūrīyah al-ʻArabīyah as-Sūrīyah), is a Western Asian country loc ...
, but this appears to be a localised phenomenon resulting from cultivation of stands of wild rye, rather than a definitive step towards domestication. The
bottle gourd Calabash (; ''Lagenaria siceraria''), also known as bottle gourd, white-flowered gourd, long melon, birdhouse gourd, New Guinea bean, Tasmania bean, and opo squash, is a vine grown for its fruit. It can be either harvested young to be consumed ...
(''Lagenaria siceraria'') plant, used as a container before the advent of ceramic technology, appears to have been domesticated 10,000 years ago. The domesticated bottle gourd reached the Americas from Asia by 8,000 years ago, most likely due to the migration of peoples from Asia to America. Cereal crops were first domesticated around 11,000 years ago in the
Fertile Crescent The Fertile Crescent ( ar, الهلال الخصيب) is a crescent-shaped region in the Middle East, spanning modern-day Iraq, Syria, Lebanon, Israel, Palestine and Jordan, together with the northern region of Kuwait, southeastern region of ...
in the Middle East. The first domesticated crops were generally annuals with large seeds or fruits. These included
pulses In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle (heartbeat) by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed near the surface of the body, such as at the ne ...
such as
pea The pea is most commonly the small spherical seed or the seed-pod of the flowering plant species ''Pisum sativum''. Each pod contains several peas, which can be green or yellow. Botanically, pea pods are fruit, since they contain seeds and d ...
s and grains such as
wheat Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeological ...
. The Middle East was especially suited to these species; the dry-summer climate was conducive to the evolution of large-seeded annual plants, and the variety of elevations led to a great variety of species. As domestication took place humans began to move from a
hunter-gatherer A traditional hunter-gatherer or forager is a human living an ancestrally derived lifestyle in which most or all food is obtained by foraging, that is, by gathering food from local sources, especially edible wild plants but also insects, fungi, ...
society to a settled
agricultural Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people ...
society. This change would eventually lead, some 4000 to 5000 years later, to the first
city state A city-state is an independent sovereign city which serves as the center of political, economic, and cultural life over its contiguous territory. They have existed in many parts of the world since the dawn of history, including cities such as ...
s and eventually the rise of
civilization A civilization (or civilisation) is any complex society characterized by the development of a state, social stratification, urbanization, and symbolic systems of communication beyond natural spoken language (namely, a writing system). Ci ...
itself. Continued domestication was gradual, a process of intermittent trial and error, and often resulted in diverging traits and characteristics. Over time perennials and small trees including the apple and the olive were domesticated. Some plants, such as the
macadamia nut ''Macadamia'' is a genus of four species of trees in the flowering plant family Proteaceae. They are indigenous to Australia, native to northeastern New South Wales and central and southeastern Queensland specifically. Two species of the genus ...
and the
pecan The pecan (''Carya illinoinensis'') is a species of hickory native to the southern United States and northern Mexico in the region of the Mississippi River. The tree is cultivated for its seed in the southern United States, primarily in Georgia, ...
, were not domesticated until recently. In other parts of the world very different species were domesticated. In the
Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with t ...
squash Squash may refer to: Sports * Squash (sport), the high-speed racquet sport also known as squash racquets * Squash (professional wrestling), an extremely one-sided match in professional wrestling * Squash tennis, a game similar to squash but pla ...
,
maize Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The ...
,
beans A bean is the seed of several plants in the family Fabaceae, which are used as vegetables for human or animal food. They can be cooked in many different ways, including boiling, frying, and baking, and are used in many traditional dishes thr ...
, and perhaps
manioc ''Manihot esculenta'', commonly called cassava (), manioc, or yuca (among numerous regional names), is a woody shrub of the spurge family, Euphorbiaceae, native to South America. Although a perennial plant, cassava is extensively cultivated a ...
(also known as
cassava ''Manihot esculenta'', commonly called cassava (), manioc, or yuca (among numerous regional names), is a woody shrub of the spurge family, Euphorbiaceae, native to South America. Although a perennial plant, cassava is extensively cultivated ...
) formed the core of the diet. In East Asia
millet Millets () are a highly varied group of small-seeded grasses, widely grown around the world as cereal crops or grains for fodder and human food. Most species generally referred to as millets belong to the tribe Paniceae, but some millets also ...
,
rice Rice is the seed of the grass species ''Oryza sativa'' (Asian rice) or less commonly ''Oryza glaberrima'' (African rice). The name wild rice is usually used for species of the genera '' Zizania'' and ''Porteresia'', both wild and domesticated, ...
, and
soy The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses. Traditional unfermented food uses of soybeans include soy milk, from which tofu and ...
were the most important crops. Some areas of the world such as
Southern Africa Southern Africa is the southernmost subregion of the African continent, south of the Congo and Tanzania. The physical location is the large part of Africa to the south of the extensive Congo River basin. Southern Africa is home to a number of ...
, Australia, California and southern South America never saw local species domesticated.


Differences from wild plants

Domesticated plants may differ from their wild relatives in many ways, including * the way they spread to a more diverse environment and have a wider geographic range; * different ecological preference (sun, water, temperature, nutrients, etc. requirements), different disease susceptibility; * conversion from a
perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...
to annual; * loss of
seed dormancy Seed dormancy is an evolutionary adaptation that prevents seeds from germinating during unsuitable ecological conditions that would typically lead to a low probability of seedling survival. Dormant seeds do not germinate in a specified period of ...
and
photoperiodic A circadian rhythm (), or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism (i.e., endogenous) and responds to ...
controls; * simultaneous flower and fruit, double flowers; * a lack of shattering or scattering of seeds, or even loss of their dispersal mechanisms completely; * less efficient breeding system (e.g. lack normal
pollinating Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds, a ...
organs, making human intervention a requirement), smaller seeds with lower success in the wild, or even complete sexual sterility (e.g. seedless fruits) and therefore only vegetative reproduction; * less defensive adaptations such as hairs,
thorns, spines, and prickles In plant morphology, thorns, spines, and prickles, and in general spinose structures (sometimes called ''spinose teeth'' or ''spinose apical processes''), are hard, rigid extensions or modifications of leaves, roots, stems or buds with sharp, st ...
, poison, protective coverings and sturdiness, rendering them more likely to be eaten by animals and pests unless cared by humans; * chemical composition, giving them better
palatability Palatability (or palatableness) is the hedonic reward (i.e., pleasure) provided by foods or fluids that are agreeable to the "palate", which often varies relative to the homeostatic satisfaction of nutritional, water, or energy needs. The palatabil ...
(e.g. sugar content), better smell, and lower toxicity; * edible part larger, and easier separated from non-edible part (e.g. freestone fruit).


The impact of domestication on the plant microbiome

The
microbiome A microbiome () is the community of microorganisms that can usually be found living together in any given habitat. It was defined more precisely in 1988 by Whipps ''et al.'' as "a characteristic microbial community occupying a reasonably well ...
, defined as the collection of
microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...
s inhabiting the surface and internal tissue of plants, has been shown to be affected by plant domestication and breeding. This includes variation the microbial community composition to change in the number of microbial species associated with plants, i.e., species diversity. Evidence also show that plant lineage, including
speciation Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within ...
, domestication, and
breeding Breeding is sexual reproduction that produces offspring, usually animals or plants. It can only occur between a male and a female animal or plant. Breeding may refer to: * Animal husbandry, through selected specimens such as dogs, horses, and rab ...
have shaped the plant
endophyte An endophyte is an endosymbiont, often a bacterium or fungus, that lives within a plant for at least part of its life cycle without causing apparent disease. Endophytes are ubiquitous and have been found in all species of plants studied to date; h ...
s in similar patterns as plant genes. Such patterns are also known as phylosymbiosis which have been observed in several animal and plant lineages.


Traits that are being genetically improved

There are many challenges facing modern farmers, including climate change, pests, soil salinity, drought, and periods with limited sunlight. Drought is one of the most serious challenges facing farmers today. With shifting climates comes shifting weather patterns, meaning that regions that could traditionally rely on a substantial amount of precipitation were, quite literally, left out to dry. In light of these conditions,
drought resistance Drought tolerance is the ability to which a plant maintains its biomass production during arid or drought conditions. Some plants are naturally adapted to dry conditions'','' surviving with protection mechanisms such as desiccation tolerance, detox ...
in major crop plants has become a clear priority. One method is to identify the genetic basis of drought resistance in naturally drought resistant plants, i.e. the
Bambara groundnut ''Vigna subterranea'' (common names: Bambara groundnut, Bambara nut, Bambara bean, Congo goober, earth pea, ground-bean, or hog-peanut) is a member of the family Fabaceae. Its name is derived from the Bambara tribe, who currently lives in Mali. T ...
. Next, transferring these advantages to otherwise vulnerable crop plants. Rice, which is one of the most vulnerable crops in terms of drought, has been successfully improved by the addition of the Barley hva1 gene into the genome using transgenetics. Drought resistance can also be improved through changes in a plant's root system architecture, such as a root orientation that maximizes water retention and nutrient uptake. There must be a continued focus on the efficient usage of available water on a planet that is expected to have a population in excess of nine-billion people by 2050. Another specific area of genetic improvement for domesticated crops is the crop plant's uptake and utilization of soil potassium, an essential element for crop plants yield and overall quality. A plant's ability to effectively uptake potassium and use it efficiently is known as its potassium utilization efficiency. It has been suggested that first optimizing plant root architecture and then root potassium uptake activity may effectively improve plant potassium utilization efficiency.


Crop plants that are being genetically improved

Cereal A cereal is any grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, germ, and bran. Cereal grain crops are grown in greater quantities and provide more food e ...
s, rice, wheat, corn,
sorghum ''Sorghum'' () is a genus of about 25 species of flowering plants in the grass family (Poaceae). Some of these species are grown as cereals for human consumption and some in pastures for animals. One species is grown for grain, while many other ...
and barley, make up a huge amount of the global diet across all demographic and social scales. These cereal crop plants are all autogamous, i.e. self-fertilizing, which limits overall diversity in allelic combinations, and therefore adaptability to novel environments. To combat this issue the researchers suggest an "Island Model of Genomic Selection". By breaking a single large population of cereal crop plants into several smaller sub-populations which can receive "migrants" from the other subpopulations, new genetic combinations can be generated. The Bambara groundnut is a durable crop plant that, like many underused crops, has received little attention in an agricultural sense. The Bambara Groundnut is drought resistant and is known to be able to grow in almost any soil conditions, no matter how impoverished an area may be. New genomic and transcriptomic approaches are allowing researchers to improve this relatively small-scale crop, as well as other large-scale crop plants. The reduction in cost, and wide availability of both
microarray A microarray is a multiplex lab-on-a-chip. Its purpose is to simultaneously detect the expression of thousands of genes from a sample (e.g. from a tissue). It is a two-dimensional array on a solid substrate—usually a glass slide or silico ...
technology and Next Generation Sequencing have made it possible to analyze underused crops, like the groundnut, at genome-wide level. Not overlooking particular crops that don't appear to hold any value outside of the developing world will be key to not only overall crop improvement, but also to reducing the global dependency on only a few crop plants, which holds many intrinsic dangers to the global population's food supply.


Challenges facing genetic improvement

The semi-arid tropics, ranging from parts of North and South Africa, Asia especially in the South Pacific, all the way to Australia are notorious for being both economically destitute and agriculturally difficult to cultivate and farm effectively. Barriers include everything from lack of rainfall and diseases, to economic isolation and environmental irresponsibility. There is a large interest in the continued efforts, of the
International Crops Research Institute for the Semi-Arid Tropics The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) is an international organization which conducts agricultural research for rural development, headquartered in Patancheru (Hyderabad, Telangana, India) with several re ...
(ICRSAT) to improve staple foods. some mandated crops of ICRISAT include the groundnut, pigeonpea, chickpea, sorghum and pearl millet, which are the main staple foods for nearly one billion people in the semi-arid tropics. As part of the ICRISAT efforts, some wild plant breeds are being used to transfer genes to cultivated crops by interspecific hybridization involving modern methods of embryo rescue and tissue culture. One example of early success has been work to combat the very detrimental peanut clump virus. Transgenetic plants containing the coat protein gene for resistance against peanut clump virus have already been produced successfully. Another region threatened by food security are the Pacific Island Countries, which are disproportionally faced with the negative effects of climate change. The Pacific Islands are largely made up of a chain of small bodies of land, which obviously limits the amount of geographical area in which to farm. This leaves the region with only two viable options 1.) increase agricultural production or 2.) increase food importation. The latter of course runs into the issues of availability and economic feasibility, leaving only the first option as a viable means to solve the region's food crisis. It is much easier to misuse the limited resources remaining, as compared with solving the problem at its core.


Working with wild plants to improve domestics

Work has also has been focusing on improving domestic crops through the use of
crop wild relative A crop wild relative (CWR) is a wild plant closely related to a domesticated plant. It may be a wild ancestor of the domesticated (cultivated) plant or another closely related taxon. Overview The wild relatives of crop plants constitute an ...
s. The amount and depth of genetic material available in crop wild relatives is larger than originally believed, and the range of plants involved, both wild and domestic, is ever expanding. Through the use of new biotechnological tools such as genome editing,
cisgenesis Cisgenesis is a product designation for a category of genetically engineered plants. A variety of classification schemes have been proposed that order genetically modified organisms based on the nature of introduced genotypical changes, rather th ...
/intragenesis, the transfer of genes between crossable donor species including hybrids, and other omic approaches. Wild plants can be hybridized with crop plants to form perennial crops from annuals, increase yield, growth rate, and resistance to outside pressures like disease and drought. Importantly, these changes take significant lengths of time to achieve, sometimes even decades. However, the outcome can be extremely successful as is the case with a hybrid grass variant known as '' Kernza.'' Over the course of nearly three decades, work was done on an attempted hybridization between an already domesticated grass strain, and several of its wild relatives. The domesticated strain as was more uniform in its orientation, but the wild strains were larger and propagated faster. The resulting ''Kernza'' crop has traits from both progenitors: uniform orientation and a linearly vertical root system from the domesticated crop, along with increased size and rate of propagation from the wild relatives.


Fungi and micro-organisms

Several species of
fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from t ...
have been domesticated for use directly as food, or in fermentation to produce foods and drugs. The white button mushroom ''
Agaricus bisporus ''Agaricus bisporus'' is an edible basidiomycete mushroom native to grasslands in Eurasia and North America. It has two color states while immature – white and brown – both of which have various names, with additional names for the mature ...
'' is widely grown for food. The yeast ''
Saccharomyces cerevisiae ''Saccharomyces cerevisiae'' () (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungus microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have been ...
'' have been used for thousands of years to ferment beer and wine, and to leaven bread. Mould fungi including ''
Penicillium ''Penicillium'' () is a genus of ascomycetous fungi that is part of the mycobiome of many species and is of major importance in the natural environment, in food spoilage, and in food and drug production. Some members of the genus produce pe ...
'' are used to mature cheeses and other dairy products, as well as to make drugs such as
antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...
.


Effects


On domestic animals

Selection of animals for visible "desirable" traits may have undesired consequences. Captive and domesticated animals often have smaller size,
piebald A piebald or pied animal is one that has a pattern of unpigmented spots (white) on a pigmented background of hair, feathers or scales. Thus a piebald black and white dog is a black dog with white spots. The animal's skin under the white backgro ...
color, shorter faces with smaller and fewer teeth, diminished horns, weak muscle ridges, and less genetic variability. Poor joint definition, late fusion of the limb bone
epiphyses The epiphysis () is the rounded end of a long bone, at its joint with adjacent bone(s). Between the epiphysis and diaphysis (the long midsection of the long bone) lies the metaphysis, including the epiphyseal plate (growth plate). At the join ...
with the diaphyses, hair changes, greater fat accumulation, smaller brains, simplified behavior patterns, extended immaturity, and more pathology are among the defects of domestic animals. All of these changes have been documented by archaeological evidence, and confirmed by animal breeders in the 20th century. In 2014, a study proposed the theory that under selection, docility in mammals and birds results partly from a slowed pace of
neural crest Neural crest cells are a temporary group of cells unique to vertebrates that arise from the embryonic ectoderm germ layer, and in turn give rise to a diverse cell lineage—including melanocytes, craniofacial cartilage and bone, smooth muscle, pe ...
development, that would in turn cause a reduced fear–startle response due to mild
neurocristopathy Neurocristopathy is a diverse class of pathologies that may arise from defects in the development of tissues containing cells commonly derived from the embryonic neural crest cell lineage. The term was coined by Robert P. Bolande in 1974. After th ...
that causes domestication syndrome. The theory was unable to explain curly tails nor domestication syndrome exhibited by plants. A side effect of domestication has been
zoonotic A zoonosis (; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a bacterium, virus, parasite or prion) that has jumped from a non-human (usually a vertebrate) to a huma ...
diseases. For example, cattle have given humanity various viral poxes,
measles Measles is a highly contagious infectious disease caused by measles virus. Symptoms usually develop 10–12 days after exposure to an infected person and last 7–10 days. Initial symptoms typically include fever, often greater than , cough, ...
, and
tuberculosis Tuberculosis (TB) is an infectious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in w ...
; pigs and ducks have given
influenza Influenza, commonly known as "the flu", is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptoms ...
; and horses have given the
rhinovirus The rhinovirus (from the grc, ῥίς, rhis "nose", , romanized: "of the nose", and the la, vīrus) is the most common viral infectious agent in humans and is the predominant cause of the common cold. Rhinovirus infection proliferates in tem ...
es. Many parasites have their origins in domestic animals. The advent of domestication resulted in denser human populations which provided ripe conditions for pathogens to reproduce, mutate, spread, and eventually find a new host in humans.
Paul Shepard Paul Howe Shepard, Jr. (June 12, 1925 – July 27, 1996) was an American environmentalist and author best known for introducing the "Pleistocene paradigm" to deep ecology. His works established a normative framework in terms of evolutionary ...
writes "Man substitutes controlled breeding for natural selection; animals are selected for special traits like milk production or passivity, at the expense of overall fitness and nature-wide relationships...Though domestication broadens the diversity of forms – that is, increases visible polymorphism – it undermines the crisp demarcations that separate wild species and cripples our recognition of the species as a group. Knowing only domestic animals dulls our understanding of the way in which unity and discontinuity occur as patterns in nature, and substitutes an attention to individuals and breeds. The wide variety of size, color, shape, and form of domestic horses, for example, blurs the distinction among different species of ''Equus'' that once were constant and meaningful."


On society

Jared Diamond Jared Mason Diamond (born September 10, 1937) is an American geographer, historian, ornithologist, and author best known for his popular science books ''The Third Chimpanzee'' (1991); ''Guns, Germs, and Steel'' (1997, awarded a Pulitzer Prize); ...
in his book ''
Guns, Germs, and Steel ''Guns, Germs, and Steel: The Fates of Human Societies'' (subtitled ''A Short History of Everybody for the Last 13,000 Years'' in Britain) is a 1997 transdisciplinary non-fiction book by Jared Diamond. In 1998, it won the Pulitzer Prize for gen ...
'' describes the universal tendency for populations that have acquired agriculture and domestic animals to develop a large population and to expand into new territories. He recounts migrations of people armed with domestic crops overtaking, displacing or killing indigenous hunter-gatherers, whose lifestyle is coming to an end. Some anarcho-primitivist authors describe domestication as the process by which previously
nomadic A nomad is a member of a community without fixed habitation who regularly moves to and from the same areas. Such groups include hunter-gatherers, pastoral nomads (owning livestock), tinkers and trader nomads. In the twentieth century, the pop ...
human populations shifted towards a sedentary or settled existence through
agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...
and
animal husbandry Animal husbandry is the branch of agriculture concerned with animals that are raised for meat, fibre, milk, or other products. It includes day-to-day care, selective breeding, and the raising of livestock. Husbandry has a long history, startin ...
. They claim that this kind of domestication demands a totalitarian relationship with both the land and the plants and animals being domesticated. They say that whereas, in a state of wildness, all life shares and competes for resources, domestication destroys this balance. Domesticated landscape (e.g. pastoral lands/agricultural fields and, to a lesser degree,
horticulture Horticulture is the branch of agriculture that deals with the art, science, technology, and business of plant cultivation. It includes the cultivation of fruits, vegetables, nuts, seeds, herbs, sprouts, mushrooms, algae, flowers, seaweeds and no ...
and
gardening Gardening is the practice of growing and cultivating plants as part of horticulture. In gardens, ornamental plants are often grown for their flowers, foliage, or overall appearance; useful plants, such as root vegetables, leaf vegetables, fruits ...
) ends the open sharing of resources; where "this was everyone's", it is now "mine". Anarcho-primitivists state that this notion of ownership laid the foundation for social
hierarchy A hierarchy (from Greek: , from , 'president of sacred rites') is an arrangement of items (objects, names, values, categories, etc.) that are represented as being "above", "below", or "at the same level as" one another. Hierarchy is an important ...
as property and power emerged. It also involved the destruction, enslavement, or assimilation of other groups of early people who did not make such a transition. Under the framework of
Dialectical naturalism Murray Bookchin (January 14, 1921 – July 30, 2006) was an American social theorist, author, orator, historian, and political philosopher. A pioneer in the environmental movement, Bookchin formulated and developed the theory of social ...
,
Murray Bookchin Murray Bookchin (January 14, 1921 – July 30, 2006) was an American social theorist, author, orator, historian, and political philosopher. A pioneer in the environmental movement, Bookchin formulated and developed the theory of social e ...
has argued that the basic notion of domestication is incomplete: That, since the domestication of animals is a crucial development within human history, it can also be understood as the domestication of humanity itself in turn. Under this dialectical framework, domestication is always a 'two-way street' with both parties being unavoidably altered by their relationship with each other.
David Nibert David Alan Nibert (born 1953) is an American sociologist, author, activist and professor of sociology at Wittenberg University. He is the co-organizer of the Section on Animals and Society of the American Sociological Association. In 2005, he r ...
, professor of sociology at
Wittenberg University Wittenberg University is a private liberal arts college in Springfield, Ohio. It has 1,326 full-time students representing 33 states and 9 foreign countries. Wittenberg University is associated with the Evangelical Lutheran Church in America. ...
, posits that the domestication of animals, which he refers to as "domesecration" as it often involved extreme violence against animal populations and the devastation of the environment, resulted in the corruption of human ethics, and helped pave the way for societies steeped in "conquest, extermination, displacement, repression, coerced and enslaved servitude, gender subordination and sexual exploitation, and hunger."


On diversity

In 2016, a study found that humans have had a major impact on global
genetic diversity Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is dis ...
as well as extinction rates, including a contribution to megafaunal extinctions. Pristine landscapes no longer exist and have not existed for millennia, and humans have concentrated the planet's biomass into human-favored plants and animals. Domesticated ecosystems provide food, reduce predator and natural dangers, and promote commerce, but have also resulted in habitat loss and extinctions commencing in the Late Pleistocene. Ecologists and other researchers are advised to make better use of the archaeological and paleoecological data available for gaining an understanding the history of human impacts before proposing solutions.


See also

*
Animal–industrial complex The term animal–industrial complex (AIC) refers to the systematic and institutionalized exploitation of animals. It includes every economic activity involving animals, such as the food industry (e.g., meat, dairy, poultry, apiculture), animal ...
*
Anthrozoology Anthrozoology, also known as human–nonhuman-animal studies (HAS), is the subset of ethnobiology that deals with biological interaction, interactions between humans and other animals. It is an interdisciplinary field that overlaps with other ...
*
Columbian Exchange The Columbian exchange, also known as the Columbian interchange, was the widespread transfer of plants, animals, precious metals, commodities, culture, human populations, technology, diseases, and ideas between the New World (the Americas) in ...
*
Domestication theory Domestication theory is an approach in Science and Technology Studies (STS) and media studies that describe the processes by which technology is 'tamed' or appropriated by its users. The theory was originally created by Roger Silverstone, who des ...
*
Experimental evolution Experimental evolution is the use of laboratory experiments or controlled field manipulations to explore evolutionary dynamics. Evolution may be observed in the laboratory as individuals/populations adapt to new environmental conditions by natura ...
*
Genetic engineering Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including t ...
*
Genetic erosion Genetic erosion (also known as genetic depletion) is a process where the limited gene pool of an endangered species diminishes even more when reproductive individuals die off before reproducing with others in their endangered low population. The t ...
* Genomics of domestication * History of plant breeding * Marker assisted selection *
Pet A pet, or companion animal, is an animal kept primarily for a person's company or entertainment rather than as a working animal, livestock, or a laboratory animal. Popular pets are often considered to have attractive appearances, intelligence, ...
*
Self-domestication Self-domestication is the process of adaptation of for example wild animals to cohabiting with humans, without direct human selective breeding of the animals. The human self-domestication hypothesis argues that, like mammalian domesticates, humans ...
* Timeline of agriculture and food technology * Wild ancestors


Notes


References


Further reading

* * Brian Hare and Vanessa Woods, "Survival of the Friendliest: Natural selection for hypersocial traits enabled Earth's apex species to best Neandertals and other competitors", ''
Scientific American ''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many famous scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it. In print since 1845, it i ...
'', vol. 323, no. 2 (August 2020), pp. 58–63. * *


External links


Crop Wild Relative Inventory and Gap Analysis
reliable information source on where and what to conserve ex-situ, for crop genepools of global importance


The Initial Domestication of ''Cucurbita pepo'' in the Americas 10,000 Years Ago

Cattle domestication diagram

Major topic 'domestication': free full-text articles (more than 100 plus reviews) in National Library of Medicine
{{Authority control History of agriculture