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Assisted evolution (sometimes referred to as human-assisted evolution) is the practice of using human intervention to accelerate the rate of natural
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 processes. The goal of assisted evolution is to help
species In biology, a species is the basic unit of 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 the appropriate s ...
adapt to a changing environment more quickly than they would via
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. Charle ...
. Assisted evolution can be used to increase food production and crop yield, as well as ensure targeted species to more quickly become resistant to existential threats. Assisted evolution has been practiced for thousands of years, often for commercial and business purposes. Assisted evolution has come into the public eye in recent years for noncommercial purposes such as species
conservation Conservation is the preservation or efficient use of resources, or the conservation of various quantities under physical laws. Conservation may also refer to: Environment and natural resources * Nature conservation, the protection and managem ...
. Assisted evolution for noncommercial purposes is most notably practiced in the attempt to save coral reefs from rising global ocean temperatures and other
climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
related environmental conditions.


History


Commercial purposes

Assisted evolution has been practiced for thousands of years for commercial and business purposes.
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 mal ...
of Asian wolves over 30,000 years ago by
hunter-gatherers 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, ...
have allowed for the creation of modern breeds such as the
German Shepherd The German Shepherd or Alsatian is a German breed of working dog of medium to large size. The breed was developed by Max von Stephanitz using various traditional German herding dogs from 1899. It was originally bred as a herding dog, for he ...
, which are used often for disability assistance, search-and-rescue, and police and military roles. Plant breeding has also benefitted from Rapid Generation Advance (RGA) and single-seed descent to speed up the process of natural selection. Assisted evolution in plants have allowed for increased food production and reduced
pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...
use, yielding a decrease in global poverty and
malnutrition Malnutrition occurs when an organism gets too few or too many nutrients, resulting in health problems. Specifically, it is "a deficiency, excess, or imbalance of energy, protein and other nutrients" which adversely affects the body's tissues a ...
. Most recently, assisted evolution is being used to breed animals with a higher muscle or fat content, as well as have a higher resistance to harmful bacteria and other
pathogens In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...
.


Non-commercial purposes

Assisted evolution for non-commercial purposes was famously used by
Gregor Mendel Gregor Johann Mendel, Augustinians, OSA (; cs, Řehoř Jan Mendel; 20 July 1822 – 6 January 1884) was a biologist, meteorologist, mathematician, Augustinians, Augustinian friar and abbot of St Thomas's Abbey, Brno, St. Thomas' Abbey in Brà ...
, who discovered the presence of
genes In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
and
alleles An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chro ...
, as well as their impact on an offspring's
genotype The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location. The number of alleles an individual can have in a ...
. Assisted evolution has come into the public eye for noncommercial purposes such as conservation in recent years. Assisted evolution for noncommercial purposes is most notably practiced in the attempt to save
coral reefs A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of Colony (biology), colonies of coral polyp (zoology), polyps held together by calcium carbonate. Most coral reefs are built from stony corals, wh ...
from rising ocean temperatures. Assisted evolution is believed to be a temporary solution to save many threatened species from
global warming In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
and other climate change related environmental changes.


Types


Stress conditioning

Stress conditioning consists of exposing organisms to sublethal stress, with the goal of inducing physiological changes that increase tolerance to future stress events. There has been documented evidence that some changes can be passed throughout generations in both plants and animals. Stress conditioning can be artificially induced in a laboratory environment to create desired responses based on their environments. Notable examples include a 1989 experiment which used stress conditioning via heat shock on rat kidneys to extend their safe cold storage time to 48 hours. More recently, stress conditioning is being studied as a potential solution for the preservation of coral reefs as they are continually exposed to ocean warming and acidification.


Assisted gene flow (AGF)

Assisted gene flow (AGF) works to increase the presence of desired naturally-occurring genes in
offspring In biology, offspring are the young creation of living organisms, produced either by a single organism or, in the case of sexual reproduction, two organisms. Collective offspring may be known as a brood or progeny in a more general way. This ca ...
. AGF relies on pre-existing genes within the species’
genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...
, rather than the artificial creation and insertion of genetic code within the genome of the species. Assisted gene flow can also introduce related species’ genomes into the
gene pool The gene pool is the set of all genes, or genetic information, in any population, usually of a particular species. Description A large gene pool indicates extensive genetic diversity, which is associated with robust populations that can surv ...
to allow for the introduction of previously impossible behaviors into the new species. Assisted gene flow identifies genes that produce desired behaviors, and works to increase the chance that parental transmission of the gene in question occurs (also known as
heritability Heritability is a statistic used in the fields of breeding and genetics that estimates the degree of ''variation'' in a phenotypic trait in a population that is due to genetic variation between individuals in that population. The concept of h ...
). Determining which genes within the genome produce desired behaviors consist of experiments which measure the growth, survival, and behavior exhibition of offspring with varying genotypes. Assisted gene flow is being utilized as a solution to preserve species who are threatened by climate change. Currently, different colonies of the
Great Barrier Reef The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over over an area of approximately . The reef is located in the Coral Sea, off the coast of Queensland, ...
are being interbred to test whether offspring display increased resistance to warmer living conditions. Increased resistance to warmer living conditions allow for the
preservation Preservation may refer to: Heritage and conservation * Preservation (library and archival science), activities aimed at prolonging the life of a record while making as few changes as possible * ''Preservation'' (magazine), published by the Nat ...
of the Great Barrier Reef even as water temperatures continue to rise.


Hybridization

Hybridization refers to the process where an egg and sperm from two different species can fertilize and produce young. Hybridization was studied in the 1800s by Johann Gregor Mendel, who posthumously has been credited with the discovery of genes and alleles and their impact on an offspring's genotype. Benefits of hybridization include the increase in genetic diversity and the potential for genetic combinations which are able to adapt to, and reproduce in, increasingly difficult environments. Hybridization of coral reefs during the annual coral spawning is being experimented with to create hybrid offspring that will hopefully have higher survival and growth rates in a variety of climate change related conditions.


See also

* Assisted colonization *
Genetically modified organism A genetically modified organism (GMO) is any organism whose genetic material has been altered using genetic engineering techniques. The exact definition of a genetically modified organism and what constitutes genetic engineering varies, with ...
*
Genetic engineering techniques Genetic engineering techniques allow the modification of animal and plant genomes. Techniques have been devised to insert, delete, and modify DNA at multiple levels, ranging from a specific base pair in a specific gene to entire genes. There are ...


References

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External links


Reef Rescue
- Scientists race to help corals adapt to warming oceans through assisted evolution. NOVA Series TV Show from PBS. April 21, 2021. Evolution Nova (American TV program) episodes