The gene pool is the set of all
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
s, or
genetic information
A nucleic acid sequence is a succession of Nucleobase, bases within the nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. This succession is denoted by a series of a set of five different letters that indicate the orde ...
, in any
population
Population is a set of humans or other organisms in a given region or area. Governments conduct a census to quantify the resident population size within a given jurisdiction. The term is also applied to non-human animals, microorganisms, and pl ...
, usually of a particular
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
.
Description
A large gene pool indicates extensive
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 correlated to the span of survival for a species. It is d ...
, which is associated with robust populations that can survive bouts of intense
selection. Meanwhile, low
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 correlated to the span of survival for a species. It is d ...
(see
inbreeding
Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely genetic distance, related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genet ...
and
population bottlenecks) can cause reduced
biological fitness and an increased chance of
extinction
Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
, although as explained by
genetic drift
Genetic drift, also known as random genetic drift, allelic drift or the Wright effect, is the change in the Allele frequency, frequency of an existing gene variant (allele) in a population due to random chance.
Genetic drift may cause gene va ...
new genetic variants, that may cause an increase in the
fitness of organisms, are more likely to fix in the population if it is rather small.
When all individuals in a population are identical with regard to a particular
phenotypic trait, the population is said to be 'monomorphic'. When the individuals show several variants of a particular trait they are said to be
polymorphic.
History
The Russian geneticist
Alexander Sergeevich Serebrovsky first formulated the concept in the 1920s as ''genofond'' (gene fund), a word that was imported to the United States from the Soviet Union by
Theodosius Dobzhansky, who translated it into English as "gene pool."
Gene pool concept in crop breeding
Harlan and de Wet (1971) proposed classifying each crop and its related species by gene pools rather than by formal taxonomy.
#Primary gene pool (GP-1): Members of this gene pool are probably in the same "
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
" (in conventional biological usage) and can intermate freely. Harlan and de Wet wrote, "Among forms of this gene pool, crossing is easy;
hybrids are generally fertile with good chromosome pairing; gene segregation is approximately normal and
gene transfer is generally easy.".
They also advised subdividing each crop gene pool in two:
#*Subspecies A: Cultivated races
#*Subspecies B: Spontaneous races (wild or weedy)
#Secondary gene pool (GP-2): Members of this pool are probably normally classified as different species than the crop species under consideration (the primary gene pool). However, these species are closely related and can cross and produce at least some fertile hybrids. As would be expected by members of different species, there are some reproductive barriers between members of the primary and secondary gene pools:
#*hybrids may be weak
#*hybrids may be partially sterile
#*
chromosomes may pair poorly or not at all
#*recovery of desired
phenotype
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological propert ...
s may be difficult in subsequent generations
#*However, "The gene pool is available to be utilized, however, if the plant breeder or geneticist is willing to put out the effort required."
#Tertiary gene pool (GP-3): Members of this gene pool are more distantly related to the members of the primary gene pool. The primary and tertiary gene pools can be intermated, but
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
transfer between them is impossible without the use of "rather extreme or radical measures"
such as:
#*embryo rescue (or embryo culture, a form of plant
organ culture
Organ and organs may refer to:
Biology
* Organ (biology), a group of tissues organized to serve a common function
* Organ system, a collection of organs that function together to carry out specific functions within the body.
Musical instruments
...
)
#*induced
polyploidy (chromosome doubling)
#*bridging crosses (e.g., with members of the secondary gene pool).
Gene pool centres
Gene pool centres refers to areas on the earth where important crop plants and domestic animals originated. They have an extraordinary range of the wild counterparts of cultivated plant species and useful tropical plants.
Gene pool centres also contain different sub tropical and temperate region species.
See also
*
Biodiversity
Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...
*
Conservation biology
Conservation biology is the study of the conservation of nature and of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions. It is an i ...
*
Founder effect
In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. It was first fully outlined by Ernst Mayr in 1942, us ...
*
Gene flow
In population genetics, gene flow (also known as migration and allele flow) is the transfer of genetic variation, genetic material from one population to another. If the rate of gene flow is high enough, then two populations will have equivalent ...
*
Genetic drift
Genetic drift, also known as random genetic drift, allelic drift or the Wright effect, is the change in the Allele frequency, frequency of an existing gene variant (allele) in a population due to random chance.
Genetic drift may cause gene va ...
*
Small population size
*
Australian Grains Genebank
References
{{DEFAULTSORT:Gene Pool
Ecology
Conservation biology
Selection
Genetics concepts
Classical genetics
Population genetics
Evolutionary biology
Biorepositories