The gene pool is the set of all
gene
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 b ...
s, or
genetic information
A nucleic acid sequence is a succession of bases signified by a series of a set of five different letters that indicate the order of nucleotides forming alleles within a DNA (using GACT) or RNA (GACU) molecule. By convention, sequences are u ...
, in any
population
Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction usi ...
, usually of a particular
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 appropriat ...
.
Description
A large gene pool indicates extensive
genetic diversity, which is associated with robust populations that can survive bouts of intense
selection. Meanwhile, low
genetic diversity (see
inbreeding
Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genetic disorders a ...
and
population bottlenecks) can cause reduced
biological fitness and an increased chance of
extinction
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the Endling, last individual of the species, although the Functional ext ...
, although as explained by
genetic drift
Genetic drift, also known as allelic drift or the Wright effect, is the change in the frequency of an existing gene variant (allele) in a population due to random chance.
Genetic drift may cause gene variants to disappear completely and there ...
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
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 pr ...
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
Theodosius Grigorievich Dobzhansky (russian: Феодо́сий Григо́рьевич Добржа́нский; uk, Теодо́сій Григо́рович Добржа́нський; January 25, 1900 – December 18, 1975) was a prominent ...
, 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
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 appropriat ...
" (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
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins ar ...
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 (biology), morphology or physical form and structure, its Developmental biology, developmental proc ...
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 (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 b ...
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)
#*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 or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic ('' genetic variability''), species ('' species diversity''), and ecosystem ('' ecosystem diversity'') ...
*
Conservation biology
*
Founder effect
*
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 ...
*
Genetic drift
Genetic drift, also known as allelic drift or the Wright effect, is the change in the frequency of an existing gene variant (allele) in a population due to random chance.
Genetic drift may cause gene variants to disappear completely and there ...
*
Small population size
*
Australian Grains Genebank
References
{{DEFAULTSORT:Gene Pool
Ecology
Conservation biology
Selection
Genetics concepts
Classical genetics
Population genetics
Evolutionary biology
Biorepositories