Genetic Variation

∞ generated and posted on 2016.12.22 ∞

Presence of more than one allele per one or more loci within a population.

Genetic Variation is a description of the number or indeed existence of different alleles (gene variants) that are found at specific locations (loci) in genomes (chromosomes) as found within populations of organisms. The greater genetic variation then potentially the greater the phenotypic diversity within a population and the greater a population's potential to evolve.

Genetic variation is the "" of evolution since allele frequencies cannot change unless individual allele frequencies are not equal to 1. Similarly, natural selection cannot distinguish between alleles found at specific loci unless those alleles differ, which is another way of saying, unless genetic variation exists at that locus.

Genetic variation also can be described as consisting of one or more polymorphisms. An absence of genetic variation at a given locus would, by contrast, represent a . Even given polymorphism, there can be variations in the degree of genetic variation present, with more alleles as well as less dominance by any one allele at a given locus both representing greater levels of genetic variation (with a monomorphism representing the extreme of a lack of genetic variation).

Figure legend: Inadvertent experiment demonstrating genetic variation within a population, courtesy of my daughter: Two varieties of radish, one long, large, and white (Diakon) and the other round, small, and red (German Giant) were planted in adjacent beds and allowed to go to seed. This is the result, approximately one-year later.

Figure legend: Same species, different color flowers, growing side by side on the side the road.

Interestingly, genetic variation does not necessarily translate into selectable variation, a concept described as neutral variation as associated with neutral alleles.

The following video provides a brief as well as basic discussion of the diversity of origins of genetic variation in individuals:

Radio (Consideration of a small population of members of genus Homo as found in , )


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