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Additional Sources of Variatio1

Additional Sources of Variatio1 - chance inbreeding can...

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Additional Sources of Variation Gene flow moves alleles among populations through interbreeding as well as by migration of breeding individuals. Gene flow increases variation within a population by introducing new alleles produced in another population. Continued gene flow tends to decrease the diversity among populations, causing gene pools to become similar. Reduction or restriction of gene flow between populations is essential for the development of new species. The frequency of alleles can change from generation to generation as a result of chance alone in a small gene pool. This phenomenon is known as genetic drift . Random mating involves individuals pairing by chance, not according to their genotypes or phenotypes. Nonrandom mating involves individuals inbreeding and assortative mating. Inbreeding is mating between relatives to a greater extent than by
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Unformatted text preview: chance; inbreeding can occur if dispersal is so low that mates are likely to be related and does not change allele frequencies, but it does decrease the proportion of heterozygotes and increase the proportions of both homozygotes at all gene loci. Assortative mating occurs when individuals tend to mate with those that have the same phenotype. Assortative mating divides a population into two phenotypic classes with reduced gene exchange. Genetic drift is changes in allele frequencies of a gene pool due to chance or random events. This can occur in large or small populations. Genetic drift causes gene pools of two isolated populations to become dissimilar as some alleles are lost and other are fixed....
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