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45. What is genetic drift?

Genetic drift occurs in small isolated populations causing certain genotypes to become dominant even if there is no selection benefits in that phenotype.

Gradually in small isolated populations, through random mating, slowly begins to change the gene composition. In this case the brown colored genes slowly become more frequent then the green colored genes. The green color will eventually become lost. In large populations, with larger numbers of beetles contributing to the gene pool, the genotype more easily stabilizes and stays the same.

Here are some examples of genetic drift: