Biology 1001A Lecture Notes - Lecture 14: Heterozygote Advantage, Lethal Allele, Genetic Drift

• School: Western University
• Department: Biology
• Course: Biology 1001A
• Professor: Scott Mac Dougall- Shackleton

Document Summary

Variation in population evolutionary agents & maintaining. Processes that produce genetic variation and foster micro evolutionary change: mutation, gene flow, genetic drift, natural selection and non-random mating. Studies of chromosomal and mitochondrial dna suggest that every locus exhibits some variability in its nucleotide sequence among individuals from a single population, between populations of the same species, and between related species. Mutation: spontaneous and heritable change in dna. New mutations are infrequent: they exert little or no immediate effect on allele frequencies in most populations, over evolutionary time, their numbers are significant; mutations have been accumulating in biological lineages for billions of years. And because it creates entirely new genetic variations, a mutation can be a major source of heritable variation. For most animals, only mutations in the germ line (the cell lineage that produces gametes) are heritable; mutations in other cell lineages have no direct effect on the next generation.