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LECTURE 16: MEASURING GENETIC DIVERSITY
Fisher & Haldane: quantitative aspects of evolutionary change; population genetics into evolution
Wright: mendelian law, natural selection, and continuous variation – mathematical
Synthesis of ecology (Darwinian natural selection and genetics)
Theory of impericism.
Not all genes are variable
What forces influence diversity?
•Random genetic drift ( small population size effects)
oCan lead to reduction in diversity
oPurifying ( negative) – reduce fitness removed by selection
oPositive selection (adaptation) – mutatuion arises and is favoured.
oBalancing selection – heterozygotes are favoured over homozygotes
Fisher felt that all important evolution occurred in large population by natural selection; genetic drift=
Wright – genetic drift played important role in evolution
^CONTROVERSY IN EVOLUTIONARY BELIEFS
Importance of mechanism:
•Mutation and strength of selection
•Natural selection taking mutatuions out
•Differet selective forces