ESPM 108B Lecture Notes - Lecture 10: Sub Pop, Genetic Drift, Panmixia

• School: Berkeley
• Department: Environmental Science, Policy, And Management
• Course: ESPM 108B
• Professor: Richard Dodd

Document Summary

Genetic drift and selection are 2 most powerful forces that change allele. If pops are nite, stochastic sampling will lead to loss/ xation of alleles. In closed pop, inexorable loss of diversity is balanced by mutations. Bc env changes commonly lead to fragmentation, isolation, colonization, or divergence/speciation, we"re interested in what happens to small pops. Want to know what genetic diversity could be expected if pops decline to certain size. Want to infer if pops have gone thru bottleneck and for how long. Want to know how many indiv are contributing to genetic diversity and how it differs from census size. Non-directional, so the gradual loss of alleles that occurs thru drift is stochastic and is proportional to the freq of the alleles in the pop. Wright-fisher model: use properties of binomial dist to model chgs in allele freq. View held today is that both can be potent forces of evolutionary change.