Gene flow, genetic drift and non-random mating - 17.3

Gene flow, genetic drift and non-random mating - 17.3 -...

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Differences arise in both exited and entered pop'ns Alleles lost in one pop'n, and gained in another "Allele flow" --- transfer of alleles in and out of population Makes two pop'ns genetically alike - Can equalize two pop'ns - Continual exchange --> reduces genetic difference s btw popns - Gene Flow: Indvs of Spp A travel to new pop'n of Spp A Caused by migration of indivs btw popns of same spp - Immigration/emigration - (in order to affect allele freqs of recipient pop'n) When indvs leave one popn and join another and BREED in it - Young male baboons: move to another pop'n after bullying by older males Marine invertebrates: shed their gametes into the water , carried by current, mixes in new pop'ns Pollen : carried by wind, incorporated into gene pools of new pop'ns in new locations (same spp!) Integration of alleles from another popn - Therefore does not result in adaptation So the gain and loss of new alleles is due to movement of indv into pop'ns but it can end up increasing/decreasing fitness of recipient pop'n - Random with respects to fitness (unlike Nat Sel'n) after the migration, both pop'ns have a change in allele freqs Differences arise in both exited and entered pop'ns Alleles lost in one pop'n and gained in another Different in beginning -- more Similar after indvs migrate into ALREADY ESTABLISHED POP'N. Founder's establishes new pop'n. Different to Founders Effect (genetic drift): change is unpredictable - Change in alle freqs of a pop'n due to chance Unlike Nat Sel'n, COMPLETELY RANDOM to fitness of indvs - Genetic Drift: change in allele freqs = DUE TO CHANCE - not selective advantages - not related to fitness - COMPLETELTY RANDOM Alleles of the next gen are the alleles that happen to be lucky and get there - Indvs who survive are just lucky Genetic Drift Increased effect in small pop'ns - Can cause harmful alleles to
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This note was uploaded on 03/15/2011 for the course BIOL 1010 taught by Professor Anafi/quinlan during the Spring '08 term at York University.

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Gene flow, genetic drift and non-random mating - 17.3 -...

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