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Lecture 10-11: Population Genetics and Mechanisms of Evolution

Terms in this set (53)

Kerr and Wright started with large lab population of fruit flies that contained a GENETIC MARKER - a specific allele that causes a distinctive phenotype. in this case, the marker was the morphology of bristles. fruit flies have bristles on their bodies that can either be straight or bent. this differences in bristle phenotype depends on a single gene. Kerr and Wright's lab pop. contained just two alleles - normal (straight) and "forked" (bent).
the researchers set up 96 cages in their lab
they placed four adult females and four adult males of the fruit fly Drosophilia melanogaster in each
they chose individual flies to begin these experimental populations so that the frequency of the normal and forked alleles in each of the 96 starting populations was 0.5.
the 2 alleles do not affect the fitness of flies in the lab environment.
b/c of this, Kerr and Wright confident that if changes in the frequency of normal and forked phenotypes occured, they would not be due to natural selection.
after these first generation adults bred, Kerr and Wright reared their offspring
in the offspring (f1 generation) they randomly chose four males and four females - meaning that they simply grabbed individuals without regard to whether their bristles were normal or forked - from each of the 96 offspring populations and allowed them to breed and produce the next generation
they repeated this procedure until all 96 populations had undergone a total of 16 generations
the ONLY evolutionary process in this experiment = GENETIC DRIFT