These selective regimes maintain polymorphism at the A locus as in a

These selective regimes maintain polymorphism at the A locus as in a

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These selective regimes maintain polymorphism at the A locus as in a multiple niche polymorphism considered in the population genetics section. These sets of fitness/mating values will result in the evolution of associations (e.g., linkage disequilibria) between the A and the B locus (e.g., AABB individuals and aabb individuals will be found in the populations with few intermediates. these have high fitness these have low fitness The green lacewings (Genus Chrysoperla ; formerly Chrysopa ) seem to exhibit patterns of host preference and mate choice similar to that presented above (studied by the Taubers, Cornell University). One form is adapted to one host/habitat and a second to another; this habitat preference appears to be controlled by a single locus with other modifying loci (some evolutionists have not accepted the lacewing data as conclusive). See the other sympatric speciation model that involves variation in a resource base (fig. 16.10, pg. 443). This model still requires the evolution of associations (e.g.,
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Unformatted text preview: linkage disequilibrium) between fitness genes and behavior genes. But, if sympatric speciation is, if not common, at least possible, is the model really sym patric?: is it just microallopatric speciation (some argue NO if adults come up off their hosts into a mating swarm, but then proceed to mate). Another crucial issue is: what is the rate of recombination between these two types of loci since crossing over will break up favorable associations. A model of host preference and assortative mating invoking many genes (polygenic model) make it more difficult to maintain nonrandom associations. A general issue with all of these models is how much gene flow is tolerated. Evolution of barriers to gene exchange is the issue, gene flow = gene exchange; how much gene flow can take place and still evolve barriers to the gene flow?? The answer depends on the genetic architecture of speciation (how many genes, how much divergence, etc.; next lecture on genetics of speciation)....
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This note was uploaded on 11/06/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.

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