Hybrid zones: last example

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Hybrid zones last example

• 1. Hybrid superiority
• Artemesia tridentata (Big Sagebrush)

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Common garden experiment
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Genetics of speciation how much genetic
divergence characterizes gene pool integrity? Pea
aphids alfalfa and red clover hosts Cross
transplants between hosts reduced fitness
hybrids reduced fitness Genetic population
specific markers found Host preference related
fecundity appear to be heritable
Divergence speciation?
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6 lakes, western British Columbia Same two
species pairs
Sticklebacks
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Phylogeny
Pixt gene shared among ancestral and derived
populations Regulator suppresses its expression
in freshwater forms Variation in Eda locus
Allele causes reduction of body armor in
freshwater forms. Freshwater species isolated
by size and color cues used in mate selection
assortative mating.