BIOL 428 Chapter Notes - Chapter 44: Protein Folding, Lake Tanganyika, Zebra Finch
29 Jan 2013
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Experiment: hypothesis: having well-developed ornamental traits signals vigor and health, carotenoids are antioxidants and part of the immune system. Males in good health will have brighter bills. Zebra finch bills are bright red because of carotenoids in their diet. because they need to allocate fewer carotenoids to immune function. Zebra finch males were fed diets with and without carotenoids. How is genetic variation maintained within populations: genetic drift, stabilizing selection, and directional selection all tend to reduce genetic variation within an animal population, however, most species have considerable genetic variation. Things that help maintain genetic variation: sexual reproduction. Populations in different (varying) environments frequency-dependent selection. Sexual recombination generates new combinations of alleles on which natural selection can act. It expands variation in a trait influenced by alleles at many loci by creating new genotypes. Damage on one chromosome can be repaired by copying intact sequence on the other chromosome.
