ANT 1 Lecture Notes - Lecture 6: Zygosity, Genetic Drift, J. B. S. Haldane
Document Summary
Challenges to darwin"s ideas: blending eliminates genetic variation evolution beyond initial distribution. Let"s return to the issue of blending: we have seen (with mendel"s help) that one allele for each locus is inherited from each parent. Discontinuous variation (e. g. , yellow or green peas) no intermediate cases (i. e. , complete dominance) Darwin thought evolution worked by the accumulation of small changes (i. e. , continuous variation) The modern synthesis (~1920-1950) reconciled mendel and darwin. Population genetic work of ra fisher, jbs haldane, and sewall wright. Continuous traits are affected by genes at many loci. Each locus has a small effect on phenotype. The modern synthesis (synthetic theory of evolution: darwin"s theory of natural selection, mechanism of inheritance (mendel, how variation is maintained, mechanisms for speciation (next lecture) Incomplete dominance: mixture of both alleles expressed in heterozygote phenotype. Normal-sized wolves carry some alleles for small (-) and some for large (+) body size. Many different genotypes lead to the same phenotype.
