ANTH 242 Lecture Notes - Lecture 7: Birth Weight, Allele Frequency, Brachydactyly
Document Summary
Tay-sachs disease: degenerative neurological disease; usually fatal by age 5 (no reproduction) High rate in ashkenazi jews-founder effect, drift: selection for recessive homozygote. Sickle cell anemia and malaria: selection on complex traits: Variation is reduced, mean stays the same. Hominid brain size: sexual selection: breeding patterns can conflict with natural selection. Things that seem disadvantageous are selected for because possessors get preferential access to mates. Genetic drift: random changes in allele frequency reduces within population diversity; increases between population variation. Founder effect: allele frequencies in an isolated population are greatly affected nu the alleles their ancestors brought into the population: penn amish-autosomal recessive disorders. Population bottleneck: due to some stochastic event, a portion of the population dies off. Gene flow: movement of genes between populations increases within population variation. One-way gene flow: genes move from population a to population b, not form b to. Genetic drift: decreases variation within populations, increases variation between populations.
