LIFESCI 1 Lecture Notes - Lecture 4: Birth Weight, Heterozygote Advantage, Chromosome
Document Summary
Human birth weight-mortality is high for very small babies and very large babies. Artificial selection is a form of directional selection. All dogs are descended from wolves, all present day dogs are the same species. Microevolution: a change in the relative frequencies of alleles or genotypes in a gene pool over time. 80% green genes & 20% brown genes -> 60% green genes & 40% brown genes. Mechanisms of evolution: natural selection, gene flow, mutation, genetic drift, assortative mating. Each daughter cell has the number of chromosomes as the parent cell. Punnett square -> probability of genotype of the offspring. Allele frequencies remain the same from one generation to the next. If hardy-weinberg conditions are met, we can compute the frequencies of the 2 possible genotypes. This simple relationship allows us to translate between allele frequencies and genotype frequencies. Assumptions to meet hwe: no natural selection, no gene flow, no mutations, no genetic drift, random mating.
