BIOL 203 Lecture Notes - Lecture 5: Flowering Plant, Major Histocompatibility Complex, Allele Frequency
Document Summary
Negative am individuals choose mates different from themselves (different phenotype) Self-incompatibility in many angiosperms via s alleles encourages diversity of alleles in pop because fertilization won"t happen with the same s allele, the alleles must be different to fertilize. Occurs in humans major histocompatibility complex (mhc); mhc genes encode proteins involved in immune response. Inbreeding dispersal could be a problem (not always by choice) Leads to inbreeding depression reduces fitness; increases frequency and homozygosity of certain recessive alleles. Only way to have heterozygote offspring is that it must have at least one heterozygous parent. Can speed the rate of evolutionary change by purging exposing alleles that are deleterious recessive to natural selection (ns) Ns only individuals that survive can pass down their genes to their offspring. Sexual selection individuals leave more or less offspring based on their ability to obtain males; a special type of ns; mate quantity and quality matters. Different sexes within the same species look different.
