BI111 Chapter Notes - Chapter 66: Dna Replication, Copy-Number Variation, Disruptive Selection
Document Summary
Phenotypes (the organisms genotype) are what organisms pass onto next generation. Genetic variation: individuals in a population vary in alleles that they have for certain traits: ex. variations in snail color, flower color, human blood type, bacterial sensitivity to antibiotics. Can be caused genetically and environmentally: traits determined by environment aren"t usually passed on. Variations in traits that don"t pass to the next generation are non-heritable variations: ex. Olympic athlete has a physique reflecting lifetime of training; their child however will not have the build. Loss of genetic variation often occurs when humans deliberately select organisms with particular traits and breed them known as artificial selection: purpose is to enhance a trait (ex. production of milk in cows) Measuring genetic variation in a natural population: measure heterozygosity. Populations low in genetic diversity have lots of homozygous loci. Average heterozygosity: percentage of the gene loci that are heterozygous: useful for determining genetic variation.
