BIOLOGY 101 Chapter Notes - Chapter 23: Allele Frequency, Genetic Drift, Gene Pool
Document Summary
Genetic variation: slight differences in genes or other dna sequences among individuals: the raw material for natural selection. Discrete characters: distinct, either-or phenotypes: usually determined by a single gene. Quantitative characters: represent most of the heritable variation within a population: usually affected by one or two more gene loci. Able to measure genetic variation with both gene variability and nucleotide variability: nucleotide variability: molecular level of dna, gene variability: whole gene level. Average heterozygosity: the average percent of loci that are heterozygous: nucleotide variability measures average percent of differences in nucleotide sites in a population. Geographic variations: genetic differences in the gene pools of separate populations. Cline: a graded change in a character along a geographic range. New alleles can originate form a mutation: mutations in somatic cells of animals can be passed down to other generations. Mutations that alter the phenotype are usually harmful: point mutations occur in noncoding dna or do not change the amino acid sequence.
