BIOL 1004 Study Guide - Mutation, Genetic Recombination, Directional Selection
Document Summary
Ultimate source of variation that serves as raw material for evolution. In multicellular organisms: only mutations in cells that produce gametes can be passed down to offspring and affect a population"s genetic variability. Sometimes a mutant allele can improve the adaptation of an individual to its environment and increase its reproductive success, but if the mutation affects a protein"s function, this will be harmful. Duplication of a gene or small pieces of dna through errors in meiosis can provide an important source of variation. If a repeated segment of dna can persist through generations, mutations in duplicated genes may accumulate, producing new genes with novel functions. Traits such as speed or strength can lead to a greater fitness. adaptations - diverse modifications that individuals of a common ancestor accumulate over millions of years. positive adaptations can increase an individual"s reproductive success. Crossing over creates recombinant chromosomes having a combination of genes that were originally on different homologous chromosomes.
