AP Bio_genetic_variation
Subject:
Biology [1]
Genetic variation produced in sexual life cycles contributes to evolution * Mutations (changes in an organism?s DNA) are the original source of genetic diversity * Mutations create different versions of genes called alleles * Reshuffling of alleles during sexual reproduction produces genetic variation Origins of Genetic Variation Among Offspring * The behavior of chromosomes during meiosis and fertilization is responsible for most of the variation that arises in each generation * Three mechanisms contribute to genetic variation: ? Independent assortment of chromosomes ? Crossing over ? Random fertilization Independent Assortment of Chromosomes * Homologous pairs of chromosomes orient randomly at metaphase I of meiosis