BSC 114 Lecture Notes - Lecture 25: Selective Breeding, Meiosis, Chromosome
24 Mar 2016
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Document Summary
Duplication, rearrangement, and mutation of dna contribute to genome evolution. The basis of change at the genomic level is mutation, which underlies much of genome evolution. The earliest forms of life likely had a minimal number of genes, including only those necessary for survival and reproduction. The size of genomes has increased over evolutionary time, with the extra genetic material providing raw material for gene diversification. Accidents in meiosis can lead to one or more extra sets of chromosomes. Humans have 23 pairs of chromosomes, while chimpanzees have 24. Following the divergence of humans and chimpanzees from a common ancestor, two ancestral chromosomes fused in the human line. Duplications and inversions result from mistakes during meiotic recombination. Comparative analysis between chromosomes of humans and 7 mammalian species paints a hypothetical chromosomal evolutionary history. Duplication and divergence of gene-sized regions of dna.
