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Unformatted text preview: Biological Anthropology Notes November 17, 2006- Phylogenetic implications of primate molecular data- The Molecular clock o Estimating time of branching events o How does it work? Need a well dated branching event in fossil record Split between marsupials and placental mammals - 120 million years ago o Total evolutionary distance 2x time since last common ancestor Determine measure of difference in a protein or DNA strip Example such as marsupial or placental dog Determine rate of change in protein or DNA strip Rate = measure of difference / total evol. Distance 240 nucleotide differences / 240 million years = 1 diff./1 mil. Years Apply rate of change to estimate total evolutionary distance between other organisms Human and chimpanzee o 12 nucleotide diff. in gene X o 1 diff/1 million years = 12 differences / ? o 12 million years in total evolutionary distance Time since divergence =- half total evolutionary distance o 12 million years / 2 -= 6 million years Last common ancestor between chimp and human at 6 million years o Observations on molecular data Different molecular analyses generally agree on the evolutionary relationships between species Nucleotide sequencing is more precise Human-chimp split 6-7 million years ago Rates of change are protein/DNA strip specific Rate of change for any single protein/DNA strip is constant across closely related species Molecular DNA does not replace the fossil record- Johnathan Marks and Molecular anthropology o What does genetic difference mean?...
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This note was uploaded on 04/05/2008 for the course ANTHRO 2B taught by Professor Egan during the Spring '08 term at UC Irvine.
- Spring '08
- Biological Anthropology