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Mutation rates in human genetics

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  • Steve Farmer
    Remember all those confident studies of population genetics from the last decade misapplied to historical periods -- e.g., in calculating the supposed date of
    Message 1 of 2 , Oct 11, 2012
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      Remember all those confident studies of population genetics from the last decade misapplied to historical periods -- e.g., in calculating the supposed date of Indo-
      European migrations, etc.?

      When these studies cropped up during the California textbook case we were the first to point out that the studies were useless since the error bars were typically + or - many thousands of years, making standard studies based on modern mitochondrial or y-chromosome studies useless when applied to population movements in historical as opposed to deep prehistorical periods.

      Despite our arguments, the papers were cranked out regularly for over a decade by well-known population geneticists. When we pointed out the problem to them they privately admitted we were right but argued that tossing in discussions of "hot" political topics in their abstracts drew needed attention (and funding!) to their work.

      We're talking about the best-known population geneticists, at Stanford and elsewhere.

      The reason for the large error bars lay as we pointed out then in large uncertainties in estimations of the mutation rates on which all these studies were based.

      It has turned out from studies conducted in the past few years that the situation was even worse than Michael Witzel and I first argued back in 2005.

      This discussion of those mutation rates, long overdue, is found in tomorrow's edition of Science magazine. Current estimations of mutation rates are roughly half the magnitude that they were when we first made those arguments back in 2005.

      All those studies from the first decade of the century (thankfully!) are now shown to be even less reliable than we argued seven years ago.

      Enjoy,
      Steve

      *******

      http://www.sciencemag.org/content/338/6104/189.summary

      Science 12 October 2012:
      Vol. 338 no. 6104 pp. 189-191
      DOI: 10.1126/science.338.6104.189

      HUMAN EVOLUTION

      Turning Back the Clock: Slowing the Pace of Prehistory

      Ann Gibbons

      Researchers have used the number of mutations in DNA like a molecular clock to date key events in human evolution. Now it seems that the molecular clock ticks more slowly than anyone had thought, and many dates may need to be adjusted. Over the past 3 years, researchers have used new methods to sequence whole human genomes, allowing them to measure directly, for the first time, the average rate at which new mutations arise in a newborn baby. Most of these studies conclude that the mutation rate in humans today is roughly half the rate that has been used in many evolutionary studies since 2000, which would make genetic estimates of dates older than previously believed. The question now is how much older?
    • Singh - Jat
      [Mod. note. The implication of the data reviewed in the new Science overview is that _all_ charts of this nature suggest a kind of precision in population
      Message 2 of 2 , Oct 15, 2012
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        [Mod. note. The implication of the data reviewed in the new Science overview is that _all_ charts of this nature suggest a kind of precision in population genetics that even in principle can't be backed by hard empirical data. You obviously can't date things within a few hundred years when your error bars are + or - many millennia, as pointed out repeatedly on the list since 2005. As the new article points out, the temporal imprecision is even worse than thought earlier. - SF.]

        Steve,

        Thanks for providing information regarding the rates of mutation. What is your opinion of this chart:� http://www.familytreedna.com/Public/r1a

        Are those dates realistic based on history and linguistic conjectures?�

        Thanks,
        Jespal Brar�

        From: Steve Farmer <saf@...>
        To: Indo-Eurasian_research@yahoogroups.com
        Cc: Steve Farmer <SAF@...>
        Sent: Thursday, October 11, 2012 9:00 PM
        Subject: [Indo-Eurasia] Mutation rates in human genetics

        Remember all those confident studies of population genetics from the last decade misapplied to historical periods -- e.g., in calculating the supposed date of Indo-
        European migrations, etc.?

        When these studies cropped up during the California textbook case we were the first to point out that the studies were useless since the error bars were typically + or - many thousands of years, making standard studies based on modern mitochondrial or y-chromosome studies useless when applied to population movements in historical as opposed to deep prehistorical periods.

        Despite our arguments, the papers were cranked out regularly for over a decade by well-known population geneticists. When we pointed out the problem to them they privately admitted we were right but argued that tossing in discussions of "hot" political topics in their abstracts drew needed attention (and funding!) to their work.

        We're talking about the best-known population geneticists, at Stanford and elsewhere.

        The reason for the large error bars lay as we pointed out then in large uncertainties in estimations of the mutation rates on which all these studies were based.

        It has turned out from studies conducted in the past few years that the situation was even worse than Michael Witzel and I first argued back in 2005.

        This discussion of those mutation rates, long overdue, is found in tomorrow's edition of Science magazine. Current estimations of mutation rates are roughly half the magnitude that they were when we first made those arguments back in 2005.

        All those studies from the first decade of the century (thankfully!) are now shown to be even less reliable than we argued seven years ago.

        Enjoy,
        Steve

        *******

        http://www.sciencemag.org/content/338/6104/189.summary

        Science 12 October 2012:
        Vol. 338 no. 6104 pp. 189-191
        DOI: 10.1126/science.338.6104.189

        HUMAN EVOLUTION

        Turning Back the Clock: Slowing the Pace of Prehistory

        Ann Gibbons

        Researchers have used the number of mutations in DNA like a molecular clock to date key events in human evolution. Now it seems that the molecular clock ticks more slowly than anyone had thought, and many dates may need to be adjusted. Over the past 3 years, researchers have used new methods to sequence whole human genomes, allowing them to measure directly, for the first time, the average rate at which new mutations arise in a newborn baby. Most of these studies conclude that the mutation rate in humans today is roughly half the rate that has been used in many evolutionary studies since 2000, which would make genetic estimates of dates older than previously believed. The question now is how much older?
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