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No. 93: May-Jun 1994

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Molecular clock places humans in new world 22,000-29,000 bp

This is welcome news for anomalists who have been searching for a way to demolish the 12,000-BP (years Before Present) barrier erected across the Bering Land Bridge by the archeological establishment. But don't uncork the champagne yet, because molecular clocks are not like Big Ben.

Here's what has happened: A. Torroni and some colleagues at Emory University have analyzed the mitochondrial DNA (mtDNA) of members of seven linguistically related tribes in Central America called the "Chibcha speakers." Assuming that the homogeneous group separated from the other Amerind tribes 8,000-10,000 years ago, the Emory group found that their mtDNA had mutated at the rate of 2.3-2.9% per million years. (Note: this works out to 0.0022-0.0029% per thousand years -- a very small amount to measure accurately!) Next Torroni et al measured the mtDNA of 18 other tribes throughout the Americas and, using the mutation rate just mentioned, computed how long ago these peoples had diverged from a common ancestor. The result: 22,000-29,000 years ago. The Emory study was published in the February 1, 1994, issue of the Proceedings of the National Academy of Sciences.

All this is very well, but suppose that the tribes had split from that common ancestor before they even crossed the Bering land bridge into the New World, thereby starting the molecular clock too early? Or, perhaps Southeast Asians arriving by boat tossed sand into the gears of the vaunted molecular clocks?

So, be careful with this apparent anomaly. Molecular clocks are tricky.

(Holden, Constance; "Early American Gene Clock Gains Time," Science, 263: 753, 1994. Also: Anonymous; "DNA Dates for First Americans," Science News, 145:126, 1994.)

From Science Frontiers #93, MAY-JUN 1994. 1994-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987