Molecular Divergence Times: Conflicting Studies

Different studies on the same or similar groups of molecules sometimes generate radically different spacing times, for example, Francisco Ayala and many of his colleagues recalculated the spacing times of the sequence division using the same protein-coding genes used by the Wray team.28 Correcting a "crowd of statistical problems" in Wray's study, Ayala and colleagues found that their estimates were "consistent with fossil estimates," not with the deep divergence hypothesis, and concluded that "interpolation into distant times from molecular evolutionary rates; estimation within finite data sets is risky."30 Or as Valentine, Jablonsky, and Irwin concluded: "The accuracy of the molecular clock remains problematic, at least for the divisions of the people, for estimates that vary from one another by about 800 million years depending on the techniques or molecules used." The reported precambrian divergence times would have been much different had it not been for evolutionary biologists and molecular taxonomists ignoring certain molecules in their studies to avoid dramatically contradictory results. Take, for example, histones – proteins found in all eukaryotes that contribute to the assembly of DNA into chromosomes or chromosomes – and histones show little variation from one type to another.32 They are never used as molecular clocks. Sequence differences between histones assuming that the rate of mutation is comparable to that of other proteins will generate a time-spacing that is vastly different from the studies of many other proteins33, as differences between histones produce a very recent divergence unlike other studies. Evolutionary biologists typically exclude histones from their considerations because these times do not confirm their preconceived ideas about what a precambrian tree of life should look like. - Dr. Steven Meyer. — Source: Published on Facebook's "Braheen Center" page