A few years ago, I referred to a fundamentalist Christadelphian website Christadelphian Answers which had made the regrettable mistake of linking the admirable goal of providing a Christadelphian apologetics site with evolution denialism. I hadn't thought of it for some time until looking at an old post on a Christadelphian forum ostensibly dedicated to evolution denialism that referenced a Christadelphian Answers article that claimed to provide a case against common descent. When I tried to look up that post, I found the link dead; evidently, Christadelphian Answers is no more. One of course must temper the sadness at a loss of a Christadelphian-specific apologetic site with the relief that another anti-evolution forum is no more.
The Internet Archive of course ensures that nothing is really lost, so it didn't take me long to find the offending article which began boldly:
Anyone familiar with evolutionary biology will of course be sadly shaking their heads at the bold assertion that "common descent is an unworkable hypothesis". Just the convergence of morphological and molecular phylogenies alone made the case for common descent, and this was recognised nearly sixty years ago as Linus Pauling and Emil Zuckerkandl who observed:
"It will be determined to what extent the phylogenetic tree, as derived from molecular data in complete independence from the results of organismal biology, coincides with the phylogenetic tree constructed on the basis of organismal biology. If the two phylogenetic trees are mostly in agreement with respect to the topology of branching, the best available single proof of the reality of macro-evolution would be furnished. Indeed, only the theory of evolution, combined with the realization that events at any supramolecular level are consistent with molecular events, could reasonably account for such a congruence between lines of evidence obtained independently, namely amino acid sequences of homologous polypeptide chains on the one hand, and the finds of organismal taxonomy and paleontology on the other hand. Besides offering an intellectual satisfaction to some, the advertising of such evidence would of course amount to beating a dead horse. Some beating of dead horses may be ethical, when here and there they display unexpected twitches that look like life." [1]
We demonstrate quantitatively that, as predicted by evolutionary theory, sequences of homologous proteins from different species converge as we go further and further back in time. The converse, a non-evolutionary model can be expressed as probabilities, and the test works for chloroplast, nuclear and mitochondrial sequences, as well as for sequences that diverged at different time depths. Even on our conservative test, the probability that chance could produce the observed levels of ancestral convergence for just one of the eight datasets of 51 proteins is ≈1×10−19 and combined over 8 datasets is ≈1×10−132. By comparison, there are about 1080 protons in the universe, hence the probability that the sequences could have been produced by a process involving unrelated ancestral sequences is about 1050 lower than picking, among all protons, the same proton at random twice in a row. A non-evolutionary control model shows no convergence, and only a small number of parameters are required to account for the observations. It is time that that researchers insisted that doubters put up testable alternatives to evolution. [2] (Emphasis mine)
Those odds alone should have prompted the author of that Christadelphian Answers article to reconsider the folly of writing an article boldly declaring that common descent was an "unworkable hypothesis" but given the PLoS One article nowhere features in the Christadelphian Answers article, I suspect the author wasn't even aware of it.
The PLoS One article is of course freely available, but for those wanting a commentary on it, there's a nice, accessible post on it at EvoGrad.
References
1. Zuckerkandl, E. and Pauling, L. (1965) "Evolutionary Divergence and Convergence in Proteins." in Evolving
Genes and Proteins: a symposium held at the Institute of Microbiology
of Rutgers, with support from the National Science Foundation. Eds Vernon Bryson and Henry J. Vogel. New York: Academic Press, 101
2. White WTJ, Zhong B, Penny D (2013) Beyond reasonable doubt: evolution from DNA sequences. PLoS ONE 8:e69924
