Last week I briefly posted on the claim being made by John Grehan and Jeffrey Schwartz that morphological evidence indicates that the orang is our closest living relative and that molecular evidence accumulated over the past 40 years that the chimpanzee is closer is flawed and can be discarded. A vigorous discussion ensued and is still ongoing.
Last night I posted a question that remains unanswered by the proponents of the orang claim, so I’m going to repeat it here in a little more detail to see what we can ascertain. As a starter, let’s allow the claim that the molecular methods that support the Homo-Pan clade are flawed and should be discarded. How does a supporter of the Homo-Pongo clade explain the distribution of endogenous retroviruses within the great apes, a distribution that would appear to support the closer affinity of Homo and Pan.
(Source: Lebedev, Y. B., Belonovitch, O. S., Zybrova, N. V, Khil, P. P., Kurdyukov, S. G., Vinogradova, T. V., Hunsmann, G., and Sverdlov, E. D. 2000 “Differences in HERV-K LTR insertions in orthologous loci of humans and great apes.” Gene 247: 265-277.)
Now it would appear (to me at least) that these results which are not dependent on the methods criticized by Grehan and Schwartz would unambiguously offer support for the Pan-Homo clade (and indeed the molecular phylogenies that they discard).