16 December 2018 0 3K Report

Previously it was assumed that a nonsense mutation producing a premature stop codon on KRTHAP (relating to fur loss) was only 240 000 years old (Article Human type I hair keratin pseudogene φhHaA has functional or...

). However, both the Vindija Neandertal and Altai Denisovan sequences have the stop codon as well and these divergences may be up to 700 000 ya and 1 000 000 ya, respectively. The equation Winter et al. used was:

SUBSTITUTION RATE x PAN-HOMO DIVERGENCE =

0.044×(5.5× 10^6) = 240,000

which was under the assumption that "the molecular clock has been running at the same rate in the human and chimpanzee genes."

They say, " Under this assumption, i.e., adopting the model {λh=λ, λc=1.2λ}, maximum likelihood estimates became 3.179 for λ, 0.612 for s, and 0.044 for t. It therefore appears likely that the inactivation of hHaA occurred less than approximately 0.044×(5.5× 106)=240,000 years ago. "

Redating with 1 000 000 BP we get substitution rate of:

lambda x (5.5 x 10^6) > 1 000 000 -> lambda > 0.18.

This rate gets even more problematic if we consider the divergence of head and pubic lice to 3.3 mya (Article Apes, lice and prehistory

). Body hair may have been completely lost by this date, and if so then we getting wild substitution rates.
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