Human evolution: Neanderthal Y chromosome (Introduction)

by dhw, Saturday, September 26, 2020, 11:22 (1517 days ago) @ David Turell

QUOTE: Neanderthals had smaller populations than moderns, and small populations tend to accumulate deleterious mutations, especially on the X and Y sex chromosomes. (David’s bold)

DAVID: Still sorting out our evolution. Note the bold about deleterious mutations in small populations an opposite point to small populations creating punctuated equilibrium. Lots of Darwin theory is just supposition.

Sorry, but I think you’re getting confused. Punctuated equilibrium is Gould’s theory (not Darwin’s) that speciation occurs in bursts between long periods of stasis. The opposite of Darwin’s gradualism. I thought it was already a known fact that interbreeding within small numbers is liable to produce deleterious mutations. But as you rightly pointed out on the corvid thread:

DAVID: Hominins and homos were in small population numbers before we advanced 50,000 years ago and began to build a large population. This fits Gould's concept of small isolated populations causing rapid or large evolutionary advances.

Hence my proposal that sapiens may have branched off from the apes because local conditions may have forced particular groups to descend from the trees, whereas elsewhere the apes were able to carry on as before.