Re: Article: Hominid inbreeding left humans vulnerable to disease

From: William Morse (wdmorse_at_twcny.rr.com)
Date: 02/04/05 

Date: Fri, 4 Feb 2005 01:33:58 -0500 (EST)

"Robert Karl Stonjek" <rstonjek@bigpond.net.au> wrote in
news:ctbnni$10i8$1@darwin.ediacara.org:

> Hominid inbreeding left humans vulnerable to disease
> 12:48 25 January 2005
> Will Knight
>
> A lack of mates among human ancestors that lived million years ago has
> left modern humans more vulnerable to genetic disease, a new study
> suggests. Researchers compared samples from the genomes of more than
> 1000 people with those of chimpanzees to see how much genetic mutation
> has occurred in the two species since they diverged from a common
> hominid ancestor, about six million years ago. They also made
> comparisons with another closely related pair of species, rats and
> mice.
>
> They focused on portions of DNA close to protein-coding genes. These
> segments are thought to regulate the activation of these genes.
> The researchers calculated that these stretches of human and chimp DNA
> contained approximately 140,000 non-advantageous mutations, higher
> than expected and well above the number of retained genetic mutations
> seen in rats and mice. The mutations occur naturally but make both
> chimps and humans more susceptible to diseases with a genetic basis,
> such as cancer.
>
> Evolutionary bottleneck
>
> The researchers believe the high rate of mutations is seen because the
> hominid ancestor to both species went through an evolutionary
> bottleneck, when its breeding population was limited to only about
> 10,000 individuals.
>
> This meant that the process of pruning out damaging mutations via
> natural selection of the fittest mates was more difficult and slower.
> In contrast, rats and mice have descended from a much larger
> population, leaving them less susceptible to genetic diseases.

This makes little sense. Bottlenecks should produce inbreeding, which
should reduce heterozygosity. Bottlenecks may fix some deleterious
mutations, but 140,000?

Yours,

Bill Morse

Relevant Pages

  • Hominid Inbreeding And The Bottleneck
    ... has left modern humans more vulnerable to genetic disease, ... hominid ancestor, ... DNA contained approximately 140,000 non-advantageous mutations, ... natural selection of the fittest mates was more difficult and slower. ...
    (sci.anthropology.paleo)
  • Re: Challenge for Darwinists - Protein Synthesis
    ... mutations per diploid genome between each generation. ... ultimately 'coalesce' on a common ancestor. ... would all have the same sequence as that ancestor (this is even more ... all variation in an initially varying population will be ...
    (talk.origins)