Re: New Cytochrome C evidence
- From: r norman <r_s_norman@xxxxxxxxxxxx>
- Date: Sat, 09 Aug 2008 16:14:49 -0400
On Sat, 9 Aug 2008 12:07:04 -0700 (PDT), _Arthur
<Arthur_@xxxxxxxxxxxx> wrote:
Complete Neanderthal Mitochondrial Genome Sequenced From 38,000-year-
old Bone
http://www.sciencedaily.com/releases/2008/08/080807130824.htm
"Analysis of the new sequence confirms that the mitochondria of
Neanderthals falls outside the variation found in humans today,
offering no evidence of admixture between the two lineages although it
remains a possibility. It also shows that the last common ancestor of
Neanderthals and humans lived about 660,000 years ago, give or take
140,000 years.
Of the 13 proteins encoded in the mitochondrial DNA, they found that
one, known as subunit 2 of cytochrome c oxidase of the mitochondrial
electron transport chain or COX2, had experienced a surprising number
of amino acid substitutions in humans since the separation from
Neanderthals. While the finding is intriguing, Green said, it's not
yet clear what it means."
-------------------
Let's see how Sean Pitman spins this one. Of course, no "1000 aa"
changes were involved, so it falls under the Pitman Treshold.
The paper is
A Complete Neandertal Mitochondrial Genome Sequence
Determined by High-Throughput Sequencing
Richard E Green (and 24 co-authors)
Cell 134(3): 416-426( 8 August 2008)
"A complete mitochondrial (mt) genome sequence was reconstructed from
a 38,000 year-old Neandertal individual with 8341 mtDNA sequences
identified among 4.8 Gb of DNA generated from 0.3 g of bone. Analysis
of the assembled sequence unequivocally establishes that the
Neandertal mtDNA falls outside the variation of extant human mtDNAs,
and allows an estimate of the divergence date between the two mtDNA
lineages of 660,000 ± 140,000 years. Of the 13 proteins encoded in the
mtDNA, subunit 2 of cytochrome c oxidase of the mitochondrial electron
transport chain has experienced the largest number of amino acid
substitutions in human ancestors since the separation from
Neandertals. There is evidence that purifying selection in the
Neandertal mtDNA was reduced compared with other primate lineages,
suggesting that the effective population size of Neandertals was
small."
The "surprising number of amino acid substitutions" is four. I don't
think Pitman will be too impressed. As to the significance of these
four changes, the authors state: "However, all these substitutions are
in regions of the protein that, based on the crystal structure, do not
have any obvious function, and they are variable among primates.
Hence, they may represent either minor adaptive advantages, perhaps of
regulatory relevance, or have no significant functional consequences
for mitochondrial function."
.
- Follow-Ups:
- Re: New Cytochrome C evidence
- From: Ron O
- Re: New Cytochrome C evidence
- From: _Arthur
- Re: New Cytochrome C evidence
- References:
- New Cytochrome C evidence
- From: _Arthur
- New Cytochrome C evidence
- Prev by Date: Re: Is Elsberry on-the-run?
- Next by Date: Re: Myth Busters: Atheist Myth One that anti-Darwinism positions
- Previous by thread: New Cytochrome C evidence
- Next by thread: Re: New Cytochrome C evidence
- Index(es):
Relevant Pages
|
