[quote name='jason777' date='Nov 25 2008, 02:27 PM']Heres some relevant data everyone else might consider including.
If paternal mitochondria was recombined with maternal it would greatly inflate the age,given the original assumption that all mitochondrial dna is maternal.
Heres some evidence of that.
First, let us examine the assumption that mtDNA is derived solely from the mother. In response to a paper that appeared in Science in 1999, anthropologist Henry Harpending of the University of Utah lamented: Ã¢â‚¬Å“There is a cottage industry of making gene trees in anthropology and then interpreting them. This paper will invalidate most of thatÃ¢â‚¬Â (as quoted in Strauss, 1999, 286:2436). Just as women thought they were getting their fair shake in science, the tables turned. As one study noted:
Women have struggled to gain equality in society, but biologists have long thought that females wield absolute power in a sphere far from the public eye: in the mitochondria, cellular organelles whose DNA is thought to pass intact from mother to child with no paternal influence. On page 2524 however, a study by Philip Awadalla of the University of Edinburgh and Adam Eyre-Walker and John Maynard Smith of the University of Sussex in Brighton, U.K. finds signs of mixing between maternal and paternal mitochondrial DNA (mtDNA) in humans and chimpanzees. Because biologists have used mtDNA as a tool to trace human ancestry and relationships, the finding has implications for everything from the identification of bodies to the existence of a Ã¢â‚¬Å“mitochondrial EveÃ¢â‚¬Â 200,000 years ago (Strauss, 286:2436, emphasis added).
One year later, researchers made this startling admission:
Mitochondrial DNA (mtDNA) is generally assumed to be inherited exclusively from the motherÃ¢â‚¬Â¦. Several recent papers, however, have suggested that elements of mtDNA may sometimes be inherited from the father. This hypothesis is based on evidence that mtDNA may undergo recombination. If this does occur, maternal mtDNA in the egg must cross over with homologous sequences in a different DNA molecule; paternal mtDNA seems the most likely candidateÃ¢â‚¬Â¦. If mtDNA can recombine, irrespective of the mechanism, there are important implications for mtDNA evolution and for phylogenetic studies that use mtDNA (Morris and Mightowlers, 2000, 355:1290, emphasis added).
In 2002, a study was conducted that concluded:
Nevertheless, even a single validated example of paternal mtDNA transmission suggests that the interpretation of inheritance patterns in other kindreds thought to have mitochondrial disease should not be based on the dogmatic assumption of absolute maternal inheritance of mtDNAÃ¢â‚¬Â¦. The unusual case described by Schwartz and Vissing is more than a mere curiosity (Williams, 2002, 347:611, emphasis added).
And now we know that these are more than small Ã¢â‚¬Å“fractionalÃ¢â‚¬Â amounts of mtDNA coming from fathers. The August 2002 issue of the New England Journal of Medicine contained the results of one study, which concluded:
Mammalian mitochondrial DNA (mtDNA) is thought to be strictly maternally inheritedÃ¢â‚¬Â¦. Very small amounts of paternally inherited mtDNA have been detected by the polymerase chain reaction (PCR) in mice after several generations of interspecific backcrossesÃ¢â‚¬Â¦. We report the case of a 28-year-old man with mitochondrial myopathy due to a novel 2-bp mtDNA deletionÃ¢â‚¬Â¦. We determined that the mtDNA harboring the mutation was paternal in origin and accounted for 90 percent of the patientÃ¢â‚¬â„¢s muscle mtDNA (Schwartz and Vissing, 2002, 347:576, emphasis added).
Ninety percent! And all this time, evolutionists have been selectively shaping our family tree using what was alleged to be only maternal mtDNA!
As scientists have begun to comprehend the fact, and significance, of the Ã¢â‚¬Å“deathÃ¢â‚¬Â of mitochondrial Eve, many have found themselves searching for alternatives that can help them maintain their current beliefs regarding human origins. But this recombination ability in mtDNA makes the entire discussion a moot point. As Strauss noted:
Such recombination could be a blow for researchers who have used mtDNA to trace human evolutionary history and migrations. They have assumed that the mtDNA descends only through the mother, so they could draw a single evolutionary tree of maternal descentÃ¢â‚¬â€all the way back to an African Ã¢â‚¬Å“mitochondrial Eve,Ã¢â‚¬Â for example. But Ã¢â‚¬Å“with recombination there is no single tree,Ã¢â‚¬Â notes Harpending. Instead, different parts of the molecule have different histories. Thus, Ã¢â‚¬Å“thereÃ¢â‚¬â„¢s not one woman to whom we can trace our mitochondria,Ã¢â‚¬Â says Eyre-Walker (1999, 286:2436, emphasis added)
www.trueorigin.org/mitochondrialeve01.asp - 38k
Now we have evidence why the age is higher than ~4,300 years ago.
I know there's paternal inheritance of mtDNA, and it's quite common in some animals. In humans, it appears to be very rare, as there's only one confirmed case that I know of. It may be in the region of one in 10,000 transmission events, like one study I know of in mice.
It's a good idea on your part, but it doesn't really help you much. Remember that the surveys we're discussing identified 14 single mutations in 1221 transmission events. This is like 14 children out of 1221 having a single difference from their mothers. The rate is one single change in 87. There was no evidence of any change due to paternal leakage.
Now, we're only about 300 generations away from Eve in your model. Tracing anyone's maternal line back to Eve, you would have had an average of one mutation every 87 generations, giving an average of about 4 for each of us, therefore an average of eight differences between random individuals. Only a small minority would have a paternal transfer of DNA in our lineages (1 in 30 if it's a one in 10,000 happening, and remember, nearly all of the father's mtDNA would be identical to the mothers).
So, you don't have enough generations to account for the difference between random individuals, which should average 8 (4 ancestral mutations each) but I think is something like 50.
Then you have the further problem of negative selection and hotspots, which count against you.
The conclusion is that homo sapiens, on the present known evidence relating to current mtDNA mutation rates and modern diversity, cannot be 6,300 years old as a species, and would have to be older than ~17,000yrs unless negative mutations in mtDNA are extremely rare and there are no significant mutation hotspots.
Here's the pdf on the rates written in full for easy copying/pasting, and the link again. (About 10 seconds to download on broadband). I've got some interesting stuff on mtDNA hotspots, as well, but I'll save it for later.
(ignore bracketed words!)http://www.pubmedcen...10&blobtype=pdf
Incidentally, Jason, putting quote and /quote in [brackets] like that gives you the quote boxes on this site. And [quote=charlie] at the beginning gives the person's name.