A 38,000-year old bone has yielded the world's first complete Neanderthal mitochondrial genome sequence, offering a tantalising glimpse at the genetic changes that separate humans from Neanderthals, which split some 600 millennia ago.
Gilbert notes that Green's team went to extraordinary feats to prove that the Neanderthal sequence was unsullied by the DNA of its human handlers. Such bona fides should carry over to the complete genome, he says.
Something is wrong here. War, disease, death, destruction, hunger, filth, poverty, torture, crime, corruption, and the Ice Capades. Something is definitely wrong. This is not good work. If this is the best God can do, I am not impressed.
The mystery of what killed off the Neanderthals about 30,000 years ago comes a step closer to being solved with a study suggesting that they formed a tiny population that had been teetering on the brink of extinction.
Something is wrong here. War, disease, death, destruction, hunger, filth, poverty, torture, crime, corruption, and the Ice Capades. Something is definitely wrong. This is not good work. If this is the best God can do, I am not impressed.
In that scenario HN was simply an anomaly on the evolutionary hominid tree. With 10,000 individuals max. at any one time they would have been an unimportant sideshow, really.
Something is wrong here. War, disease, death, destruction, hunger, filth, poverty, torture, crime, corruption, and the Ice Capades. Something is definitely wrong. This is not good work. If this is the best God can do, I am not impressed.
OK Min, consider this. There is an island off the coast where I live, many years ago rabbits were introduced to the island and increased till they became a nuisance and have since had their numbers controlled.
There have been no fresh introductions since that first time, now what would DNA tell us about the numbers of such an isolated community?
Assuming that there was only one initial introduction and no other rabbits from outside I would expect very little variation...unless they did something amazingly stupid like bring in two hundred breeding pairs at the outset.
I'm also not sure what that analogy has to do with humans who were not so isolated?
Something is wrong here. War, disease, death, destruction, hunger, filth, poverty, torture, crime, corruption, and the Ice Capades. Something is definitely wrong. This is not good work. If this is the best God can do, I am not impressed.
My point Min is that any community at that time would likely to have had a relatively small gene pool. DNA from, say thirty people who had infrequent additions from outside would logically show a small number.
What would then happen if their number increased to say 100 with no significant outside additions?
I fail to see how maths can answer the question.
If they carried out a similar examination on a mainland Chinese I wonder what figure they would get then?
The report deals only with mtDNA and means nearly squat at this time. Actually, I wouldn't expect to find any similarity between HN mtDNA and HS mtDNA in the first place since the maternal direct line provides all or nothing to their progeny. If we are to get a grip on hybridization, only nuclear DNA will tell the tale. Hawks does a good job of reviewing the problem here:
"Determining whether Neandertals particularly contributed genetic material to the living human population is a challenge. Even if clear evidence of archaic lineages is found, it is difficult to substantiate that these lineages were found in a particular region of Europe over 40,000 years ago.
Yet, substantial evidence of archaic lineages has been found. There is no question that some -- perhaps most -- human genes preserve allelic variation from archaic human populations.
The morphological and archaeological evidence suggest strongly that Neandertal genetic lineages survived into later Upper Paleolithic populations. Ultimately, the genetic test of Neandertal survival may be carried out by finding nuclear DNA sequences from Neandertal fossils themselves. Until that time, we can say only that some Neandertal contribution to the modern human nuclear gene pool is consistent with the known evidence."
Minimalist wrote:Assuming that there was only one initial introduction and no other rabbits from outside I would expect very little variation...unless they did something amazingly stupid like bring in two hundred breeding pairs at the outset.
I'm also not sure what that analogy has to do with humans who were not so isolated?
If I remember ANTH101 at all, it seems to me that in Africa (origin of the species) the variation of DNA is greater than in the rest of the world where there has been greater interactions between "races". Based on this I would have to disagree and say that the DNA of such isolated rabbits would demonstrate a greater variation.
Which species RW?
I suspect that if we trace our origins back far enough then we will end up in Africa. But it would seem that some more recent species of Homo developed elsewhere, therefore the more recent, non Africans, would show less variation as they have not been around long enough to accumulate many. Unless some spontaneous mutation took place an isolated colony of Rabbits, or other species, could well be starting from a base with little variation in their gene pool, so why would there then be much variation even many years later?
Digit wrote:Which species RW?
I suspect that if we trace our origins back far enough then we will end up in Africa. But it would seem that some more recent species of Homo developed elsewhere, therefore the more recent, non Africans....
Roy.
But would non-Africans be more recent? They'd be more recent, perhaps, than the forebears that they left behind in Africa. But the African population would continue evolving, as apparently they did, producing another variant around 200,000 YA, the HSS "species" that present mtDNA traces back to (except in Australian Mungo Man).
I'm not supporting OOA over regionalism. I think that what we call "species" were actually just variations on HE, with intermixing occurring often enough to distribute new gene mixes into old gene pools, at overlapping geographical perimeters and then spreading into the separate gene pools. Once HE arrived on the scene, it might be more accurate to speak of new traits than of new "species."
Digit wrote:Could somebody explain to me how the DNA of one individual can decide the total population figure for the species?
Like Min said: math. There's nothing in those articles that claims that that number of 10,000 individuals was arrived at from the (Mt)DNA analysis. So it must have been derived from other data (which weren't mentioned in the articles).
Last edited by Rokcet Scientist on Mon Sep 28, 2009 3:57 pm, edited 1 time in total.
