|
Register | Sign In |
|
QuickSearch
Thread ▼ Details |
Member (Idle past 6503 days) Posts: 3085 From: Munich, Germany Joined: |
|
Thread Info
|
|
|
Author | Topic: Neanderthals and Cro-Magnon | ||||||||||||||||||||||||||||
Quetzal Member (Idle past 5900 days) Posts: 3228 Joined: |
Here's a recent paper that discusses the bottleneck:
Gabor Marth, et al, 2003, Sequence variations in the public human genome data reflect a bottlenecked population history", PNAS 100:376-381
quote:This paper puts the 4-7 fold population decline at around 40,000 years ago. Three different tests of the data showed strong evidence of severe linkage disequilibrium in Homo sapiens, at least in Europe. Mammuthus — you’re the extinction expert. Any speculations as to cause?
|
||||||||||||||||||||||||||||
Quetzal Member (Idle past 5900 days) Posts: 3228 Joined: |
Hey Peter,
They don't really refer to population size, per se, rather population genetic variability. Given known substitution rates, they simply didn't discover nearly enough polymorphisms. What the data DID show - again based on known substitution rates - was that the apparent homogenization in Europeans (because they were using European samples) is consistent with a bottleneck traced back to around 40 kya. As Mammuthus pointed out, there could be a lot of problems with the analysis and a lot of other factors, so there's not a "smoking gun" necessarily. It might be indicative, however, if other evidence is discovered. The article concludes with fairly high confidence on the part of the authors.
|
||||||||||||||||||||||||||||
Quetzal Member (Idle past 5900 days) Posts: 3228 Joined: |
But we didnt become extinct
Yeah, but it sounds like if the authors were right, the Europeans came pretty close. Might be that the only thing preventing it was the fact that they WERE small-scale hunter-gatherers. IOW, lots of local population extinctions homogenizing the gene pool followed by slow recovery. Just like cheetahs and elephant seals... Hmmm, Paleolithic warfare. Sounds like the bloody Europeans haven't changed much in 40,000 years. As far as neanderthalensis still living in Europe - have you seen pictures of Ken Ham? Talk about living proof that australopithecus still exists...
|
||||||||||||||||||||||||||||
Quetzal Member (Idle past 5900 days) Posts: 3228 Joined: |
Thanks for the links. I'd read the first article before. I'd like to point out that the reference I cited was from this past January, so might be either a more definitive study OR simply the next shot across the bows in the GoE/OoA war.
quote:My reference didn't dispute this - and in fact discussed the problems with previous studies in much the same fashion. All they tried to show was that there WAS evidence, based on SNPs, that there may have been a bottleneck in European populations - the population from which came the samples. They made no conclusions about whether this represented ALL human populations, or simply the geographical population based in Europe. So, IMO, they weren't trying to get in on the other debate. I'm relatively impressed with the way they handled and presented the data - since it was based on sequences derived from the Human Genome Project, they weren't actually in the lab. And they made a pretty good case for the way they chose and manipulated the data. Not conclusive, of course, but pretty indicative. quote:This is probably a pretty valid conclusion. After all, various populations - even widely distributed across continental Europe, for instance - could easily have suffered a genetic bottleneck without effecting other regional populations in the slightest. And the debate goes on... [This message has been edited by Quetzal, 05-20-2003]
|
||||||||||||||||||||||||||||
Quetzal Member (Idle past 5900 days) Posts: 3228 Joined: |
M: Have not seen Ken Ham...but given some of the posts I have read on this site I wonder that certain not to be named individuals can walk on their knuckles and type at the same time Ah, you don't know what you've been missing. Presented for your edification: Ken Ham, founder, president, and CEO of Answers in Genesis (and living proof that Australopithecus robustus still lives - or alternatively, the close relationship between Pan and Homo):
|
||||||||||||||||||||||||||||
Quetzal Member (Idle past 5900 days) Posts: 3228 Joined: |
This ought to light some fires! Everybody from taxonomists (Pan into Homo), to anthropologists with their favorite subspecies/species, to fundies with the "I ain't related to no monkey". Whee! Fun times were had by all...
I personally always thought that chimps should have been in the same genus as humans, but of course no one ever listens to me...
|
||||||||||||||||||||||||||||
Quetzal Member (Idle past 5900 days) Posts: 3228 Joined: |
Weeelll, I don't know about "all the data". Certainly a number of the references I've read seem to indicate that. As to the discussion of "European" (vs everybody else - and whatever the hell that means), I'm only going by what the authors state:
quote:Which is about all they say on the subject, actually. Here are the references quoted in the above paragraph, in case you want to look 'em up (some of them are probably on-line): 26. Reich, D. E. , Cargill, M. , Bolk, S. , Ireland, J. , Sabeti, P. C. , Richter, D. J. , Lavery, T. , Kouyoumjian, R. , Farhadian, S. F. , Ward, R. , et al. (2001) Linkage disequilibrium in the human genome Nature 411, 199-204 27. Weber, J. L. , David, D. , Heil, J. , Fan, Y. , Zhao, C. & Marth, G. T. (2002) Human diallelic insertion/deletion polymorphisms Am. J. Hum. Genet. 71, 854-862 28. Kimmel, M. , Chakraborty, R. , King, J. P. , Bamshad, M. , Watkins, W. S. & Jorde, L. B. (1998) Signatures of Population Expansion in Microsatellite Repeat Data Genetics 148, 1921-1930 29. Pereira, L. , Dupanloup, I. , Rosser, Z. H. , Jobling, M. A. & Barbujani, G. (2001) Y-Chromosome Mismatch Distributions in Europe Mol. Biol. Evol. 18, 1259-1271 30. Goldstein, D. B. & Weale, M. E. (2001) Population genomics: linkage disequilibrium holds the key Curr. Biol. 11, R576-R579 31. Gabriel, S. B. , Schaffner, S. F. , Nguyen, H. , Moore, J. M. , Roy, J. , Blumenstiel, B. , Higgins, J. , DeFelice, M. , Lochner, A. , Faggart, M. , et al. (2002) The Structure of Haplotype Blocks in the Human Genome Science 296, 2225-2229 32. Miller, R. D. , Taillon-Miller, P. & Kwok, P. Y. (2001) Regions of low single-nucleotide polymorphism incidence in human and orangutan xq: deserts and recent coalescences Genomics 71, 78-88
|
||||||||||||||||||||||||||||
Quetzal Member (Idle past 5900 days) Posts: 3228 Joined: |
Hi Mammuthus.
Can't the contamination problem apply to just about any "old" DNA experiment? I think you brought this up as your argument questioning the validity (during one of the interminable Borger discussions) of the Mungo Lake data. Is there some way to prevent contamination? How do you tell a "real" from a "contaminated" sequence? (In words of one syllable or less for all us non-molecular biology types... )
|
|
|
Do Nothing Button
Copyright 2001-2023 by EvC Forum, All Rights Reserved
Version 4.2
Innovative software from Qwixotic © 2024