Neanderthals and Cro-Magnon

I know this an old topic but could you explain to me how this bottleneck 40000 yrs ago could relate to another such occurence 74000 yrs ago. The eruption of the supervolcano Toba in Sumatra, Indonesia, that is supposed to have been the cause of the last ice age according to some articles I've read.It seems to me that these events have happened fairly often in human history. Although we haven't been hit that hard by anything major in the last 10000 yrs or so.Also could you explain how one can compare DNA samples of hominids in these distant periods when DNA starts breaking down along with the tissue samples they are supposed to be taken from as soon as the being dies?Logic would dictate that after so many millenia the DNA would be corrupted beyond salvage, although I may be working under a false premise when stating the above.I'm still trying to learn the basics on this subject and it's tough without some basic explanations. Thanks for any input that you might be willng to give me.

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We are the sum of all that is, and has been. We will be the sum of our choices.

So what you're saying is that They can't recover a complete DNA sequence but only a multitude of part's of that same strand and then by using computer modelling they try to construct a DNA model of what the original strand looked like.Since these small (stable) DNA strands are broken in various places they can use various parts to rebuild the whole with high degree of confidence that what they have is the same as the original.Do I have this right or is there an error in my understanding?I've also been reading up on the different types of studies with DNA.
The 1st being aDNA which is from what I've read the explanation which you have given me, if I understood correctly, and the 2nd is mtDNA which is the type of study that is used to study the Bottleneck in human DNA Diversity which I referred to in my post.mtDNA, from what I've read is apparently the study most used due to its' reliability. Is there a site which explains the use of these different tests and their purposes that is not so technical that I wouldn't understand a word? I've been looking but can't seem to find anything that is directed toward instructing someone in laymans terms.

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We are the sum of all that is, and has been. We will be the sum of our choices.

What would, in your opinion, be the maximum age limit for a specimen, before DNA in these types of studies becomes unusable due to degradation of one type or another? ANTHROPOLOGY: DNA From an Extinct Human

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We are the sum of all that is, and has been. We will be the sum of our choices.

Well that seems to go against most of what I've been reading in relation to mtDNA studies as well as most documentaries on supervolcanoes which I've got on dvd. As a matter of fact they say in many instances that these sudden losses in population have happened at least 3 times if not more. 74 000 - 40 000 - 11 000 kyrs respectively.Since most of these studies in one way or another support the "Out of Africa" theory there may be a tendency for opponents of this theory to dilute these findings.~Again I say that I'm just learning the basics so I'm going on what I've been reading on the net as well as asking questions of those who know alot more than I.

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We are the sum of all that is, and has been. We will be the sum of our choices.

Population bottlenecks and patterns of human polymorphismToba catastrophe theoryNational Geographic, Volcanology: Big ChillDiscovery Channel feuture, SupervolcanoesLate Pleistocene human population bottlenecksHere are some of the sites I visited that give the possibility of a bottleneck in recent human history.There are also many sites saying the exact opposite. It is interesting to note that researchers cannot agree on this issue but that is due mainly to the impossibility of actually finding physical proof either way, so in the end all we are left with are a series of indicators that people use to fit one theory or the other.Since DNA studies cannot at the present time indicate whether this really happened or not, I think I'll just go by logic and accept that there were population bottlenecks in the past and that Toba was one such circumstance.I was hoping to find more conclusive proof of the matter but that does not seem to be forthcoming in the near future.The main reason that I find this logical is due to the date that mankind first appeared in its present physical form. I've heard dates ranging from 100 000 years to 50 000 years. Now taking into account that Toba straddles these values it could be concludes that the events are linked.A major decrease in population and DNA diversity will invariably cause mutations in the the population due to an insufficient gene pool. These mutations could have caused a leap in intelligence as well as physical adaptation to the cicumstances of a volcanic winter, which contributed to the start a new period of glaciation.I recently read a paper on this although I can't find the site now. It talks about genetic mutation in reduced population sizes that after the population stabilizes then become the norm for the species in question. this doesn't just apply to animals but to humans as well.Edited by Jor-el, : Forgot to add a small point to the discussion

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We are the sum of all that is, and has been. We will be the sum of our choices.

shortened linkI'm not certain but I think this is it.Edited by AdminJar, : shorten link

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We are the sum of all that is, and has been. We will be the sum of our choices.

Ok, You lost me with all the technical stuff. I'll take your word for it that the study is outdated in part. Does any new study refute the hypothesis put forward by people like Henry Harpending among others, and prove that this hypothesis is based on a flawed and false premise at this time?

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We are the sum of all that is, and has been. We will be the sum of our choices.