Neanderthal DNA

[Charlie Hatchett]

That cracks me up!

[Beagle]

the entire 6 billion member human species has a level of genetic diversity which is on the order of a large chimpanzee population

Beags, in this case what is considered "a large chimpanzee population"? About 2,500 breeding adults?

I don't know what they mean by the word "population" Cogs. The average troupe or group of chimps is 20-25, but can can range as high as 75 individuals. But still, no evidence of a genetic bottleneck.

It raises a question, but I don't have an answer. If either of us find one, let's post it quick.

[Digit]

I think I understand what you mean Beag when you refer to a genetic bottleneck but before I make a fool of myself (again) could you please explain?

[Beagle]

http://en.wikipedia.org/wiki/Population_bottleneck

population bottleneck (or genetic bottleneck) is an evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented from reproducing, and the population is reduced by 50% or more, often by several orders of magnitude.

In getting the answer from Wiki, it seems that there is some major disagreement about the Toba issue. Coming from Wiki, it must be substantial.

On the other hand, the Toba catastrophe theory suggests that a bottleneck of the human population occurred ca. 70,000 years ago, positing that the human population was reduced to a few thousand individuals when the Toba supervolcano in Indonesia erupted and triggered a major environmental change. The theory is based on geological evidences of sudden climate change, and on coalescence evidences of some genes (including mitochondrial DNA, Y-chromosome and some nuclear genes). The genetic evidences used in this theory seems to contradict current scientific consensus.

I'll see if I can find more on that later today.

[Digit]

Thanks Beag, I'm familiar with the theory but not the term. I remember when the idea was first promalgated on the basis that genetic diversity increases with time so the low genetic diversity of HSS could only be explained by the bottleneck.
I haven't had time to check Wiki but at the time I had my doubts as there was no evidence to suggest that other species had suffered a similar decline. As some othe species had a more specialised diet logic says that they would have suffered worse from the Toba event, or am I missing something?

[Beagle]

Digit, in my view, HSS would have been able to survive the Toba event much better than other animals. Not only was he at the top of the food chain, and omnivorous, he also made and controlled fire. Other animals had to contend with the nuclear winter without it.

[Minimalist]

Precisely.

[Digit]

Agreed, and that seems to be a fatal flaw in the theory.

[Minimalist]

Makes me wonder about all of this genetic stuff. It seems like there is a piece of the puzzle missing and they are trying to create entire theories with only a partial idea of the story.

[Digit]

It's called science Min. What has always puzzled me is that not infrequently the best brains in the business will come up with a theory that doesn't stand examination for 30 secs.
The most obvious solution to the bottleneck problem, though not necessarily the correct one, is that genetic diversity is not always linked to the passage of time.

[Minimalist]

I can buy that. Not too long ago they announced that genetic similarities had been overstated because various proteins were repeated a certain number of times or something.

It just seems that they may have jumped the gun in their degree of certainty about genetic findings. All science is about taking the work of others and building upon it.

It's something that Arch never understood about evolution....among other things.

[Digit]

Yep. The study of genetics seems to be getting more and more complex Min, and more difficult to follow as they keep expanding their dictionary.

[Minimalist]

The study of genetics seems to be getting more and more complex Min,

There's an old joke...something about

In The Beginning, there were the assumptions...and the assumptions were without form....

it went on from there. I have to see if I can find it.

[Minimalist]

That took a minute.

The Plan

In the beginning, there was the Plan.

And then came the Assumptions.

And the Assumptions were without form,

And the Plan was without substance.

And darkness was upon the face of the Workers.

And they spoke among themselves saying, "It's a crock of shit, and it stinks."

And the Workers went unto their Supervisors and said, "It is a pail of dung, and we can't live with the smell."

And the Supervisors went unto their Managers saying, "It is a container of excrement, and it is very strong, such that none may abide by it."

And the Managers went unto their Directors saying, "It is a vessel of fertilizer, and none may abide it's strength."

And the Directors spoke among themselves, saying to one another, "It contains that which aids plant growth, and it is very strong."

And the Directors went to the Vice Presidents saying unto them, "It promotes growth, and it is very powerful."

And the Vice Presidents went to the President saying unto him, "This new plan will actively promote growth, and vigor of the company with very powerful effects."

And the President looked upon the Plan, and said that it was good,

And the Plan became Policy . . .

This is how shit happens.

[Beagle]

http://www.theregister.co.uk/2007/03/26 ... ch_skulls/

Humans grew bigger brains as the climate they lived in got cooler, according to researchers at the University at Albany, New York.

The researchers concluded that humans got brainier because they had to adapt to a more challenging environment. They base this assertion on a plot of cranial capacity of 109 fossilised human skulls against the corresponding paleontological record of two million years of changing climate.

This makes some sense I guess. From the Daily Grail.