Out Of Africa Strikes Back

[Minimalist]

http://www.eurekalert.org/pub_releases/ ... 071607.php

The Cambridge researchers studied genetic diversity of human populations around the world and measurements of over 6,000 skulls from across the globe in academic collections. Their research knocks down one of the last arguments in favour of multiple origins. The new findings show that a loss in genetic diversity the further a population is from Africa is mirrored by a loss in variation in physical attributes.

[War Arrow]

This is all getting very confusing.

[Digit]

Our genetic research shows the further modern humans have migrated from Africa the more genetic diversity has been lost within a population.

Could somebody explain that for me?

[Rokcet Scientist]

Our genetic research shows the further modern humans have migrated from Africa the more genetic diversity has been lost within a population.

Could somebody explain that for me?

I interpret that as meaning that populations furthest from Africa would show the least genetic diversity.
Whether the one is a result of the other – or vice versa! – or whether both findings are connected at all, is a conclusion I am not yet ready to accept.

[Digit]

Yeah! But as to why the greater the distance from base should reduce diversity baffles me. In fact I could make an argument that the reverse is true!

[Rokcet Scientist]

Yeah! But as to why the greater the distance from base should reduce diversity baffles me. In fact I could make an argument that the reverse is true!

Exactly. Which is why a statement like "populations furthest from Africa show the least genetic diversity" in itself doesn't indicate anything. Let alone prove anything.
But that statement does suggest a connection.

[Digit]

I know absolutely nothing about genetics other than that which I have read, so hopefully nobody will shoot the messenger.
Genetic variations are supposed to occur at regular intervals, so diversity would be determined by time, not distance. So in the post they propose a number near extinction events to account for the reduced diversity.
That might be so, let's hope they can substantiate their claim.
Equally, reduced diversity would support local evolution, and I can't see how, short of proving the extinction events, they can tell one result from 'tother.

[Rokcet Scientist]

I concur.
Without conclusive evidence, the suggestion, therefore, is frivolous.

[Digit]

And yet they tell us they are experts and we are all supposed to bow to their 'superior' knowledge.
Everytime I begin to believe these people I quote to myself, 'Piltdown Man', then the belief passes!

[Rokcet Scientist]

And yet they tell us they are experts and we are all supposed to bow to their 'superior' knowledge.
Everytime I begin to believe these people I quote to myself, 'Piltdown Man', then the belief passes!

It seems everybody who has spend some time on a subject calls him/herself an expert. Whether their points of view carry any merit or not* does not seem to count at all.

*as only third parties can determine!

[Manystones]

And let's not forget the movement of Sapien Sapien into Europe (around 100,000 years ago)still doesn't seem to confer with the "dawning of civilisation" supposedly seen around 40,000 (often quoted on the basis of Cave Art, etc.) that increasingly appears to be attributable to Neanderthal and not modern archaic humans. To my understanding this is an integral part of the "Out of Africa" theory that fails to withstand close scrutiny.

[Digit]

Or 'Clovis first' MS and lets all ignore Topper!

[Minimalist]

Geneticists have made so many claims that jumping on everything they say is getting old.

I still can't get by the selective "mass-extinction" of the Toba volcano which took out HSS but no one else.

[Digit]

Nature's own 'ethinic cleansing' Min.

[FreeThinker]

I will take a stab at this one. I believe the thinking here is that in an out of Africa model the further from Africa a population is the more recent it is chronologicly. It is due to this relative newness of these far flung populations that geneticly they exhibit less diversity than the older initial Africal populations. The thinking is that these newer populations have not had the time to become diverse. In a multiregional model where all human populations evolved from more archaic forms locally you would expect to see little or no difference in amount of genetic diversity when comparing far flung populations. In other words a uniformly old population (multiregional) would exhibit a uniform amount of genetic diversity, whereas in a population that fanned out from an initial starting point would have less and less diversity the farther (and hence younger) you looked from the initial (African) population.

Seems logical to me and is a strong argument for the Out of Africa model.