A gene known to be important for brain development is more active in humans than in apes, a discovery that might have played a key role in human evolution.
The researchers also found a surprisingly large amount of genetic variation in the PDYN promoter segment among humans. The analyses showed higher differences between the different populations—which included Chinese, Papua New Guineans, (Asian) Indians, Ethiopians, Cameroonians, Austrians and Italians — than within them. Such a pattern is a signature of evolutionary selection, Wray said.
http://www.msnbc.msn.com/id/10466677/
Originally posted by Thequ1ckTake a look at the OP of this thread. It was actually yours.
My argument is not that current races differ but that we are different from
our ancesters when they left Africa. Care to argue this or didn't you read my post?
Anyway, seeing as it's you Palonka I'm prepared to argue either case.
Then come back and tell me how a generic difference between current humans and our old ancestors would explain why "Africans didn't thrive" when "compared to Asia and Europe".
Are you saying that these differences once existed and then mysteriously disappeared as brains became more uniform across races, despite populations being separate?
Originally posted by Palynka[/b]
[b]Take a look at the OP of this thread. It was actually yours.
Then come back and tell me how a generic difference between current humans and our old ancestors would explain why "Africans didn't thrive" when "compared to Asia and Europe".
Are you saying that these differences once existed and then mysteriously disappeared as brains became more uniform ac instead they became less pronounced
when measured in the context of inter-continental groups.
The OP was very generic and was answered rather well by other parties regarding
the power of industrialisation in shaping modern economies.
We then moved onto the causes of a 'giant leap' in cultural technologies and why
this took place outside of Africa.
Modern humans are, as people are so fond of pointing out, a real mixing pot of
races so the boundaries are inevitably blurred. I'm not saying that any differences
in genetic expression disappeared. I'm saying that they became contextually
less pronounced with respect to race, as variation withing inter-continental groups grew.
The link I provided you with would suggest however that some genetic regulation
patterns are still conserved to this day.
That would be the evidence you were asking for BTW.
[i]
Originally posted by Thequ1ckAgain, a genetic explanation of "why this took place outside of Africa" would suffer from the exact same criticism above.
We then moved onto the causes of a 'giant leap' in cultural technologies and why this took place outside of Africa.
As for the "evidence", you should do well to read it carefully. The difference between humans and apes mentioned is regarding 5 substitutions and NONE of these is different between human populations. The human inter-population difference is uniquely regarding a sixth substitution. (See figure 1 in the study).
Moreover, there's nothing in the study to indicate differences in neural development across populations. Even the authors claim that almost nothing is known how PDYN affects the brain.
Originally posted by PalynkaPlease bear in mind that all I have to prove here is that there is no biological
Again, a genetic explanation of "why this took place outside of Africa" would suffer from the exact same criticism above.
As for the "evidence", you should do well to read it carefully. The difference between humans and apes mentioned is regarding 5 substitutions and NONE of these is different between human populations. The human inter-population differe opulations. Even the authors claim that almost nothing is known how PDYN affects the brain.
evidence that brain structures are the not different between (continental) races.
poly(dA) based rapid amplification of cDNA ends (RACE)
This technique was used in a study to elucidate the expression of Dynorphins.
The canonical form of PDYN pre-mRNA consisting of 3 introns(junk DNA) and 4
exons coding for the full-length protein (FL1-PDYN mRNA).
The theory ties in closely with the discovery that intron sequences rather than being
'junk DNA' are actually involved in gene expression and regulation. What is interesting
about these particular sections of DNA is that becuase they are not as essential
to gene transcription, they are more likely to be subjected to short term evolution.
'The expression of minor human PDYN mRNA forms that are either spliced or contain new exons and that apparently are absent in other species, supports the notion of an association of alternative splicing in the human genome with recent evolutionary changes.'
http://www.fasebj.org/cgi/content/full/19/11/1543
Over 95 percent of DNA has largely unknown function
http://www.psrast.org/junkdna.htm
Genetic material derisively called “junk” DNA because it does not contain the instructions for protein-coding genes and appears to have little or no function is actually critically important to an organism’s evolutionary survival, according to a study conducted by a biologist at UCSD.
http://ucsdnews.ucsd.edu/newsrel/science/mcjunk.asp
Given the previous example and (I can provide many more where Intron sequences
have recently been discovered to have a significant bearing on rapid evolution).
Hand on heart now, can you say to me for sure that by using quantative analysis
of exon sequences (genes). We are able to get a truely accurate picture of how
genes are expressed accross continents?
Signs of recent evolution by natural selection are widespread across the human genome, experts say...
http://news.nationalgeographic.com/news/2006/03/0308_060308_evolution.html
Very Recent Evolution: Up To 10 Percent Of Human Genome Has Changed
A Cornell study of genome sequences in African-Americans, European-Americans and Chinese suggests that natural selection has caused as much as 10 percent of the human genome to change in some populations in the last 15,000 to 100,000 years, when people began migrating from Africa.
http://www.news.cornell.edu/stories/July07/humanAdaptation.kr.html
Originally posted by PalynkaHey, you attacked my post on there being the possibility of genetic
I stopped reading here. Hopeless.
differences in brain structure remember?
I've shown you that it is possible and that the evidence points to it still being
a much studied and elusive area of science.
At no point did I say that it did happen, just that it's possible given the
right conditions, which it is.
Originally posted by Thequ1ckI am completely open to the idea that there are differences in brain structures between races or even differences in intelligence.
Please bear in mind that all I have to prove here is that there is no biological
evidence that brain structures are the not different between (continental) races.
However, I do not believe that the rise of Europe had anything to do with such differences, nor am I convinced that there is any reason whatsoever to think that Africas current problems are in any way related to such differences, nor am I convinced that the humans who left Africa were necessarily put under evolutionary pressure to get either more intelligent or more adaptive.
It is perfectly possible that the most intelligent group of people in the world is a small tribe in Southern Africa that was being hunted by Shaka and whose more intelligent members survived.
The environmental pressures that affect the evolution of intelligence (in both directions) are just so complex that it is currently impossible to even guess at which group is most likely to have benefited the most. It is my personal belief that in most societies today low intelligence leads to higher birth rates and as a result we are probably evolving towards lower intelligence.
Originally posted by Thequ1ckDon't you really see the absurdity of arguing for a possibility (for which you have no evidence) on the basis that there is also no evidence against it?
Hey, you attacked my post on there being the possibility of genetic
differences in brain structure remember?
I've shown you that it is possible and that the evidence points to it still being
a much studied and elusive area of science.
At no point did I say that it did happen, just that it's possible given the
right conditions, which it is.
If you don't, then at least you must admit that this is not science anymore and this thread should be moved.
Originally posted by twhiteheadWhoa whoa! Hold the boat please.
I am completely open to the idea that there are differences in brain structures between races or even differences in intelligence.
However, I do not believe that the rise of Europe had anything to do with such differences, nor am I convinced that there is any reason whatsoever to think that Africas current problems are in any way related to such differen ...[text shortened]... ere necessarily put under evolutionary pressure to get either more intelligent or more adaptive.
When did I start using terms such as 'more' or 'better'? I am arguing the case
that there are differences, that is all.
Originally posted by PalynkaNo, I don't think it's absurd at all. In fact I'd go so far as to say that most, if
Don't you really see the absurdity of arguing for a possibility (for which you have no evidence) on the basis that there is also no evidence against it?
If you don't, then at least you must admit that this is not science anymore and this thread should be moved.
not all of scientific advancement has been achieved by such a process.