Possible news on evolution of human brain

[j d worthington]

********

 

[Paige Turner]

interesting…

 

[j d worthington]

Sorry, folks. Was having serious problems with getting the link to work, and got frustrated; go to Yahoo news. AP story titled "Scientists find brain evolution gene"... there's also an article in Nature covering this, I understand, though I've not seen it. However, if anyone else has more information on this, I'd be obliged...

 

[littlemissattitude]

Is this the article you were referring to, j. d.?

That is very interesting. But the unusual nature of the changes - the gene in question seems to have evolved 70 times faster, according to the article, than the rest of the human genetic code and left us with 18 differences in that gene between humans and chimps, where there is only one difference between chimps and chickens - means that there will have to be very concrete evidence of this happening before it will gain acceptance by the scientific establishment.

I find it fascinating that one researcher not associated with the study team attributes the rapid changes, if they occurred as this finding suggests, to the human transition to bipedalism. That, if I recall correctly, is the current idea - that upright walking came before the expansion of the brain and probably had a role in that expansion.

I imagine that the creationists will latch on to this report, without a lot of supporting evidence being supplied, and interpret it as an evidence of divine intervention in human development.

I would like to see some more detailed information on the study that produced this new finding. Thanks for mentioning it.

 

[j d worthington]

Yep. That's the one... and why on earth I could only get the link to work sporadically, I have no idea.... something over here is seriously wonky... But thank you for providing the link.

Yes, I noticed the holes here... but it opens up some fascinating possibilities for research; and I, too, understand that the current favorite is the idea that bipedalism preceded brain expansion. Though I also understand that there are serious questions with this, it seems to have the most evidence behind it.

As for the creationists jumping onto this... depends on the stripe of creationists, I suppose. Those around here are unlikely to have anything to do with it, since they continue to deny any link between humans and other primates. But those who accept evolution as a process that gets tinkered with by some form of "intelligent design" are, indeed, quite likely to...

 

[littlemissattitude]

The creationists I know will likely just skip over the "18 differences with chimps" part and go directly to "it was so fast, God must have done it." And, of course, there will be those other folks that will see evidence there of the aliens tinkering with the brain. That's why I wish that the press would quit assuming that we are all scientific illiterates and put more particulars in their science stories.

 

[j d worthington]

Agreed.

 

[Marya]

Here is the news in Nature (with the link to the actual journal article)

http://www.nature.com/nature/journal/v442/n7104/full/442725a.html

I really hope you can get to it. I'm online with my UC account and they have a subscription to Nature but it may block others.

 

[Carolyn Hill]

I'm online with my UC account

My brain being insufficiently evolved and still rather chimplike, I latch on to only one thing: Marya, which UC?

 

[Marya]

at Davis.

 

[Carolyn Hill]

Cool! Berkeley, me. And one of my best friends is a Davis alum.

 

[dreamwalker]

who cares what the creationists think?

If aliens landed on earth, the god fearing public would soon figure out how to spin the event to fit there believes

 

[genisis2]

That one gene didn't exist until 300 million years ago and is present only in mammals and birds, not fish or animals without backbones. But then it didn't change much at all. There are only two differences in that one gene between a chimp and a chicken, Haussler said.
But there are 18 differences in that one gene between human and chimp and they all seemed to occur in the development of man, he said.

I was fascinated by this part in the article. Amazing.

 

[kyektulu]

Very interesting, thanks for the post.

 

[chrispenycate]

Mammals and birds; split before the dinosaurs, (since proto-mammals already existed) yet no lizard species carry it. Surely they mean a "gene complex" rather than a single gene (no, I've noticed the point that "science reporters" are chosen to have no knowledge of the subjects they're reporting on. I used to believe this was to prevent them going over to the enemy, but my cynicism has worn down with time, and now think editors want guarantees that the final digest is well enough chewed that their readership can't choke on it; and understandind the subject interferes with this puréeing)
On the other hand, rapid evolution suggests an incredibly high attrition rate (and a correspondingly high birth rate; our distant distaff grannies must have been shelling them out) Humanity must have been continuously on the edge of extinction for tens of thousands of years (oh, yes, I am glad we made it, even if humanity has made a few mistakes; I wouldn't have met you lot otherwise)

 

[littlemissattitude]

Humanity must have been continuously on the edge of extinction for tens of thousands of years

Well, yes. In fact, as far as I am aware current theory proposes that there was a bottleneck at one point (I can't recall exactly how long ago it was supposed to have been; I think estimates differ) at which the human population on earth narrowed down to such a low number that it was a very close thing as to whether we would survive or not. I think that is the point where those who propose the existence of a mitochondrial Eve (actually a small breeding group rather than one single female ancestor to us all) locate her/them in time.

The thing that I find interesting about all this genetic/chemical evidence concerning human evolution is that there is now a feeling that there was also a "single" (or small group of) male ancestor(s), but he is located at a different point in time (last I heard) than mitochondrial Eve. Could be, but it seems a bit counterintuititive to me.

 

[Milk]

In Matt Ridley's book it was almost as if he was saying that humans are like a race of clones. That the most 'different' humans on the earth, genetically, are far more similiar then any two members of most other species. This suggests a bottleneck., like what happened to Leapards. I hope I wasnt misunderstanding the chapter he spoke about this, because I thought it was neat. From this book on the link.


http://www.amazon.com/gp/product/0060932902/?tag=brite-21


Below is my guess on how the rapid divergence from apes happened.

The climate changed
Less trees were around.
Less trees to climb.
Proto humans became bipedal as a result.

Our diet changed to incorporate scavenging dead animals.
Being bipedal allowed us to see farther on grassy plains. Which gave us a really good advantage in scavenging the dead.
It also freed up two limbs to poke into swollen antelope bellies, and get to the bugs or brains inside, or whatever it was we ate back then.

We lost our hair as an adaptation to scavenging. Just like the vultures lost the feathers around their necks and heads. We also develop sweat glands since we are in the sun a lot more.

Changing our diet to decaying meats exposes us to a host of new micro-organisms and larger parasites.

This new soup of virus, bacteria and parasite that we are now exposed to speeds up our divergence from apes at break neck speed, since not only do these new diseases and parasites kill us, but some of them actually rewrite our code.