Re: more brain / gene stuff

[David Marjanovic <david.marjanovic@gmx.at>]

> The beauty of the technique, according to experts, is that they did
> not have to know what the DNA was actually doing.

Yes -- but they still don't know what it's doing. :-)

> She and her colleagues first looked for bits of the genome that are nearly
> identical in the mouse, rat and chimpanzee. These shared a common ancestor
> around 80m years ago

What about 65? It all depends on the method and the calibration point(s) 
used.

> This region differs by just two changes between chimps and chickens,
> which shared a common ancestor around 310m years ago.

Certain molecular biologists believe in this date so strongly that it will 
soon end up in the textbooks. (If it hasn't already.) But *Hylonomus* and 
*Protoclepsydrops* are late Bashkirian in age, so 310 is probably an 
underestimate even of their age, when something like 5 amniote ghost 
lineages must already have existed. The actual origin of Amniota could have 
happened tens of Ma earlier -- the fossil record of the Early Carboniferous 
is too bad to even guess at an upper limit. (Erm, and *Casineria* has never 
been in a serious-sized cladistic analysis.)

> But since humans and chimps split 5m years ago

Or 6, or 7...