Wednesday, September 22, 2010

Did Clothing Make Us Smarter? Part 2

As it turns out, the answer is "perhaps".  PBS re-ran a truly awe-inspiring program last night as part of their celebration of Darwin's 200th birthday last year and guess what?  There is strong evidence that what (brain size) separates us (humans) from our nearest bipedal relative (chimpanzees) may be the result of a single gene mutation, as I suspected in Part 1 a few weeks ago.  In a nutshell, the gene that causes our major jaw closing muscle to grow is broken to the extent that ours stop growing long before a chimpanzee's does.  The theory is that these humongous chimp jaw muscles need a solid braincase to anchor them so chimp cranial sutures (between skull bones) fuse at a much earlier age (around 3 or 4), thus limiting the space available for gray matter.  In humans, our jaw muscles are much weaker - thus allowing our braincase to continue expanding, sometimes to age 30 or so.  There you go: bigger braincase, bigger brain - we get the world, you get bananas at the zoo.  Thank you PBS.  Now we just need to find the source of that gene mutation.  Fur loincloths are as good a source as any other candidate right now in my books.  And, dear reader, you can take off that extra pair of gonch you've been wearing in an effort to cause more gene mutations - you wouldn't want to undo this particular one!