I think the biggest difference in terms of why we sit in skyscrapers or have telephones
is our ability for culture, and by that also our ability to have
speech and language and communication.
Somewhere the groundwork for that is laid down in our DNA.
One of the big questions is where in our genome--which genes changed--
and made this human special condition possible, this human niche you have.
One particular piece in the genome, where we think something interesting happened,
is a gene called FOXP2.
FOXP2 was found as the first gene to be important for speech and language.
If you have just . . . normally everybody has two normal copies of FOXP2.
If you have just one functioning copy of FOXP2,
you have problems in speech and language development.
The movements that are necessary when you speak,
especially if you speak fast or speak complicated words, this coordination is not perfect.
So one knows it affects neural circuits in the brain that are important for language.
We've found that this gene changed suspiciously fast since we split from the chimpanzees.
We started out actually by studying this gene in the mouse,
because at that time the mouse genome was not known.
And what we found was that the protein encoded by the mouse gene
was incredibly similar to the human's.
Out of 715 amino acids that make up this protein,
there are only three differences to the mouse.
When we compared this gene to the one of the chimps and of the apes,
was that of those three differences to the mouse,
two had actually appeared since we separated our race from the common ancestor with the chimp.
And we actually see a signal in our genome around that area where those changes are
that's an indication of positive selection, meaning that some change there in the past
really made a difference for our ancestors--made them survive better,
or have more offspring in the next generation, so that all modern humans carry these two changes.
It's very tempting, of course, to get very enthusiastic and say that these two amino acid changes
then led to fully articulate modern speech.
But, of course, we should be careful.
We know that strong positive selection hit this gene rather recently in our history.
What we do not know, what is just a sort of hypothesis,
is that this positive selection had to do with language and speech.
It is perhaps the most plausible hypothesis at the moment,
since that's a major function of the gene that we know of, but it is by no ways proven.