Re: genetic diversity (was Newsweek)

Henry T Robertson (
14 Feb 1995 02:08:10 GMT

In article <3houm8$>,
S. LaBonne <> wrote:

>1) Exactly what is "non-genetic DNA"?

I seem to have meant non-gene DNA, according to Frosch.

>2) The "more" differences
>between humans and chimps are a _consequence_ of the genetic
>differences. Is there something about this you don't understand?

How did the differences in non-gene DNA come about? Through mutations?

>the way, there are cases of animals with different chromosome numbers
>that can interbreed, so that by itself is not an absolute barrier.)

BTW, another question: has there been observed in humans any mutations in
non-gene parts of DNA, causing a change in number of base pairs?
If so, are such mutant individuals capable of reproducing with other humans?
Would that mean that humans don't necessarily have the exact same
number of base pairs?

>3) Did you know that in principle a single base change at a single
>locus- an infinitesimally small genetic difference, that is- could be
>sufficient to establish reproductive isolation between two
>populations of very similar organisms (which thereby will have come to
>belong to different species)? And this reproductive barrier could just
>as well be _behavioral_ as physiological- even something as simple as
>a different male coat color, scent, or whatnot, that causes females of
>the other species to turn up their noses. (The "biological species
>concept" refers to absence of fertile matings _in the wild_, not in
>artificial laboratory conditions.)

Have there been any known instances of humans with a certain mutation that
rendered them physiologically incapable of mating with normal humans,
but capable of mating with other individuals with the same mutation?

>Genetics and evolution are not games that can profitably be played
>by rank amateurs.

I thought of it as an honest inquiry rather than a game actually.