ylevy@BINAH.CC.BRANDEIS.EDU (06/20/91)
While the DNA content (as determined by hybridization kinectics) of humans
and say, chimpanzees or gorillas, is very similar, the ARRANGEMENT of this
similar DNA on chromosomes is very different. Therefore, I think that were
fertilization even to take place across species (I'm not sure of the
chances that this would be successful) the chromosomes would be unable
to pair properly with their homologs and that the cross would fail.
I remember hearing of an example of two species of antelope that appeared
extremely similar to one another but could not interbreed. Upon
investigation of DNA similarity, it was found that they were related by
sequences but that what had occurred through evolution was a chromasomal
rearrangement that prevented interbreeding in the manner mentioned above.
Yaron Y. Levy
Biology Dept., Brandeis Univ.