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.