Paabo / Oral

DNA sequence variation among apes

Henrik Kaessmann, Ingo Ebersberger, Victor Wiebe, Carsten Schwarz, Michaela Winkler, and Svante Paabo, Max-Planck-Institute for Evolutionary Anthropology, Inselstrasse 22, D-04103 Leipzig, Germany

     In order to shed light on the rate and mode of evolution of DNA sequence evolution in the germ line of humans and chimpanzees, we have sequenced a total of 180 kb of genomic DNA surrounding the ZFX and ZFY genes on the chimpanzee X and Y chromosome, respectively. The comparison of these data with the orthologous sequences in human show that whereas the ZFX region display 0.8% substitutional differences between the two species, the ZFY region display 1.5% differences. By contrast, insertions and deletions show no difference between the two regions. Interestingly, transversions show a much more drastic preponderence in the male germ line than transitions.
     While data on nucleotide sequence variation in the human nuclear genome have begun to accumulate, little is known about genomic diversity among chimpanzees. A 10,154 bp sequence on the chimpanzee X chromosome, representing all major subspecies and bonobos, will be reported. Comparison to humans reveals an almost four-fold higher diversity and a three-fold greater age of the most recent common ancestor of the chimpanzee sequences. Phylogenetic analyses show the sequences from the different chimpanzee subspecies to be intermixed and the distance between some chimpanzee sequences to be greater than the distance between them and the bonobo sequences.