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.