The Journal of Heredity 1989:80(5):377-382
© 1989 The American Genetic Association 80:377-382
research-article |
Allozyme Variation and Differentiation in African and Indian Rhinoceroses
Department of Biology University of California-San Diego, La Jolla
Department of Biology, Center for Molecular Genetics University of California-San Diego, La Jolla
Center for the Reproduction of Endangered Species, Zoological Society of San Diego
Whipsnade Park Dunstable UK
Dvur Kralove Zoological Park, Dvur Kralove nad Lebem Czechoslovakia
Address reprint requests to Dr. Woodruff, Dept. of Biology (C-016), University of California-San Diego, La Jolla, CA 92093
Abstract
We studied variation at 25 to 31 allozymic loci in African and Asian rhinoceroses. Four taxa in three genera were examined: African Ceratotherium simum simum (northern white rhinoceros), C. S. cottoni (southern white rhinoceros), Diceros bicornis (black rhinoceros), and Rhinoceros unicornis (Indian rhinoceros). Extremely small amounts of intraspecific variation were observed in sample sizes of 2 to 10 presumably unrelated individuals per taxon: 
= .00–.10, 
= 0.00–0.02. We examined demographic bottlenecks and sampling errors as possible reasons for the low levels of detectable variation. The very small intraspecific genetic distance (
= 0.005) between the two living white rhinoceros subspecies is far lees than the distance that has been reported for other mammal subspecies. The mean D value of 0.32 ± 0.11 between the two African genera was also less than expected given the divergence time of greater than 7 million years suggested by the fossil record. Rhinoceroses may be evolving more slowly at the structural gene loci than are some other mammal groups. The estimate of = 1.05 ± 0.24 for the African–Indian split supports this idea, as the lineage diverged at least 26 million years ago. Our results contribute to the currently available scientific information on which management decisions aimed toward saving endangered rhinoceroses should be based.