A lack of genetic variation in commercially bred Nile crocodiles (Crocodylus niloticus) in the North-West Province of South Africa

Although much is known about the genetic variation of crocodilians, very li ttle is known about the levels of variation in Nile crocodiles. The purpose of this study was to compare the low levels of genetic variation reported for wild crocodile species with levels in 50 sub-adult crocodiles bred for commercial utilisation. Gene products of 52 protein-coding loci in Crocodyl us niloticus were examined by horizontal starch gel electrophoresis. No det ectable genetic variation was observed at any of. these loci, which possibl y indicates captive inbreeding or represents the natural state of the wild population where the breeding stock was captured. Possible explanations for this unexpected result are discussed.