Karyotype identity of two subspecies of Eld's deer [Cervus eldi (Cervinae,Artiodactyla)] and its consequences for conservation

Among the three subspecies generally recognized within the Eld's deer (Cerv us eldi)-C. e. eldi, C. e. thamin, and C. e. siamensis--C. e, siamensis is considered to be particularly endangered following its disappearance from a major portion of its original range. The only captive breeding population of this subspecies is in the zoological parks at the Paris Museum of Natura l History. Taking into account its low effective population size (N-e = 7) and the increasing levels of inbreeding, the continued breeding of this "mi cropopulation" in isolation from closely related subspecies and in particul ar from C. e. thamin, which is much more common in toes as well as in the n ature, is questioned. As an initial step in determining ii crosses between these subspecies could be performed without risk of outbreeding depression due, in part, to gross differences in their karyotypes, a comparative chrom osome banding analysis (RBG-bands) of C, e. siamensis and C, e. thamin was undertaken. No chromosomal differences were identified between the taxa at the level of resolution obtained. The study suggests that, at least from a karyotypic perspective, no obvious differences delimit the two subspecies, and hybridization between endangered C. e. siamensis and C. e. thamin is no t likely to lead to impaired fertility in hybrid animals.