Molecular sexing and preliminary assessment of population sex ratio of the endangered Malayan tapir (Tapirus indicus) in Peninsular Malaysia

A molecular sexing method by polymerase chain reaction (PCR) amplification of a portion of the sex-determining region Y (SRY) and the zinc finger (ZF) gene, as well as six equine Y-chromosome-specific microsatellite markers, were tested in the Malayan tapir (Tapirus indicus). While the microsatellite markers did not yield any male-specific amplicons for sex-typing, the SRY/ZF marker system produced reliable molecular sexing results by accurately sex-typing 31 reference Malayan tapirs, using whole blood, dried blood spot (DBS), or tissue samples as materials for DNA extraction. The marker system was also tested on 16 faecal samples, and the results were in general consistent with the pre-determined sexes of the animals, despite some amplification failures. A preliminary estimation of wild Malayan tapir population sex ratio was estimated from the Wildlife Genomic Resource Bank (WGRB) database of the Malaysian Department of Wildlife and National Parks (PERHILITAN), zoos, and the Sungai Dusun Wildlife Conservation Centre (WCC), as well as from the results of molecular sexing 12 samples of unknown sex. The overall sex ratio favoured females, but the deviation from parity was statistically not significant when tested using the binomial test (p > 0.05), which may be due to reduced statistical power caused by small sample sizes.