The human sex test in forensic multiplexes is based on the amelogenin gene on both the X and Y chromosomes commonly used in sex genotyping. In this study of 338 male individuals in a Malaysian population comprising Malays, Chinese and Indians, using the AmpFlSTR Profiler Plus kit, the amelogenin test gave a significant proportion of null alleles in the Indian ethnic group (3.6% frequency) and 0.88% frequency in the Malay ethnic group due to a deletion of the gene on the Y chromosome. This sex test also failed in a forensic casework sample. Failure of the amelogenin test highlights the need for more reliable sex determination than is offered by the amelogenin locus in the Malay and Indian populations. The gender of the Indian-Malay amelogenin nulls was confirmed by the presence of three Y-STR alleles (DYS438, DYS390 and DYS439). For the Indian ethnic group, one of the Y-STR forms a stable haplotype with the amelogenin null. The amelogenin-deletion individuals also showed a null with a male-specific minisatellite MSY1, indicating that a very large deletion was involved that included the amelogenin and the MSY1 loci on the short arm of the Y chromosomes (Yp).
Sex determination of livestock is performed to achieve the objectives of livestock breeding programmes. Techniques for sex determination have evolved from karyotyping to detecting Y-specific antigens and recently to the polymerase chain reaction (PCR), which appears to be the most sensitive, accurate, rapid and reliable method to date. In this study, a PCR-based sex determination method for potential application in goat breeding programmes was developed. Primers were designed to amplify a portion of the X amelogenin gene (Aml-X) on the X chromosome to give a 300 bp product and Sry gene on the Y chromosome to give a 116 bp product. PCR optimization was performed using DNA template extracted from a whole blood sample of Jermasia goats (German Fawn x Katjang) of both sexes. It was possible to identify the sex chromosomes by amplifying both male- and female-specific genes simultaneously in a duplex reaction with males yielding two bands and females yielding one band. The Aml-X primer set, which served as an internal control primer, did not interfere with amplification of the Y-specific sequence even when a low amount of DNA (1 ng) was used. The duplex reaction subjected to a blind test showed 100% (14/14) concordance, proving its accuracy and reliability. The primer sets used were found to be highly specific and were suitable for gender selection of goats.