Cross-Species Sex Identification and Comparative Analysis of the SRY Gene in American Mammals

In zoo husbandry and wildlife conservation, accurate sex identification is critical for American mammals with indistinct sexual dimorphism, yet relevant molecular studies are limited. In this study, the Y-chromosomal SRY gene, a core male sex-determining factor in mammals, was investigated. Primers were designed for its conserved regions, and PCR amplification, sequencing, and bioinformatic analysis were conducted on seven Neotropical mammals (e.g., two-toed sloth, jaguar). Their SRY nucleotide sequence similarity reached 83.2–95.0%. Over 60 American mammals from Carnivora, Xenarthra, Primates, Artiodactyla and Rodentia were further analyzed via GenBank data: a phylogenetic tree was built, primer binding sites were predicted, and the target fragment was found to have purifying selection (dN/dS = 0.352) and span three HMG-box motifs. This study provides a potential cross-species sex identification method for American mammals, offering molecular support for precise zoo management and wild conservation, with important practical and scientific value.