The Potential and Accuracy of RNA-based Fetal Sex Determination during Early Pregnancy Using Cell-Free Fetal RNA from Korean Native Cows (Bos taurus coreanae)

Cell-free fetal RNA is useful to determine fetal sex and detect other inherent genetic disorders. However, non-invasive fetal sex determination methods using fetal RNA from maternal plasma is not yet well established in studies pertaining to bovine animals. Thus, the aim of this study was to systematically evaluate the presence of the male-specific ZRSR2Y gene transcript in maternal plasma using Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) assays, and to verify its accuracy, sensitivity, and specificity in determining fetal sex between 30 and 100 days of gestation. Overall accuracy, sensitivity, and specificity of the ZRSR2Y gene transcripts in determining fetal sex were 89.1%, 86.3%, and 100%, respectively. The 30 to 100 days of gestation were further classified into five stages of gestation, and each stage had relatively high accurate, sensitive, and specific results. Overall, these results indicate that the expression of the ZRSR2Y gene can be used for fetal sex determination in bovine animals using circulating cell-free RNA in maternal plasma during early pregnancy.