Ovine fetal sex determination using circulating cell-free fetal DNA (ccffDNA) and cervical mucous secretions

ObjectiveTo use PCR to investigate the presence of fetal SRY gene in the ovine cervical secretions and maternal blood plasma, and to assess predict fetal sex at different times of gestation in the ewe.MethodsFetal DNA was isolated from blood plasma and cervical secretions of 32 pregnant ewes during the 6 to 21 week of gestation. Overall, 15 male and 17 female fetuses were included in this study. After DNA extraction, the PCR amplified a 280 bp fragment from the X-chromosome and a 217 bp fragment from the Y-chromosome based on a sex-related polymorphism in the amelogenin locus.ResultsThe presence of fetal Y-chromosome was confirmed in 11 out of 15 cervical mucus and 12 out of 15 blood plasma samples collected from sheep with male fetuses. The sensitivity and specificity of tests were 70% with false negative results.ConclusionThis is the first report on validating the presence of fetal DNA material in the ovine cervical mucus and its potential usefulness for fetal sexing.