A RELIABLE SEX DETERMINATION ASSAY FOR BOVINE PREIMPLANTATION EMBRYOS USING THE POLYMERASE CHAIN-REACTION

We have developed a polymerase chain reaction (PCR)-based method for accurate sex determination of preimplantation bovine embryos. The method utilizes three different sets of primers in the PCR. The first pair of primers recognizes the bovine-specific satellite sequence that is amplified in both females and males. In addition, two pairs of primers recognize bovine Y chromosome-specific sequences that are amplified in males only. Duplicate embryo extracts were used in the PCR; the first sample was run in the presence of bovine-specific as well as one set of the Y chromosome-specific primers; the second sample was run in the presence of the other male-specific primers. The method has been specifically designed for screening bovine embryos. Based upon examining blood cell DNA from adult males and females, the assay is extremely accurate, as no single incorrect result has occurred yet. Missing samples were easily detected by the absence of the bovine-specific signal. The method has been used for the transfer of bovine embryos on which sex determinations have been performed.