The sex of embryos was determined by the polymerase chain reaction (PCR) method using the DNA fragment of a sex-related gene or Y-chromosome specific nucleotide sequence. By using the DNA fragment of the human sex determinant (SRY), cells of male humans, rabbits, rats, mice and goats can be distinguished from the female cells of each animal. By PCR using DNA of the mouse sex determinant (Sry), male cells of mice and rats were selected from the cell population. The sex of cattle cells and goat cells could be determined by PCR using BOV97M (cattle Y-specific repeated DNA sequence). The DNA preparation of rabbit or cattle embryos was amplified by the primer of either SRY or BOV97M, and the embryonic sex was successfully determined. The sex of the embryos predicted using the H-Y antibody or sex chromosome was confirmed by PCR analysis for biopsy of the trophoblastic cells. The bovine growth hormone gene (bGH) was used as an internal standard of cattle-specific DNA fragment. High efficiency and accuracy for embryo sexing was attained from biopsied embryos. Three of the 8 (38%) biopsied embryos transferred into the recipient resulted in pregnancy, and the sex of 2 calves born was the same as expected.
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