抄録
We attempted to determine the sex by polymerase chain reaction (PCR) in single bovine blastomeres at the 8-cell stage. PCR was performed on male-specific primers attached to a bovine embryonic sex determination kit, an XY Selector. Embryos at the 8-cell stage were isolated by the EDTA method, and one (1/8 embryo), two (2/8 embryo), and four (4/8 embryo) blastomeres were subjected to PCR. The detection rates for male-specific PCR product were 25.8, 25.8 and 45.2% for 1/8, 2/8 and 4/8 embryos, respectively. In some embryos, despite detection of the male-specific product in 4/8 embryos, the male-specific product was not detected in 1/8, 2/8 or both 1/8 and 2/8 embryos derived from the same embryo (3.2, 3.2 and 16.1%, respectively). Collecting single blastomeres by the extrusion method affected neither the rate of development to blastocysts nor the number of cells in blastocysts. PCR was performed in 1/8 embryos collected by the extrusion method, and the male-specific PCR product was detected. Nevertheless, in 27.5% of embryos, despite detection of male-specific PCR product in 7/8 embryos, the male-specific product was not detected in the 1/8 embryo from the same embryo. These findings indicated that collecting single blastomeres at the 8-cell stage allows the selection of the male embryo by PCR, and also the extrusion method is useful for biopsy of embryo at the 8-cell stage.
