Tumennasan K, Tuya T, Hotta Y, Takase H, Speed R M, Chandley A C
Department of Genetics, Institute of General and Experimental Biology, Mongolian Academy of Sciences, Ulaanbaatar, Mongolia.
Cytogenet Cell Genet. 1997;78(1):69-73. doi: 10.1159/000134633.
Investigations conducted in Mongolia into the sterility of the male khainag, an F1 hybrid animal resulting from crossing cattle (Bos taurus, 2n = 60) with yaks (B. grunniens, 2n = 60), are reported. Reduced numbers of spermatogonia appear to characterise the testicular tubules of the khainag, and despite the identical cytological appearance of the two parental karyotypes, synaptic anomalies are seen at meiotic prophase in primary spermatocytes. The female khainag is fertile and can be backcrossed to cattle or yak bulls to produce a B1 backcross animal, the ortoom. Further backcrossing of ortoom females to cattle or yaks will yield a B2 backcross animal, the usanguzee. The impression is gained of better meiotic pairing in the backcross animals than in the khainag. The "Haldane Rule" is followed perfectly by the cattle x yak hybrid; namely, sterility is confined to the male.
本文报道了在蒙古国针对雄性杂种犏牛不育性所开展的研究。杂种犏牛是牛（Bos taurus，2n = 60）与牦牛（B. grunniens，2n = 60）杂交产生的F1代杂种动物。精原细胞数量减少似乎是杂种犏牛睾丸小管的特征，尽管两个亲本核型的细胞学外观相同，但在初级精母细胞减数分裂前期可见突触异常。雌性杂种犏牛可育，并且可以与牛或牦牛公牛回交产生B1代回交动物——犏雌牛。将犏雌牛与牛或牦牛进一步回交将产生B2代回交动物——犏雄牛。回交动物的减数分裂配对似乎比杂种犏牛更好。牛×牦牛杂种完全遵循“霍尔丹法则”，即不育仅限于雄性。
