BMY牛和婆罗门牛核型分析

Karyotypic analysis of BMY cattle and Brahman

【目的】观察BMY牛及婆罗门牛染色体核型,为培育我国热带肉牛新品种积累细胞遗传学基础资料和数据。【方法】采用外周血淋巴细胞培养及常规染色方法制备牛染色体标本,比较BMY牛及婆罗门牛染色体核型的差异。【结果】BMY牛和婆罗门牛染色体数为2n=60,染色体臂数（NF）=62,公牛为XY型,母牛为XX型,29对常染色体为端着丝粒染色体,X染色体为近中着丝粒染色体,Y染色体为一较小的端着丝粒染色体,属于瘤牛型,BMY牛与婆罗门牛的核型差异不大,这与BMY牛的育种历史相符。BMY牛染色体与云南黄牛、牦牛、犏牛及尕里巴牛在数目和形态上大致相同,而与大额牛、云南野牛、马来半岛野牛、泰国野牛差异较大,相差1~2个罗伯逊易位。【结论】BMY牛染色体数为2n=60,与婆罗门牛核型无明显差异,Y染色体和婆罗门牛的Y染色体一样,为瘤牛型的端着丝粒染色体。

【Objective】 The research was to observe the karyotypes of BMY cattle and Brahman and to accumulate cytogenetic data for a new beef breed（BMY cattle）.【Method】 Metaphase chromosomes of BMY cattle and Braham were prepared from peripheral blood lymphocyte cultures.Conventional staining karyotypes of BMY cattle and Brahman were compared.【Result】 Both BMY cattle and Brahman have a diploid number of 2n=60 and the karyotypes consist of 29 pairs of acrocentric autosomes and one pair of sex chromosome.The sex（X） chromosomes in females are one pair of submetacentric chromosomes.The Y chromosome in males is a small acrocentric chromosome which is similar to indicus-type（or zebu-type）.There are no differences between the karyotypes from BMY cattle and Brahman,which is consistent with the breeding history of BMY cattle.BMY cattle＇s karyotypes are much the same to those of Yunnan yellow cattle,Yak,Penniu and Galiba ox in the chromosome numbers and patterns;but distinct differences exist in those of Mithum,Yunnan gaur;Malayan gaur and Thai gaur.【Conclusion】 The karyotypes of BMY cattle is 2n=60 with no apparent differences comparing to that of Brahman,and the Y chromosomes in BMY bulls are identical to Brahman＇s acrocentric Y chromosome belonging to indicus-type.