中国黄牛Y染色体多态性及品种起源演变的探讨

 用G带、C带、RBA带、常规和C带或RBA带连续染色技术研究了中国9个地方黄牛品种的66头人工授精用公牛、41头小公牛和12头母牛的染色体，着重研究了它们Y染色体的多态性。北方的蒙古牛和延边牛是无肩峰牛，具有普通牛核型，其Y染色体分别为亚中和中着丝点。中原地区的秦川牛、晋南牛在每个品种中均发现了亚中、中和近端着丝点Y染色体，而郏县红牛中存在着中和近端着丝点两种形态Y染色体、这几个品种应是由肩峰牛和无肩峰牛长期融合形成的。西镇牛、鲁西牛、南阳牛、温岭高峰牛均具有瘤牛类型的Y染色体，是以瘤牛为基础形成的品种。经RBA带鉴别，西镇牛Y染色体无短臂，为端着丝点染色体，其余3个品种为近端着丝点Y染色体。结合国内有关黄牛染色体研究材料，讨论了中国黄牛的分类和起源。认为中国的无肩峰黄牛除来源于具亚中着丝点Y染色体的蒙古牛之外，还应来源于另一种分布范围很广的，具中着丝点Y染色体的无肩峰牛。鉴于现有的肩峰黄牛品种中Y染色体形态和带型差异，可能古代生存于中国的瘤牛已发生分化。中国黄牛诸品种应由不同类型的无峰牛和肩峰牛经长期选育和杂交而形成的。

CHROMOSOME STUDY ON SOME LOCAL BREEDS OF CHINESE YELLOW CATTLE

The chromosomes, especially Y chromosome polymorphism of nine local breeds of Chinese yellow cattle, which included 66 AI bulls, 41 young bulls and 12 cows, were studied with G-, C-, RBA-banding and sequential routine and C-or RBA-banding technique. The submetacentric and metacentric Y chromosomes of humpless Taurus cattle were respectively found in Mongolia and Yunbian cattle in northern China. Three types of Y chromosomes, metacentric, submetacentric and acrocentric, were found in each breed of Qinchuan and Jinnan in central China, but there were two morphologies of Y chromosomes which were metacentric and acrocentric in Jiaxian red cattle in the same region. The Y chromosomes of Xizhen, Luxi, Nanyang and Wenling humped cattle were similar to that of humped Zehe cattle. Having been identified with RBA-Banding technique, Y chromosome of Xizhen showed no short arm, so it belonged to telueentric chromosome, but other three breeds had acrocentric Y chromosomes. In addition, there was a difference in RBA-banding pattern of Ychromosomes between Luxi and Wenling humped cattle.Based on the present paper and other papers conceroing cytogenetical research of yellow cattle, the classification and origin of Chinese yellow cattle was discussed. In the hmnpless cattle, besides submetacentric Y chromosomes in Mongolia , there are still metacentric Y chromosomes destributing in many breeds, even in Lijian cattle in southwestern China, so apart from Bos taurus mongolicus, it is possible that there was another ancestor of humpless yellow cattle which possessed metacentric Y chromosomes and ever existed extensively in ancient China Because there are differences from the morphology and banding pattern of Y chromosomes in the present hmnped cattle breeds, it is possible that the differentiation already occured in the wild ancestors of zebu living in ancient China. All breeds of Chinese yellow cattle should be produced for a long period which was crossed and bred from the different types of humped and humpless cattle.