晋南黄牛的染色体分析

以晋南黄牛为实验材料,做了染色体的常规分析。测量了各号染色体的相对长度、着丝点指数及臂比,并做了染色体的C带、R带及银染核仁组织者区(Ag-NORs)的分析。染色体常规染色及C带、R带分析表明:晋南黄牛公牛的核型为2n=60,XY。Y染色体有两种形态,一为近端着丝点染色体,另一为中着丝点染色体。Ag-NORs定位于第2、8、4、11、21(或22)及28号常染色体的末端,银染频率为每细胞6.109。讨论了另一品种双核型现象。认为晋南黄牛是我国北方普通牛与南方肩峰牛两大牛群汇合的交汇点之一。     

秦川牛的染色体研究

对秦川牛(12♂,3♀)染色体的核型、G带、C带及Ag-NOR_s的研究表明:秦川牛品种内Y染色体存在多态现象,Y染色体有中、亚中和近端着丝点染色体。中和亚中着丝点Y染色体G带和C带与普通牛(Bos taurus)相同,近端着丝点Y染色体G带和C带与瘤牛(Bos indicus)相同。根据Y染色体多态性,讨论了秦川牛起源的多元性。统计了2002个细胞的Ag-NOR_s数目,每细胞Ag-NOR_s数变化范围3～10个,平均5.473±0.316。     

C- AND G- BANDING PATTERNS AND CHROMOSOMAL MORPHOLOGY OF SOME BREEDS OF AUSTRALIAN CATTLE

A cytogenetical study using metaphase chromosomes from cultured lymphocytes, was made of 2 Banteng (Bibos banteng) steers and 218 bulls representing 13 purebreeds (Bos taurus type, Bos indicus type and Sanga) and 7 cross-breeds. Studies were made of photographic karyotypes of Giemsa stained and C-banded chromosomes of bulls of each breed and of B-banded chromosomes from 3 breeds of Bos indicus and one cross-breed Australian Friesian Sahiwal) cattle. The relative lengths of chromosomes of Bos taurus and Bos indicus bulls were compared and significant difference in relative lengths of the X chromosomes were noted between these two species. There was a differences in morphology of the Y chromosomes; Sanga, Banteng and Bos taurus type breeds had a small submetacentric Y chromosome, except for the Jersey which had a metacentric Y chromosome. All Bos indicus type bulls had an acrocentric Y chromosome but the Droughtmaster breed had two forms of the Y chromosome (submetacentric and acrocentric). The C-banding patterns of the autosomes and X chromosomes were similar for all breeds while those of the Y chromosomes of Bos indicus type cattle allowed their accurate identification. G-banding patterns of Bos indicus resembled those of Bos taurus and enabled pairing of homologous chromosomes. Centromeres of the autosomes were unstained but those of the sex chromosomes were darkly stained.     

秦川牛Y染色体多态性与精液品质,体尺及外貌特征关系的探讨

在秦川牛品种中，Ｙ染色体具有多态性，即中或亚中及近端着丝点Ｙ染色体。对不同类型Ｙ染色体公牛的精液品质，体尺及外貌特征进行了统计分析。结果表明，Ｙ染色体多态性与精液品质，体尺及外貌特征不存在一定的相关关系。并对其意义和原因进行了讨论。