用RAPD技术筛选中国荷斯坦牛产奶量性状遗传标记

选用320条10碱基随机引物在由36头高产（305d产奶量〉8500kg）和32头低产（305d产奶量〈5600kg）中国荷斯坦牛所组成的2个DNA池间进行RAPD-PCR扩增，从中筛选出稳定性好、带型清晰且在2个DNA池间有明显差异的RAPD引物24条。用筛选到的24条引物对所有个体进行PCR检测，得到了5个与奶牛产奶量性状相关的RAPD标记，并对其中4个进行了克隆测序和SCAR标记转化以及生物信息学分析。结果表明：SCAR标记yield—s139与产奶量密切相关，应用电子克隆方法已将该标记由921bp延伸到2141bp，经同源性比较发现，此标记对应于奶牛基因组中LINEs家族中的一个重复元件，推测该元件附近可能存在与产奶量性状相关的QTLs或主效基因。

Screening of the Genetic Marker for the Milk Yield Trait in Chinese Holstein by RAPD Method

Two bovine genomic DNA pools were composed of 36 high-milk-yield Chinese Holstein cattles (milk yield in 305 days>8 500kg) and 32 low-milk yield Chinese Hostein cattles (milk yield<5 600kg). 24 high polymorphic RAPD primers selected from 320 arbitrary primers were used for analyzing genetic difference between two DNA pools. 5 specific fragments were obtained from DNAs of two groups cattles. 4 of them were sequenced and converted to SCAR markers. The results of statistic analysis showed that SCAR marker yield-S139 was highly associated with milk yield trait. By electronic cloning method the marker was extended from 921 bp to 2 141 bp. As a result, the fragment was a repeat element of LINE family in bovine genome by homologous analysis. So it was reasonably to assume that some QTLs or major genes associated with milk yield trait maybe lied in this LINE region.