Institute of Genetics, Vetsuisse Faculty, University of Berne, Berne, Switzerland.
Anim Genet. 2010 Jun;41(3):304-7. doi: 10.1111/j.1365-2052.2009.01987.x. Epub 2009 Nov 16.
We recently mapped the belt mutation in Brown Swiss cattle to a 922 kb interval on BTA3. In this study, we analysed two additional cattle breeds with the belted phenotype: Galloway and Dutch Belted (Lakenvelder). By genotyping microsatellites in solid-coloured and belted Galloways, we confirmed that the belt mutation in Galloways is strongly associated with the same chromosomal locus as in Brown Swiss cattle. Subsequently, we analysed 36 SNPs in the belt interval in three breeds. We identified a single belt-associated haplotype for each of the analysed breeds. The three breed-specific belt haplotypes share alleles in four blocks. Three of these blocks comprise only one single or two consecutive markers, while the largest shared haplotype block encompasses nine consecutive SNPs in a 336 kb interval. The large shared haplotype across divergent breeds suggests a common mutation for the belt phenotype in all three breeds. We identified a potential candidate gene within this interval coding for the developmental transcription factor HES6. We re-sequenced the complete HES6 coding sequence in belted and solid-coloured cattle but did not find belt-associated polymorphisms. In conclusion, our data provide strong evidence in favour of a common founder for the belt phenotype in different cattle breeds and have resulted in an improved fine-mapping of the causative mutation.
我们最近将瑞士褐牛的带纹突变映射到 BTA3 上的 922 kb 区间。在这项研究中，我们分析了另外两个具有带纹表型的牛种：盖洛威牛和荷兰牛（拉肯弗尔德牛）。通过对纯色和带纹盖洛威牛的微卫星进行基因分型，我们证实了盖洛威牛的带纹突变与瑞士褐牛的同一染色体位点密切相关。随后，我们在三个品种中分析了带纹区间的 36 个 SNP。我们为每个分析的品种确定了一个单一的带相关单倍型。三个品种特异性的带单倍型在四个块中共享等位基因。这三个块中的三个仅包含一个或两个连续的标记，而最大的共享单倍型块包含 336 kb 区间中的九个连续 SNP。不同品种之间的大型共享单倍型表明，所有三个品种的带纹表型都有一个共同的突变。我们在这个区间内鉴定出一个编码发育转录因子 HES6 的潜在候选基因。我们在带纹和纯色牛中重新测序了完整的 HES6 编码序列，但没有发现与带纹相关的多态性。总之，我们的数据为不同牛种的带纹表型存在共同的起源提供了有力的证据，并导致了对致病突变的精细定位得到了改善。
