McRae Allan F, Beraldi Dario
Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, EH9 3JT, United Kingdom.
Mamm Genome. 2006 Apr;17(4):346-53. doi: 10.1007/s00335-005-0087-y. Epub 2006 Apr 4.
The availability of accurate linkage maps is an important step for the localization of genetic variants of interest. However, most studies in livestock assume the published map is applicable in their population despite the large differences between the breeds of a species. A region of sheep Chromosome 1 was previously identified as providing evidence for a marker order inconsistent with the published linkage map. In this study the identified region was investigated in more detail. Four microsatellite markers covering the central 5 cM of the inconsistent region and two flanking markers were genotyped in three sheep breeds, a commercial population (Charollais), an experimental population (Scottish Blackface), and a feral population (Soay). With the inclusion of the published linkage map, this provided evidence for three different marker orders across four sheep populations. Evidence for selection in this region was investigated using both a single-point allelic competition model and a multipoint allele-sharing statistic. Only the Charollais population provided evidence for selection, with significant transmission bias observed at marker BM7145. The implications of variation in linkage maps on the design and analysis of fine-mapping studies are discussed.
准确的连锁图谱对于定位感兴趣的遗传变异至关重要。然而，大多数家畜研究都假定已发表的图谱适用于其群体，尽管同一物种的不同品种之间存在很大差异。绵羊1号染色体的一个区域先前被确定为提供了与已发表连锁图谱不一致的标记顺序的证据。在本研究中，对确定的区域进行了更详细的调查。在三个绵羊品种中对覆盖不一致区域中央5厘摩的四个微卫星标记和两个侧翼标记进行了基因分型，这三个品种分别是一个商业群体（夏洛莱羊）、一个实验群体（苏格兰黑脸羊）和一个野生群体（索艾羊）。结合已发表的连锁图谱，这为四个绵羊群体中三种不同的标记顺序提供了证据。使用单点等位基因竞争模型和多点等位基因共享统计量对该区域的选择证据进行了研究。只有夏洛莱羊群体提供了选择证据，在标记BM7145处观察到显著的传递偏差。讨论了连锁图谱变异对精细定位研究的设计和分析的影响。
