Halbert Natalie D, Ward Todd J, Schnabel Robert D, Taylor Jeremy F, Derr James N
Department of Veterinary Pathobiology, College of Veterinary Medicine and Biochemical Sciences, Texas A&M University, College Station, TX 77843, USA.
Mol Ecol. 2005 Jul;14(8):2343-62. doi: 10.1111/j.1365-294x.2005.02591.x.
Introgressive hybridization is one of the major threats to species conservation, and is often induced by human influence on the natural habitat of wildlife species. The ability to accurately identify introgression is critical to understanding its importance in evolution and effective conservation management of species. Hybridization between North American bison (Bison bison) and domestic cattle (Bos taurus) as a result of human activities has been recorded for over 100 years, and domestic cattle mitochondrial DNA was previously detected in bison populations. In this study, linked microsatellite markers were used to identify domestic cattle chromosomal segments in 14 genomic regions from 14 bison populations. Cattle nuclear introgression was identified in five populations, with an average frequency per population ranging from 0.56% to 1.80%. This study represents the first use of linked molecular markers to examine introgression between mammalian species and the first demonstration of domestic cattle nuclear introgression in bison. To date, six public bison populations have been identified with no evidence of mitochondrial or nuclear domestic cattle introgression, providing information critical to the future management of bison genetic resources. The ability to identify even low levels of introgression resulting from historic hybridization events suggests that the use of linked molecular markers to identify introgression is a significant development in the study of introgressive hybridization across a broad range of taxa.
渐渗杂交是物种保护面临的主要威胁之一，通常是由人类对野生动物物种自然栖息地的影响所导致的。准确识别渐渗的能力对于理解其在物种进化和有效保护管理中的重要性至关重要。由于人类活动，北美野牛（Bison bison）和家牛（Bos taurus）之间的杂交已有100多年的记录，并且之前在家牛种群中检测到了家牛的线粒体DNA。在本研究中，使用连锁微卫星标记来识别来自14个野牛种群的14个基因组区域中的家牛染色体片段。在五个种群中鉴定出了家牛的核基因渐渗，每个种群的平均频率在0.56%至1.80%之间。本研究首次使用连锁分子标记来研究哺乳动物物种之间的渐渗，也是首次证明家牛核基因在家牛中的渐渗。迄今为止，已确定有六个公共野牛种群没有线粒体或家牛核基因渐渗的证据，这为野牛遗传资源的未来管理提供了关键信息。能够识别历史杂交事件导致的低水平渐渗表明，使用连锁分子标记来识别渐渗是跨广泛分类群的渐渗杂交研究中的一项重大进展。
