Bubb K L, Bovee D, Buckley D, Haugen E, Kibukawa M, Paddock M, Palmieri A, Subramanian S, Zhou Y, Kaul R, Green P, Olson M V
Department of Genome Sciences, University of Washington Genome Center, Seattle, Washington 98195, USA.
Genetics. 2006 Aug;173(4):2165-77. doi: 10.1534/genetics.106.055715. Epub 2006 Jun 4.
There has been much speculation as to what role balancing selection has played in evolution. In an attempt to identify regions, such as HLA, at which polymorphism has been maintained in the human population for millions of years, we scanned the human genome for regions of high SNP density. We found 16 regions that, outside of HLA and ABO, are the most highly polymorphic regions yet described; however, evidence for balancing selection at these sites is notably lacking--indeed, whole-genome simulations indicate that our findings are expected under neutrality. We propose that (i) because it is rarely stable, long-term balancing selection is an evolutionary oddity, and (ii) when a balanced polymorphism is ancient in origin, the requirements for detection by means of SNP data alone will rarely be met.
关于平衡选择在进化中所起的作用，已经有很多猜测。为了识别像人类白细胞抗原（HLA）这样在人类群体中多态性维持了数百万年的区域，我们扫描了人类基因组以寻找单核苷酸多态性（SNP）密度高的区域。我们发现了16个区域，这些区域在HLA和ABO之外，是迄今所描述的多态性最高的区域；然而，在这些位点存在平衡选择的证据明显不足——实际上，全基因组模拟表明我们的发现符合中性预期。我们提出：（i）由于长期平衡选择很少稳定，所以它是一种进化上的奇特现象；（ii）当平衡多态性起源古老时，仅通过SNP数据进行检测的要求很少能得到满足。
