Cheng H H, Levin I, Vallejo R L, Khatib H, Dodgson J B, Crittenden L B, Hillel J
USDA, Agricultural Research Service, Avian Disease and Oncology Laboratory, East Lansing, Michigan 48823, USA.
Poult Sci. 1995 Nov;74(11):1855-74. doi: 10.3382/ps.0741855.
Microsatellites are tandem duplications with a simple motif of one to six bases as the repeat unit. Microsatellites provide an excellent opportunity for developing genetic markers of high utility because the number of repeats is highly polymorphic, and the assay to score microsatellite polymorphisms is quick and reliable because the procedure is based on the polymerase chain reaction (PCR). We have identified 404 microsatellite-containing clones of which 219 were suitable as microsatellite markers. Primers for 151 of these microsatellites were developed and used to detect polymorphisms in DNA samples extracted from the parents of two reference populations and three resource populations. Sixty, 39, 46, 49, and 61% of the microsatellites exhibited length polymorphisms in the East Lansing reference population, the Compton reference population, resource population No. 1 (developed to identify resistance genes to Marek's disease), resource population No. 2 (developed to identify genes involved in abdominal fat), and resource population No. 3 (developed to identify genes involved in production traits), respectively. The 91 microsatellites that were polymorphic in the East Lansing reference population were genotyped and 86 genetic markers were eventually mapped. In addition, 11 new random amplified polymorphic DNA (RAPD) markers and 24 new markers based on the chicken CR1 element were mapped. The addition of these markers increases the total number of markers on the East Lansing genetic map to 273, of which 243 markers are resolved into 32 linkage groups. The map coverage within linkage groups is 1,402 cM with an average spacing of 6.7 cM between loci. The utility of the genetic map is greatly enhanced by adding 86 microsatellite markers. Based on our current map, approximately 2,550 cM of the chicken genome is within 20 cM of at least one microsatellite marker.
微卫星是串联重复序列，其简单基序为1至6个碱基作为重复单元。微卫星为开发高实用性的遗传标记提供了绝佳机会，因为重复序列的数量具有高度多态性，而且由于该检测方法基于聚合酶链反应（PCR），所以用于对微卫星多态性进行评分的检测快速且可靠。我们鉴定出了404个含微卫星的克隆，其中219个适合作为微卫星标记。针对其中151个微卫星开发了引物，并用于检测从两个参考群体和三个资源群体的亲本中提取的DNA样本中的多态性。在东兰辛参考群体、康普顿参考群体、资源群体1（为鉴定马立克氏病抗性基因而培育）、资源群体2（为鉴定与腹部脂肪相关的基因而培育）和资源群体3（为鉴定与生产性状相关的基因而培育）中，分别有60%、39%、46%、49%和61%的微卫星表现出长度多态性。对在东兰辛参考群体中具有多态性的91个微卫星进行了基因分型，最终定位了86个遗传标记。此外，还定位了11个新的随机扩增多态性DNA（RAPD）标记和24个基于鸡CR1元件的新标记。这些标记的添加使东兰辛遗传图谱上的标记总数增加到273个，其中243个标记被归为32个连锁群。连锁群内的图谱覆盖范围为1402厘摩，基因座之间的平均间距为6.7厘摩。添加86个微卫星标记极大地增强了遗传图谱的实用性。根据我们目前的图谱，鸡基因组中约2550厘摩的区域距离至少一个微卫星标记在20厘摩以内。
