Tan Y D
College of Life Science, Hunan Normal University, Changsha 410081, China.
Yi Chuan Xue Bao. 2001;28(1):83-94.
The method for constructing linkage maps has almost been so far the three-point testcross in higher organisms. This method is, however, considerably limited to a requirement of a parent or line with three recessive genes that can be obtained by only cross breeding. In this paper, the three-point selfcross method for mapping was proposed. This method can also provide us with informations of mapping as the same as the three-point testcross method. However, the three-point selfcross method does not have any limitation of requiring a parent with three recessive genes. It was theoretically proved that this method could be used to map molecular marker loci in small sample of F2 population. Exactly to test both the methods for mapping, Fisher information content was applied to prove that the three-point selfcross method is powerful for mapping. Further to test this method, data of the first 6 loci were chosen from 12 RFLP loci detected in 333 F2 individuals in SAMPLE. RAW file in MAPMAKER/EXP version 3.0 that Lander et al. (1987) provided. The result showed that, like MAPMAKER program, the three-point selfcross method is powerful to detect linkage relationship among loci, to order them on linkage groups and to calculate distances between nearest neighbor loci. Besides, this method could provide us with the other information of map such as the positive or negative interference and couple or repulsion configuration.
到目前为止，在高等生物中构建连锁图谱的方法几乎一直是三点测交法。然而，这种方法在很大程度上受到限制，需要一个具有三个隐性基因的亲本或品系，而这只能通过杂交育种获得。本文提出了三点自交法用于图谱构建。这种方法也能像三点测交法一样为我们提供图谱信息。然而，三点自交法不存在需要具有三个隐性基因的亲本的限制。从理论上证明了该方法可用于在F2群体的小样本中对分子标记位点进行图谱构建。为了确切地测试这两种图谱构建方法，应用费希尔信息含量来证明三点自交法在图谱构建方面的有效性。为了进一步测试该方法，从SAMPLE中333个F2个体检测到的12个RFLP位点中选取了前6个位点的数据。这些数据来自兰德等人（1987年）提供的MAPMAKER/EXP 3.0版本的RAW文件。结果表明，与MAPMAKER程序一样，三点自交法在检测位点间的连锁关系、在连锁群上对它们进行排序以及计算相邻最近位点之间的距离方面很有效。此外，这种方法还能为我们提供图谱的其他信息，如正干扰或负干扰以及相引或相斥构型。
