构建分子标记连锁图谱的一种新方法：三点自交法

作者从数学上导出了基因作图的三点自交方法。这一方法同用三点测交法一样能提供各种作图信息，但不需要选育三隐性纯合基因亲本或品系，因而能大大提高作图功效。，从理论上证明，该方法也适合于小群体作图分子标记连锁图谱，同时用Ｆisher单一观察信息（即Ｆ信息）量证明，三点自交法是一种有效的作图方法，应用ＭＡＰＭＡＫＥＲ程序中所提供的才鼠Ｆ２群体中３３３个个体的１２个ＲＦＬＰ标记位点中前６个位点的数据对三点自交图图距计算具有与ＭＡＰＭＡＫＥＲ程序一样的功能，而且还提供了位点间的交叉干涉和位点的相引或相斥构型等信息以及紧密位点间发生负干涉作用的证据。

A New Method for Constructing Linkage Maps of Molecular Markers: Three-Point Selfcross Method

The method for constructing linkage maps has almost been so farthe 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杙oint testcross method. However, the three杙oint 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.