Submitted to: Euphytica
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/10/2004
Publication Date: 6/1/2005
Citation: Wu, J., Zhu, J., Jenkins, J.N., McCarty Jr., J.C. 2005. Constructing linkage maps with achiasmatic gametogenesis. Acta Genetica Sinica. 32:608-615. Interpretive Summary: Conventional genetic linkage methods are based upon the assumption that chromosome crossing-over occurs in both males and females. This is not true for some insects where crossing-over occurs in only one of the sexes. We describe a new method for calculating linkage of sex and non-sex linked genes in organisms which have crossing-over in only one sex. We compared the new method with conventional methods by simulation and showed that the new method provided unbiased estimations, while the conventional method gave underestimated linkage values. The powers for grouping into linkage groups and for ordering genes within a linkage group were superior using the new method. Software for calculations using the new method is available from the authors.
Technical Abstract: Conventional linkage methods were based on the assumptions of the occurrence of the chiasmata in both male and female gametogenesis. In this study, a new method was proposed and the corresponding software package was developed for constructing sex and non-sex linkage maps for organisms having achiasmata during gametogenesis. The detection of sex-linked markers is efficient by a chi-square test. The estimation of recombination frequency and mapping powers were compared between the conventional method and the new proposed method by Monte Carlo simulations. Simulation results showed that the new proposed method provided unbiased estimations, while the conventional method gave underestimated distances. The powers of grouping and ordering obtained at significant level of 0.05 by the new proposed method were significantly greater than those by the conventional method for most cases. Therefore, the new method could be used to obtain desirable linkage map powers in organisms like silkworm (Bombyx mori L.).