Submitted to: Animal Biotechnology International Workshop Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 11, 1997
Publication Date: N/A
Interpretive Summary: Random amplified polymorphic DNA (RAPD) can be a useful tool in gene mapping studies because several RAPD markers can be genotyped at a cost similar to that for genotyping a microsatellite marker. However, RAPD markers generally exhibit dominant inheritance mode, and several theoretical and methodology issues have been unresolved for construction of genetic linkage maps using dominant markers. This study provided polymorphism and linkage information measures, analyzed design issues of reference families for dominant markers, and provided a method to analyze a large number of dominant markers simultaneously and to integrate linkage maps of dominant markers with those of codominant markers. These information measures and methods will allow scientists to make better use of dominant genetic markers when designing gene mapping research.
Polymorphic and linkage information contents were derived for dominant markers. Polymorphic information content (PIC) for a dominant marker is at most 75% of that for a codominant marker assuming equal allele frequencies. Linkage information content (LIC) of dominant markers is much lower than that for codominant markers, because LIC considers two markers jointly. Because of low PIC and LIC, two strategies were proposed for mapping of dominant markers: large families and small detection level of recombination frequency. Large families are necessary because the parental linkage phase can be determined using two-generation data instead of three-generation data, for which dominant markers have extremely low LIC. Small detection level is desirable because the sample size of the reference families can be at a more practical level. A method to apply computer packages for codominant markers to linkage analysis for dominant markers was proposed for simultaneous analysis of a large number of dominant markers and for integration of linkage maps of dominant and codominant markers.