To test this hypothesis, the Maine researchers closed in on a region of the t haplotype known to be involved in these phenomena. They used this information to develop transgenic mice that carried the candidate region derived from the wild haplotype.
When the transgenic region segregated with the t haplotype, the researchers noted that males carrying two copies of the t haplotype plus the transgenic region were fertile and showed no transmission ratio distortion. Therefore, the scientists realized, two genes must be involved-one controlling sterility and a yet-to-be discovered gene regulating transmission ratio distortion.
Dr. Planchart commented, "For more than 50 years, researchers have sought the biochemical and molecular basis of these phenomena. This work represents a landmark study of the genetics of the t haplotype-it shows for the first time that different genes within the haplotype cause transmission ratio distortion and sterility."
The research is published in the March 1 issue of the Proceedings of the National Academy of Sciences.