Worm Breeder's Gazette 12(2): 99 (January 1, 1992)
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
As has been reported earlier (C. elegans meeting abstracts, 1991) him-8 asymmetrically affects recombination on the X chromosome; i.e., recombination is elevated above wild type (150%) near unc-1 and decreases to 3% of wild type near lin-15 .We have followed up this result by examining the effects of him-5 and him-1 on recombination over different intervals. Plotted below are the results relative to the wild type amount of recombination seen for each interval. Strikingly, both him-5 and him-1 have the same qualitative effect on X chromosome recombination as him-8 ,but with quantitative differences. The greatest difference is with him-1 ,where wild type levels of recombination occur over a larger amount of chromosome. This could account for the less severe non-disjunction phenotype (amount of males) seen with him-1 .We hypothesize that the him-8 , him-5 and him-1 gene products are components of an X chromosome pairing system that are asymmetrically distributed or utilized along the length of the chromosome. Molecular analysis of these genes should further elucidate their function.
[See Figure 1]
We have rescued the non-disjunction phenotype of him-8 by cosmid injection using rol-6 selection for transformants. Injection of both cosmids T19G9 and ZK188 severely decreases the number of male progeny produced by a him-8 ( e1489 ); mab-23 strain (kindly provided by Jonathan Hodgkin). Injection of the neighboring cosmid C47C9 has no effect on the number of males produced. The region of cosmid overlap has been used to isolate corresponding phage clones. These are currently being screened and tested for rescue.