Worm Breeder's Gazette 11(2): 86
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.
Recent observations have led us to believe that there may be as yet unidentified essential genes residing in the dpy-20-unc-22 interval. First, the entire sDf2 region is estimated to be 70% saturated for mutations in essential genes (D. V. Clark, Ph.D. thesis). Second, interspecies cross hybridization has been used to identify eight coding elements located on four cosmids that cover about two-thirds of the dpy-20-unc-22 region (Prasad and Baillie,1989). Extrapolation of this data yields an estimate of approximately 12 genes between dpy-20 and unc-22. To date, four genes between dpy-20 and unc-22 have been identified. Three of these four are essential genes having zygotic lethal mutant phenotypes. These include let-92 (2 alleles), let-653 ( 1 allele), and let-56 (8 alleles). In addition, par-5 also maps to this region (D. Shakes, pers. comm.). We are currently analyzing 11 EMS-induced lethal mutations that fail to complement sDf2, efore map within the dpy-20-unc- 22 region. This set of 11 lethal alleles doubles the existing sample size of 11 lethal alleles within the interval, and may well define previously unidentified genes. Such a finding would be supported by Prasad's result. As we are interested in the nature and organization of all genes within the dpy-20-unc-22 interval, we would appreciate hearing from those having any new information on genes within or near this region. [See Figure 1]