Worm Breeder's Gazette 11(1): 23
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.
The region of chromosome I, defined by the breakpoints of hDp19 (K. McKim, personal communication) and sDp2 (Rose et al, 1984), contains the dpy-14 gene, other visibles and at least nineteen essential genes. Two other duplication breakpoints, hDp58 and hDp62 (K. McKim, personal communication), are located in this region and are being used to position the genes. The dpy-14 region is located within a large contig on linkage group I (A. Coulson and J. Sulston, personal communication). Within a portion of this region ten coding regions have been identified in 170 kb. of DNA flanking the polymorphisms sP1 and hP9 (Starr et al., 1989) . The N2/B0 polymorphic fragment sP1, which is included in the cosmid T21G5 has been positioned very close to dpy-14 by Starr et al.(1989). However, the dpy-14 gene had not been recombinationally separated from sP1. We have used the cosmids T13C1, T14D10 and T21G5 mixed together to rescue the Dpy-14 phenotype. Rescue was achieved by microinjecting the cosmid DNAs into the mature oocytes of 'wild type' nematodes with the genotype dpy-5 y-5 p2. One Dpy-5 animal indicative of dpy-14 rescue was identified in the F1 progeny. In the F2 both Dpy-5 and Dpy-5 were scored which indicated the cosmid rescue to be extrachromosomal (hEx1). A similar attempt with the individual cosmid T13C1, which contains a coding region homologous to col-4 (T. Starr, personal communication), did not rescue the Dpy-14 phenotype. When the cosmid T14D10 was used extrachromosomal rescue of the Dpy-14 phenotype was obtained (hEx2). Since this cosmid does not have any homology to the collagen genes, dpy-14 gene is not likely to be a collagen. The observation that the dpy-14 gene lies in the cosmid T14D10 has positioned the sP1 polymorphic site to the right of dpy-14. Four of the identified ten coding regions lie in the cosmid T14D10, one of which encodes the snRNA U1-1 (T. Blumenthal, personal communication; T. Starr, personal communication). An attempt to rescue the Dpy-14 phenotype with another coding region was negative. Therefore, we believe that one of two coding regions in T14D10 is the dpy-14 gene. Attempts are underway to determine which of these coding regions contains the dpy- 14 gene. This work was supported by the grant from Medical Research Council of Canada to AR.