Worm Breeder's Gazette 12(4): 21a (October 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.

The First Approach to Aligning the Genetic and Physical Maps on Chromosome I: Cosmid Rescue of Mapped Lethals

Thomas Hicks, Ann Rose

Department of Medical Genetics, University of British Columbia, Vancouver, B.C. V6 T13Z

For the left portion of chromosome I, where we have recovered lethals using sDp2 ,we are using cosmid rescue to align the genetic and physical maps. We also hope to obtain an estimate of the density of identified essential genes per cosmid. We have been using established transgenics (kindly sent to us by Heidi Browning and Janet Paulsen in Susan Strome's lab). As well we are constructing our own transgenics in order to have a representative collection of (frozen) genetic strains which carry cosmids or YACs for the majority of the sDp2 region (Thomas Hicks, Jennifer McDowall and Sheldon McKay, unpublished). The transgenics will be used as duplication strains and crossed to lethals to test for rescue. As a beginning, a set of lethals very close to dpy-5 are being tested. This set consists of fifty-five EMS-induced lethal mutations (from screens using sDp2 )that had been positioned within 0.5 map unit of dpy-5 .In order to subdivide this set, we have used the duplications hDp22 and hDp24 described by McKim and Rose (1990 Genetics 124:115). Lethal mutations within the intervals are being complementation tested to define essential genes. So far, one interval which contains three mutations has been completed and the genes, let-576 , let-577 and let-578 defined. Complementation testing for the other two intervals is not as yet complete, but one gene, let-575 ,has been identified which has at least three alleles. Lethals in the hDp24 to hDp22 interval are being crossed to strains constructed by Heidi Browning, which carry either the cosmid C24H1 or the YAC Y51G8 .The YAC rescues at least two of the lethals, h466 and h407 .The latter is also rescued by the cosmid C24H1 .

Literature Cited:

Thomas Hicks, Jennifer McDowall and Sheldon McKay, unpublished.

McKim and Rose, 1990 Genetics 124:115.