Worm Breeder's Gazette 8(2): 40
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.
In order to facilitate molecular analysis of the chromosomal domains in which the C. elegans yolk protein genes are situated, we have cloned the surrounding DNA using the chromosome walking technique. We have cloned at least 25 kb of DNA on each side of each yolk protein gene (> 230 kb total). Preliminary analysis of this DNA allows the following tentative conclusions to be drawn: 1. Walking, using J. Karn's SG25 (Sau3a partial digest) genomic library, has not presented us with any difficulties. All regions have been represented by overlapping clones. 2. The cloned DNA contains only four examples of middle repetitive DNA. The repeats appear to be small and to have a low copy number. They are not associated with detectable transcripts. 3. Seven regions transcribed in adult hermaphrodites, in addition to the five yolk protein genes, have been detected so far in the cloned DNA. The RNAs from all of these genes are present at levels less than 10% of the yolk protein mRNAs. (Very low abundance transcripts would not have been detected.) The walk has not yet been analyzed for the presence of genes transcribed in larvae or males. 4. Two Bristol/Bergerac polymorphisms have been found: A Tc1 between YP3 and YP4 allowed mapping of these genes to the X chromosome. A second 1.6 kb insertion about 30 kb to the right of YP1 has been detected in the Bergerac chromosome. 5. Except for the YP3 and YP4 genes, originally found on a single clone, the yolk protein genes are not clustered.