Worm Breeder's Gazette 7(1): 51
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.
C. elegans var. Bergerac worms contain 1.7 kb of DNA adjacent to actin gene III that var. Bristol worms do not. This DNA polymorphism has been used as a phenotypic marker for mapping the cluster of actin genes I, II and III. We were interested to know more about this 1.7 kb of DNA. Other polymorphisms that were also 1.7 kb larger in Bergerac appeared after hybridization to randomly cloned fragments of Bristol DNA (Emmons et al., PNAS 76, 1333 (1979)). A DNA fragment containing the 1.7 kb insert was cloned from a lambda Charon-10 Bergerac recombinant DNA library. This clone hybridized strongly to about 50 bands in a whole genome blot of Bergerac DNA. The clone hybridized less strongly to Bristol DNA and hybridization was to a different set of about 30 bands. Subfragments of the cloned Bergerac DNA were used as hybridization probes against each other and revealed that the 1.7 kb insert is terminally repetitious. The end subfragments did not hybridize to the middle subfragment. The end and middle subfragments gave the same patterns when hybridized to whole genome blots of Bergerac and Bristol DNA's. The cloned Bergerac DNA was denatured, quick-cooled and examined in the EM and it revealed a single-strand 1.5 kb loop with a double-strand stem of about 75 bp. Therefore, the terminally repetitious ends contain inverted sequences. We hybridized the 1.7 kb DNA to blots of DNAs from worms from the Hirsh, Ward, Riddle labs and from the stock center. All had the same patterns. Two different patterns were found after hybridization to the wild strains PA-1 and C12A (from Carl Johnson) but no differences were seen with GA-l (from Carl Johnson's backyard). We don't know if this is a transposon but it seems like one. We also don't know if it's transcribed.