Worm Breeder's Gazette 13(2): 64 (February 1, 1994)
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 strain CB1517 is homozygous for the LG III fragments eDf2 and eDp6 and has a phenotype similar to unc-119 ( e2498 ),isolated as a spontaneous recessive Unc in an N2 /RW7000background (see WBG 11#4, p.82). Neither eDf2 nor eDp6 complement unc-119 mutations, suggesting that this gene is defective in CB1517 .Our approach toward analyzing the nature of the lesions of eDf2 and eDp6 is based on the hypothesis that the suspected common breakpoint of eDf2 and eDp6 lies within unc-119 .The "gap" is bridged by the YACs 39A1 (see Donna Albertson, Genetics 134: 211-219) and 60D9. By using pulsed-field gel electrophoresis and standard genomic Southerns, we were able to construct a long-range physical map of the region. The size of the overlap of the YACs 39A1 and 60D9 is about 100 kB.
Cosmid T27G1 ,which cross-hybridizes to 60D9 and 39A1, picks up a size polymorphism ( edP1 )associated with eDf2 ,which suggests that it contains the breakpoint. In order to obtain more clones in the region, we randomly subcloned Sst I fragments of PFG/LMP-purified 39A1 and 60D9. One of these clones, DP#MM008 ,contained DNA which cross-hybridizes only weakly to genomic DNA from CB1517 and which picks up a size polymorphism ( edP2 )associated with e2498 .A mut-6 ( st702 )-inducedphenotypic revertant of e2498 has lost this ~2.4 kB insertion, suggesting that the DP#MM008 clone falls between the breakpoints of eDf2 and eDp6 and contains at least part of unc-119 ,and that e2498 results from the insertion of a transposable element. Using this clone we constructed a short-range restriction map of the region around unc-119 and located the breakpoint of eDf2 and the insertion in e2498 to within 1 kB. We do not know the physical distance between DP#MM008 and T27G1 ,but it cannot be more than 100 kB, since T27G1 contains an end of 40C2. Since the breakpoint of eDf2 lies in DP#MM008 ,and T27G1 also picks up edP1 ,the end of eDf2 may be rearranged with respect to N2 .As well, eDp6 may be circular (see Hunter and Wood WBG 10#2 p.150).
