Worm Breeder's Gazette 13(2): 46 (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.
We previously reported the identification of two alleles of gon-2 , q362 and q388 .Each mutation causes a partial maternal effect Gon (gonadless) phenotype; either maternal or zygotic expression is sufficient to rescue the Gon phenotype. The amount of gonad development is variably penetrant for both alleles. However, in severely affected individuals, the four gonad progenitors fail to undergo any divisions.
q388 is temperature sensitive and has a more penetrant Gon phenotype than q362 .At the restrictive temperature, q388 also causes recessive zygotic effect sterility. We have not yet determined the basis for this sterility, but both oocytes and sperm are made.
During the course of three factor mapping experiments, we encountered an unexpected result: None of the Lin-non-Unc or Unc-nonLin recombinants that we picked from unc-29 ( e1 O72) lin-11 ( n566 )/ gon-2 ( q388 )had sterile F1 progeny. Reassuringly, all of the Lin-non-Uncs produced Gon F2 s.Therefore, we concluded that gon-2 is near or to the left of unc-29 .We also reasoned that either a) we had recombined away some linked mutation responsible for zygotic sterility or b) lin-1 ( n566 )suppresses the zygotic effect sterility of gon-2 ( q388 ).To distinguish between these possibilities, we constructed gon-2 ( q388 J lin-11 ( n566 )/++ and kept subcloning animals until we found a gon-2 ( q388 )/ gon-2 ( q388 ) lin-11 recombinant. We used this strain to construct gon-2 ( q388 )/+. Through a combination of selfing and replica-plating, we found that the zygotic effect sterility of gon-2 (388)was restored by the removal of lin-11 ( n566 ).We are currently testing lin-11 ( n389 )to see if it can also suppress the sterility caused by gon-2 (388).
We also tested gon-2 ( q388 )over a set of deficiencies. Hermaphrodites of genotype nDf23 / q388 , nDf24 / q388 and nDf25 / q388 were raised at 20° (permissive temperature) then shifted to 25° to lay eggs. In each case, the F1 progeny had a Gon phenotype. These results narrowed down the location of the gon-2 gene to a relatively small region.
Finally, we did three factor mapping with dpy-5 ( e61 ) unc29 ( e1 O72 )/ q388 .10/12 Dpy-non-Unc and 5/19 Unc-non-Dpy recombinants picked up gon-2 ( q388 ).Combining all these mapping data together, we conclude that gon-2 is to the left of unc-29 ,near fer-1 .We are constructing dpy-5 fer-1 unc-29 / q388 for use in determining whether gon-2 is to the left or right of fer-1
Any day now we will attempt to get transformation rescue by microinjecting candidate YACs and cosmids from the region.