We previously reported the identification of two alleles ofgon-2 ,
q362 andq388 .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 thanq362 .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 fromunc-29 (
e1O72)
lin-11 (
n566)/gon-2 (
q388)had sterileF1 progeny. Reassuringly, all of the Lin-non-Uncs produced GonF2 s.Therefore, we concluded thatgon-2 is near or to the left ofunc-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 ofgon-2 (
q388).To distinguish between these possibilities, we constructedgon-2 (
q388Jlin-11 (
n566)/++ and kept subcloning animals until we found
agon-2 (
q388)/gon-2 (
q388)
lin-11 recombinant. We used this strain to constructgon-2 (
q388)/+. Through a combination of selfing and replica-plating, we found that the zygotic effect sterility ofgon-2 (388)was restored by the removal oflin-11 (
n566).We are currently testinglin-11 (
n389)to see if it can also suppress the sterility caused bygon-2 (388). We also testedgon-2 (
q388)over a set of deficiencies. Hermaphrodites of genotypenDf23 /q388 ,nDf24 /q388 andnDf25 /q388 were raised at 20 (permissive temperature) then shifted to 25 to lay eggs. In each case, theF1 progeny had a Gon phenotype. These results narrowed down the location of thegon-2 gene to a relatively small region. Finally, we did three factor mapping withdpy-5 (
e61)
unc29 (
e1 O72 )/
q388 .10/12 Dpy-non-Unc and 5/19 Unc-non-Dpy recombinants picked upgon-2 (
q388).Combining all these mapping data together, we conclude thatgon-2 is to the left ofunc-29 ,nearfer-1 .We are constructingdpy-5fer-1unc-29 /q388 for use in determining whethergon-2 is to the left or right offer-1 Any day now we will attempt to get transformation rescue by microinjecting candidate YACs and cosmids from the region.