Worm Breeder's Gazette 10(3): 91
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.
To identify genes necessary for normal male tail development we are screening for mutants defective in male tail morphology or mating behavior using the screen developed by J. Hodgkin [Genetics 103:43-64 (1983)]. From examination of the males produced by 834 independent F2 clones derived from mutagenized him-5(e1490) grandparents, we have obtained 27 mutant strains with abnormal male tail morphology (Mab). ( An additional 15 strains have abnormal males, but also have hermaphrodite defects such as uncoordinated movement or dumpy body shape and thus are probably alleles of known genes). We have examined the gross anatomy of males of these strains and found that six mutants have tail defects reflecting abnormalities in epidermal development; sixteen have defects primarily in the proctodeum; and five have defects in gonadogenesis such that the gonad does not connect to the proctodeum. We are particularly interested in mutants with defects in spicule formation (M & B lineages) or gonadogenesis (Z1 & Z4 lineages). A second class of mutants obtained in this screen are anatomically normal yet defective in copulation (we call these Cod for 'copulation defective'). Each of the four Cod mutants mate with <1% of wild-type efficiency. Because a major class of mutants defective in a variety of behaviors including male mating fail to avoid high osmotic strength media, we tested the Cod mutants for this behavior using J. Thomas' assay [WBG10(1)89-90]. All mutants displayed wild-type behavior as compared to him-5 and osm-3; , indicating that we have not just reisolated alleles of known genes. To better characterize these Cod mutants, we have started to develop assays for various steps in copulation. We have developed an assay for the attraction of males to hermaphrodites based on the original observations of J. Sulston and R. Horvitz. In this assay, paralyzed hermaphrodites [unc-52(e444)] are placed in the center of a dry 5cm plate with full bacterial lawn ( The dryness of the plate is crucial) and allowed to incubate for six hours. Following this time, a male is placed on the edge of the plate. Examination of the tracks made on the lawn indicates whether tracking occurred. In a typical assay, 10/12 him-5(e1490) males reach the hermaphrodites within 25 minutes. Once a male reaches the hermaphrodites, it stays nearby (Jim Thomas' 'accumulation'). Both of the Cod mutants tested, sy38 and sy48, were essentially wildtype for this behavior,with 20/36 and 24/36 males tracking, respectively. In these experiments, N2 hermaphrodites served as a negative control, with 0/10 hermaphrodites tracking successfully. Some mutants first identified on the basis of mating defects, on closer examination, turned out to have anatomical defects; these have been included in the Mab category. For example, sy56 III, which has a male-specific defect in germ line proliferation, was picked up as a Cod mutant. This observation indicates the efficacy of the behavioral screen, as we would have missed such subtle anatomical defects looking only at low magnification.