Worm Breeder's Gazette 8(3): 29

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.

More Sterile Mutants

J. Kimble

5000 F1 clones have been screened for mutants causing defects in 
either the lineage of the somatic gonad or specific postembryonic germ 
line controls.  Both classes have been identified.  All mutations lead 
to a recessive sterile phenotype.  Work on mutants affecting the 
somatic lineage is very preliminary, and therefore will be described 
in a later issue.  Mutants affecting postembryonic germ line 
development fall into three phenotypic classes.  These include 5 
mutants (at least 3 genes) with a Fem phenotype (oocytes only in the 
hermaphrodite germ line), 5 mutants (at least 3 genes) with a Mgl 
phenotype (masculinization of the germ line), and 5 mutants (at least 
2 genes) with a Glp phenotype (germ line proliferation defective).  
Mutants with a Mgl phenotype have a sexually transformed germ line 
leading to continuous sperm production into the distal arm of the 
hermaphrodite gonad.
Most is known about the Glp mutants.  The mutant phenotype of glp-1 
is similar to the laser phenotype of animals in which the distal tip 
cell was ablated during L1.  Z2 and Z3 divide a couple of times, and 
all their descendants enter meiosis and differentiate as sperm.  The 
hermaphrodite and male germ line is affected equally.  The distal tip 
cells, however, are present, and their role as leader cell in the 
hermaphrodite gonad is unaffected.  The hermaphrodite somatic gonad 
thus possesses two U-shaped arms made of somatic epithelial or sheath 
cells and a small number of sperm scattered throughout the arm.  No 
affect on the somatic structures of the gonad of either sex has been 
seen.  The three alleles of glp-1 have this same gonadal phenotype 
leading to sterility.  None are temperature sensitive.  The map 
position is .1% to the right of unc-32.  Its position with respect to 
lin-12 has not yet been determined.  Two Glp alleles that do not map 
to glp-1 have a somewhat different phenotype.  Z2 and Z3 divide only a 
couple of times, but no differentiation ensues.  The distal tip cell 
is enlarged and vacuolated.  The map position of these other alleles 
is not yet known.