Worm Breeder's Gazette 4(1): 19

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 on Roller Mutants

J. Cox, B. Edgar

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Figure 3

We have now completed a study of some 90 roller mutants.  The 
accompanying table indicates the genes which can mutate to give a 
roller phenotype.  Several new genes have been identified and several 
mapping errors were found.  e187, a widely used roller allele of dpy-2,
is the canonical allele of another closely linked gene rol-6.  The E8 
E26 strain usually used for complementation testing at the dpy-2 locus 
is in fact a triple mutant containing a non-visible allele of the rol-
6 gene, which is where the confusion among these mutants arose.  unc-
76 is closer to the cluster on chromosome V than previously indicated. 
It is within 0.3 map units of rol-4, which is located 2.9 + .8 map 
units to the right of unc-42.  The new position of unc-76 was checked 
by mapping against dpy-11.We have found that the genes fall into five 
different classes with regard to phenotypic characteristics: left 
roller (LR), right roller (RR), left squat (LS), right squat (RS), and 
left dumpy roller (LDR).  Mutants of genes in these groups show 
remarkably distinctive phenotypic differences in terms of roller 
handedness, time of onset of phenotype, presence or absence of a dumpy 
phenotype, and effects on cuticle morphology.  All roller alleles of 
these genes possess a helically twisted cuticle.  Some genes contain 
nonroller alleles and the cuticles of these mutants are found to be 
straight.  Other types of cuticle aberrations are listed in the table. 
The most bizarre phenotypes are manifest by the squats which are 
rollers as heterozygotes but straight non-rollers as homozygotes.  The 
right squat homozygotes roll only during the L3 and dauer stages and 
not as L4's or adults except when the L4 or adult arises from the 
dauer.  This latter finding indicates that adults derived from L3's 
and dauers are not equivalent, at least in some respects.  Dominant or 
semi-dominant mutations have been detected in five genes: sqt-1, 
sqt-3,  
positions of these genes are indicated below.
[See Figure 1]
[See Figure 2]
[See Figure 3]

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Figure 3