Worm Breeder's Gazette 1(1): 22

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.

Chromosome Rearrangements

R.K. Herman

The primary goal of this work is to collect balancer chromosomes to 
facilitate the maintenance of recessive lethal mutations in 
heterozygotes.  A paper on work done at the MRC-LMB with D.  G.  
Albertson and S.  Brenner has been accepted for publication in 
'Genetics.'  In that work unlinked duplications of a part of the X 
chromosome were identified by the following procedure: N2 males were X-
irradiated (6,000-8,000 r) and mated with unc-3(E151), a sex-linked 
mutant.  The progeny were screened for wild-type males, which were 
backcrossed to unc-3.  One of the duplications derived in this way, 
Dp1, proved to be translocated to linkage group V, where it suppresses 
crossing over between the left half of the Dp1-containing chromosome 
and its homologue.  Dp1 homozygotes grow slowly and are sterile.  Dp1 
should be a useful balancer for the left half of LGV.  Four other 
duplications are associated with chromosome fragments, as observed 
cytologically by fluorescence microscopy, and tend to be lost.  At 
least some of the loss appears to occur premeiotically.  The frequency 
of loss is higher in strains homozygous for him-1.  The recombination 
frequencies between two of these duplications and the X have been 
measured: the frequencies are at least 50 times less than for X-X 
recombination in the same region.
I am currently screening for various autosomal translocations.  
Candidates have been identified and are being tested further.