Worm Breeder's Gazette 4(1): 41

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.

Studies on the X-chromosome of Panagrellus redivivus

D. Burke, S. Schulz, M. Samoiloff

Mutants on the X-chromosome of the dioecious Panagrellus redivivus 
have been isolated and mapped.  Four uncs and a long have been 
maintained in both sexes.  Paralysed, twitchers and dumpies have been 
obtained, but males fail to mate.  Three of the uncs have reduced 
mobility or coordination, while the fourth unc contracts when tapped 
on the head, but will not reverse.  The long mutant is approximately 
30% longer than wild type, with no decrease in body width, Recently a 
new phenotype, skinny, more than 100% longer and 25% thinner has been 
isolated by Yvonne Jordan.
The frequency of mutation using standard EMS mutagenesis of L4s is 4.
4 X 10+E-4 mutations per visible locus.  The number of essential genes 
on the P.  redivivus X-chromosome is calculated at 320 on the basis of 
the frequency of lethal mutations corrected for double events.
The gamma-irradiation induced mutation rate is 9 X 10+E-7 mutations 
per locus per rad, using a dose-rate of 4.5 Kr/min. Genetically marked 
L2s were exposed to doses of gamma radiation varying from 5 to 150 Kr. 
Using target theory applied to males it was calculated that 180, 130 
and 1800 X-linked genes in the total P.  redivivus genome are required 
to complete the second, third and final moult, respectively.  The 
kinetics of the failure of females to develop after gamma-irradiation 
was more indicitive of chromosome breaks rather than point mutation.