Worm Breeder's Gazette 9(2): 82

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.

Distribution of Lethal Mutations in LGIV (right)

D.V. Clark and D.L. Baillie

Figure 1

We have isolated lethal mutations in a screen to determine the 
distribution of essential genes on LGIV (right) in the region balanced 
by nT1.  Previous work in the 1.5 m.u.  sDf2 region has identified 20 
essential genes (Rogalski, T. M.  and Baillie, D. L., 1985, MGG 
201:409-414).  Sixteen of these lie within 1 m.u.  to the left of unc-
22.  unc-22(s7)unc-31(e169)/nT1(IV);+/nT1(V) hermaphrodites were 
exposed to .012M EMS for four hours and 3398 F1's were screened for 
the absence of Unc-22Unc-31 progeny.  303 lethal strains were isolated.
Of the 283 strains analyzed so far, 164 lethals map to LGIV and 
these were retained.  This data, together with data from a similar 
screen (Donati, L.M.  et al, CSH C.  1985, p.
38), shows a frequency of lethal mutations recovered over nT1 of .078, 
with .044 on LGIV and .034 on LGV.  The distances of LGIV lethals from 
unc-22 were also determined by two-factor mapping.  Results show a 
cluster around unc 22.  This parallels the distribution of visibles on 
the 1985 C. ese lethals are now being left-
right positioned relative to unc-22 by employing a set of three 
deficiencies which define seven zones (sDf2, sDf21, and mDf7, which 
was kindly supplied by Teresa Rogalski).  In the figure below, the 
height of the bars corresponds to the number of lethal alleles on LGIV 
which map in the 1 m.u.  interval ending with the distance indicated.
[See Figure 1]

Figure 1