TABLE 2

Germline spontaneous mutation frequency is not increased in a him-14 mutant

GenotypeFlask no.Plates with LevR/total platesf (0)Mutation frequency (LevR/gamete)Spontaneous LevR mutations/gamete
xol-1(y9)10/1810
24/180.781.3 × 10−5
31/180.943.2 × 10−6
43/180.839.5 × 10−6
54/180.781.3 × 10−6
63/170.821.0 × 10−68.1 ± 5.4 × 10−6
him-14(it44); xol-1(y9)14/200.801.2 × 10−5
23/200.858.6 × 10−6
32/200.905.5 × 10−6
42/200.905.5 × 10−6
54/200.801.2 × 10−5
66/190.682.0 × 10−51.1 ± .54 × 10−5
  • The frequency of spontaneous germline mutations conferring levamisole resistance (LevR) was assessed in him-14 mutantworms [him-14(it44); xol1(y9)] and control [xol-1(y9)] worms. For both genotypes, six independent liquid cultures, each containing ~3 × 106 synchronized L1 larvae, were shifted to the restrictive temperature (23°). The frequency of LevR mutations among the gametes of these shifted animals was measured by plating multiple aliquots of their F1 progeny and testing for the segregation of resistant worms in the subsequent generation, as described in materials and methods. Mutation frequencies for each independent culture were calculated as: [m, the mean number of spontaneous mutations per plate]/19,000 [= number of haploid genomes represented per plate]. m was calculated using the Poisson equation f(0) = e−m, where f(0) = the fraction of the plates from a given culture that did not contain a LevR mutant.