To investigate the cellular events that account for the suppression of Muv phenotype, authors used Nomarski optics to examine the fates of P3.p, P4.p, and P8.p. In
let-60(
n1046gf) single mutants, 37% of these cells adopted complete or partial vulval cell fates (n = 36). By contrast, in
let-60(
n1046gf);
cdf-1(
n2527) double mutants, P3.p, P4.p, and P8.p always adopted an uninduced tertiary cell fate (n = 36). Thus, the suppression of Muv phenotype caused by
cdf-1 mutations is due to a transformation of vulval to nonvulval cell fates in P3.p, P4.p, and P8.p, and
cdf-1 appears to regulate the initial step in Pn.p cell fate determination.