Fig. 4. Most electropharyngeograms (EPGs) from ceh-2(ch4) mutants lack M3 transients. Each EPG corresponds to one pharynx pump cycle (contraction and relaxation). (A-C) Typical EPGs from wild type N2 (A) and ceh-2(ch4) (B). M3 transients are marked with asterisks. Note the longer pump duration in mutants (B). EPGs of ceh-2(ch4) worms carrying a rescue transgene have normal M3 transients (C). (D) Percentage of animals with wild-type EPGs. Recordings of 10-20 EPGs from each of 9-24 animals were classified according to the presence of M3 transients in the EPGs: all EPGs from one animal lack M3 transients (white), at least one EPG from that animal has M3 transients (hatched), or all EPGs have normal (wild type) M3 transients (black). Two independent strains carrying the rescue transgene pTRB203 show rescue. The non-rescue control strain was transgenic with pTRB204.