Figure 4.

Behavioral and hair cell electrophysiological characteristics of tmc2b^cwr2 tmc2a^cwr3 double and tmc2b^cwr8 tmc1^cwr4 tmc2a^cwr6 triple mutants. Schematics of chromosome 5 with relative positions of tmc genes and associated mutant alleles for the tmc2b^cwr2 tmc2a^cwr3 double mutant (A) and the tmc2b^cwr8 tmc1^cwr4 tmc2a^cwr6 triple mutant (B). (C) Graph of the mean percentages of mutant and control zebrafish that exhibited a C-start response when presented with vibrational stimuli ± SEM. Each data point represents the percentage of positive responses a larva had in a trial of 20 stimuli (n_tmc2b^cwr2/+_tmc2a^cwr3/+ = 5 (controls), n_tmc2b^cwr2_tmc2a^cwr3 = 15, n_tmc2b^cwr8_tmc1^cwr4_tmc2a^cwr6 = 15). Tmc2b^cwr2 tmc2a^cwr3 double mutant = 39 ± 5.6%, tmc2b^cwr8 tmc1^cwr4 tmc2a^cwr6 triple mutant = 2.0 ± 0.96%. Representative recordings of microphonic potentials measured from the ears of (D) double- and (E) triple-mutant animals. (F, G) Graphs of mean microphonic potentials from otocysts of 7–10 dpf larvae are displayed. (F) Mean potential of tmc2b^cwr2 tmc2a^cwr3 double mutants ± SEM = 0.42 ± 0.07 μV (n = 10), mean potential of heterozygotes (tmc2b^cwr2/+ tmc2a^cwr3/+) = 96 ± 3.5 μV (n = 12). (G) No potentials were observed in tmc2b^cwr8 tmc1^cwr4 tmc2a^cwr6 triple mutants (n = 10), mean potential of wild-type controls = 82 ± 3.4 μV (n = 10). Mann–Whitney test, ^****P < 0.0001.