Prestin-CreER^T2 knockin homozygous mice exhibit large inter- and intra-subject variation in ABR thresholds.

<p><b>A</b> A scatter plot shows the distribution of the ABR thresholds of individual ears in the Prestin-CreER^T2 mice (+/+ and +/-) and the wild-type mice. One dot represents the average threshold of one ear calculated from the four tested frequencies. Notice that the ABR thresholds of the homozygous mice are more dispersedly distributed, from 21 to 81 dB SPL. By contrast, the thresholds of the heterozygous mice and the wild-type mice are much less diverse (25–51 dB for the wild-type mice and 21–54 dB for the heterozygous mice). The three lines in each group indicate the mean and ± standard deviation. <b>B</b> Comparison of the values of coefficient of variation among the three groups of mice. Homozygous mice display relatively larger values compared with those of the heterozygous and wild-type mice for all four tested frequencies. <b>C</b> Comparison of the levels of the two ear differences (the right ear vs. the left ear of the same animal) in the average of ABR thresholds of the four tested frequencies among the three groups of mice. The threshold differences between the two ears in the homozygous mice is significantly greater than those observed for the heterozygous mice or the wild-type mice (One-way ANOVA, <i>F_2,63 = </i>20.52, <i>P</i><0.001; *** indicates <i>P</i><0.001 tested by Tukey test). n: the number of the animals used for each group.