Fig. 3: Thermosensitive stochastic sex determination of P. mayeri.
Comparison of sequence read coverage depth between the sexes of P. mayeri (a), P. pacificus (b) and P. exspectatus (c), respectively. Average log2 coverage of 100-kb sliding windows is normalised for each individual and median of the normalised coverage were presented as a line. The area between the first and third quartiles were shown in the light-colour ribbon. Colored bars on the axes represent chromosome elements corresponding to NigonE (orange), NigonN (purple) and NigonX (green). P. pacificus and P. exspectatus have 6, XO and 6, XY karyotype, respectively, and exhibit log2 coverage difference specifically in the ancestral X chromosome regions (i.e. NigonX). d The number of hermaphrodite and male progeny in crosses between different strains of P. mayeri. Only 7 out of 10 crossing experiments yielded cross progeny. Test of temperature effects on the percentage of male production in the P. mayeri strains RS5460B (e, N = 15 each) and RSA035 (f, N = 10 each). Each jitter point represents the male ratio of a single biological replicate with the red bar indicating the average across replications. Statistic tests were conducted with GLMM for pairwise comparison. For RS5460B, the effects of temperature differences on the log odds (and their 95% confidence intervals) were estimated as 21.69 ([20.9, 33.5]), 1.82 ([1.09, 2.92]), and 24.1 ([23.6, 35.4]) for 15 °C vs. 20 °C, 20 °C vs. 25 °C, and 15 °C vs. 25 °C, respectively. Those χ2 statistics are 8.80, 15.3 and 33.4, respectively. Those Bonferroni-adjusted p-values are 9.03 × 10−3, 2.78 × 10−4 and 2.24 × 10−8, respectively. For RSA035, the effects of temperature differences on the odds ratio (and their 95% confidence intervals) are estimated as 0.966 ([0.326, 1.77]), 0.852 ([0.302, 1.45]), and 1.81 ([1.18, 2.63]) for 15 °C vs. 20 °C, 20 °C vs. 25 °C, and 15 °C vs. 25 °C, respectively. Those χ2 statistics are 6.68, 8.93 and 23.4, respectively. Those Bonferroni-adjusted p-values are 2.92 × 10−2, 8.39 × 10−3 and 3.98 × 10−6, respectively. The degrees of freedom of all tests are 1. The Bonferroni-adjusted p-values are one-sided due to goodness-of-fit test and represented as stars (*p < 0.05, **p < 0.01, ***p < 0.001).
