Figure 2.—

Higher evolutionary rates of male-specific genes in the melanogaster group. (A) d_S, d_N, and ω estimates of genes expressed in head, ovary, testis, expressed in seminal fluid and female reproductive tract, and involved in spermatogenesis and oogenesis. Error bars represent 95% confidence intervals. T, testis specific; O, ovary specific; TH, testis and head; TO, testis and ovary; H, head specific; OH, ovary and head; TOH, testis, ovary, and head; Sp, spermatogenesis; Oo, oogenesis. (B) Proportion of gene categories among the top 10% of the most rapidly evolving genes. Proportions of genes in each category among the top 10% genes were compared to the initial proportions in the whole data set using a χ² test and a Bonferroni correction. ns, nonsignificant. *P < 0.05, ***P < 0.001. (C) Average d_S and d_N for testis-, ovary-, and head-specific genes across lineages. Testis-specific genes show significantly higher d_N in all lineages (Tukey HSD test, P < 0.001).