X-linkage of D. melanogaster broadly and narrowly expressed genes. (Barplots) Percent of D. melanogaster genes with narrow expression (τ > 0.7) in each of four sex-limited tissues, with testis-biased expression and detectable in the sperm proteome (testis-SP), narrowly expressed in any of 14 tissues (narrow), narrowly expressed in one of 10 non-sex-limited tissues (no sex) or broadly expressed genes (τ ≤ 0.4) that are X-linked. (Dashed lines) Percent of the entire genome that is X-linked. (*) Observed values that significantly differ from the expectation based on the size of the X chromosome as determined by a permutation test; (**) P < 0.01, (***) P < 0.001.
