Characterization of female- and male-biased genes. For each of the 47,122 transcripts the sex effect was determined using a mixed model, resulting in 3.1% sex-biased genes. A) Transcripts were selected based on a threshold for mean expression, the percentage of sex-biased genes increases with the threshold that is used: in genes that are highly expressed there are more (up to 13%) sex-biased genes than in genes that have low expression. Nonetheless, also large male/female fold changes were observed in genes with low (B) and moderate (C) expression. D) For each transcript fold changes were computed; on the autosomes 57.7% of the sex-biased genes was female-biased, and absolute loge fold changes ranged from 0 to 0.2. E) For each chromosome, the number of male- and female-biased genes was computed, only the Y and X chromosomes were enriched for male- and female-biased genes, respectively.