Beyond chromosomes: Sex matters in gene expression

More than a third of human genes show sex-based differences in at least one type of tissue, a new study from the Genotype-Tissue Expression Consortium concludes, potentially explaining why biological processes look different in males and females, including immune responses and cancer. GTEx found modest but ubiquitous variations, but a commentary appearing with the study notes bias in the samples behind the research. Two-thirds came from men, the average age was 50, and nearly 85% were from white people of European ancestry. “Given these limitations of the samples, it is even more surprising — and should be motivating to human geneticists — how much interindividual variation is observed,” the commentary author writes.