Overview
- The Science study, published Thursday, mapped gene activity cell by cell in six cortical regions from 30 adults using single-nucleus RNA sequencing, which measures which genes are switched on in individual cells.
- Sex accounted for less than 1% of overall expression differences, yet more than 3,000 genes showed sex-biased activity in at least one region and 133 did so across regions and cell types.
- The biggest gaps were on the sex chromosomes with many X genes in women escaping the usual shutoff, yet most shifts were on other chromosomes and linked to regulation by estrogen and testosterone.
- Many sex-biased genes overlapped with genetic risk factors for ADHD, schizophrenia, depression, and Alzheimer’s disease, suggesting a route to explain sex-skewed risk and symptoms.
- The authors and outside experts stressed that this is a resource, not a clinic-ready guide, and called for replication, developmental timing work, and broader samples to test causes and refine relevance.