Background Determining Aβ-PET status is crucial for Alzheimer’s disease trials. Standard uptake value ratio (SUVR) using a reference region common semi-quantitative technique. Sex differences in regional blood flow and white matter (WM) could impact SUVR differentially depending on the region. It important to understand how methodological factors can influence derived Aβ status. Method Individu...

In humans and other mammals with XX females and XY males, the Y bears a gene (SRY) that induces testis differentiation in the embryo and switches on hormones that masculinize it. The human X has more than 1500 genes, but the tiny Y is a genetic wasteland and bears only 45 protein-coding genes, most active only in testis. To discover how human sex chromosomes got to be so weird, we compared the ...