A comparative analysis of sex differences across a variety of mammals published in Science this week reveals hundreds of genes with conserved sex-biased expression and offers new insights into into the molecular origins and evolution of sexual dimorphism. In the study, researchers studied RNA sequencing data from male and female humans, macaques, mice, rats, and dogs across 12 tissues. "In each tissue, we identified hundreds of genes with conserved sex-biased expression," which contribute to the trait differences between sexes, they write. For instance, when combined with genomic analyses of human height, the findings explain about 12 percent of the difference in height between females and males. However, the authors note that most sex-biased expression arose during the mammalian radiation, "which suggests that careful attention to interspecies divergence is needed when modeling human sex differences."
A new study appearing in Science Advances this week sheds light on the activity of a SNP linked to prostate cancer risk. A role for the SNP in prostate cancer has been established by previous genome-wide association studies, but the mechanisms underlying this association were unknown. In the study, investigators show that the variant is located in an enhancer active in prostate cancer cells. Meanwhile, deletion of the enhancer from prostate tumor cells resulted in decreased tumor initiation, tumor growth, and invasive migration, as well as a loss of stem-like cells. Using capture chromosome conformation capture and RNA sequencing, they identify genes on the same and different chromosomes as targets regulated by the enhancer, and the researchers show that expression of individual candidate target genes in an enhancer-deleted cell line rescued different aspects of tumorigenesis.