Choosing male or female

Abstract

Reproductive Biology Mammals show dimorphic development with different germ cells and reproductive systems. Mullerian inhibiting substance (MIS) is key to mammalian dimorphic development. In males, the testis secretes MIS, which causes the regression of Mullerian ducts (which are the developmental rudiments for Fallopian tubes, uterus, cervix, and vagina). Using single-cell RNA sequencing, Saatcioglu et al. investigated the persistence of a small group of Misr2+ mesenchymal cells in females. They found that these cells are retained postnatally in the rodent uterus until week 37, when they recede. Misr2+ cells specify endometrial stroma during neonatal uterine development. Applying MIS postnatally inhibits these cells and prevents endometrial stroma and dysregulates paracrine signals to cause complete infertility. This work could be relevant for understanding sexual dimorphism and reproductive developmental disorders. eLife 8 , e46349 (2019).