Gene

Cell type

Cell biology

Demography

Disorders of sex development

Biology

Endocrinology

Lineage (genetic)

WNT4

Computational biology

Genetics

Transcriptome

SOX9

Spermatogenesis

Embryo

Development of the gonads

Embryonic stem cell

Population

Sociology

Andrology

Medicine

Cell

Gene expression

Sertoli cell

Wnt signaling pathway

Gonad

Sexual differentiation

Cellular differentiation

Cell Reports

Although the genetic triggers for gonadal sex differentiation vary across species, the cell biology of gonadal development was long thought to be largely conserved. Here, we present a comprehensive analysis of gonadal sex differentiation, using single-cell sequencing in the embryonic chicken gonad during sexual differentiation. The data show that chicken embryonic-supporting cells do not derive from the coelomic epithelium, in contrast to other vertebrates studied. Instead, they derive from a DMRT1+/PAX2+/WNT4+/OSR1+ mesenchymal cell population. We find a greater complexity of gonadal cell types than previously thought, including the identification of two distinct sub-populations of Sertoli cells in developing testes and derivation of embryonic steroidogenic cells from a differentiated supporting-cell lineage. Altogether, these results indicate that, just as the genetic trigger for sex differs across vertebrate groups, cell lineage specification in the gonad may also vary substantially.

Insights into Gonadal Sex Differentiation Provided by Single-Cell Transcriptomics in the Chicken Embryo