Single-cell RNA-seq of amniotic fluid provides unique insight into fetal development

Single-cell RNA-seq of amniotic fluid from seven healthy euploid second-trimester pregnancies identifies an atlas of 11,414 fetal human cells, dominated by fetal skin cells.

• Why it matters: Human fetal tissue is hard to access, so there is a need for a practical, ethical source that captures viable fetal cell types and their developmental changes.
• What they did: scRNA-seq was performed on AF collected at 15–25 weeks’ gestation, using a modified transcriptome to reduce sparsity, then supervised annotation, clustering, marker analysis, and gestational-age differential expression/proportion tests.
• The result: Fetal skin cells were most abundant, and cell-type composition shifted with gestational age, including increased lung epithelium coinciding with the canalicular phase; fetal skin DGE recapitulated second-trimester developmental processes.