Single-cell Next Generation Sequencing (scNGS) facilitates analysis of gonadal single cells transcriptomes and revealed germ cell heterogeneity

The unraveling of heterogenous cell populations, — previously masked in bulk transcriptome measurements — are made possible through analysis of single-cell transcriptomics. The goals of this study are to examine single-cell NGS-derived gonadal cell transcriptome profiling and to evaluate heterogeneity of gonadal germ cells in avian species. We performed single-cell RNA sequencing using embryonic gonadal cells of HH stage 28 from male and female zebra finches. We identified 12,489 male transcripts and 10,046 female transcripts. We annotated 9 different cell types from a total of 20 clustered single cells and identified that primordial germ cells, which have been considered as single population, can be distinguishable into three subtypes. The three PGC subtypes were specifically enriched for genes with expression patterns related to germness or pluripotency, suggesting functional differences in PGCs according to the three subtypes. Our study represents the first single-cell RNA seq analysis of gonadal transcriptomes in zebra finch. Our results revealed the first heterogeneity and intrinsic changes of gonadal primordial germ cells, which have hitherto been considered as a single population in avian species. We conclude that single-cell RNA seq based transcriptome analysis would offers new perspectives on avian primordial germ cells. Gonadal cells profiling of male and female zebra finches at single cell level