Progression through meiosis is characterized by a bifurcation point.

(A) Pseudotime trajectory analysis of 4,550 meiotic cells identifies two lineages bifurcated from a branch point (dashed circle). Piecharts show the percentages of each cell type in the two lineages. (B) Scaled expression of genes in meiosis II (18 genes; upper panel) and one representative gene LOC727405/mud (lower panel). Cells are binned with a width of one pseudotime unit. For every gene, the y-axis value corresponds to z-scored deviation from its mean scaled expression in a bin of cells. For Amel, the location of the branch point (between dashed lines) was estimated from the overlapped pseudotime points among the three different branches. For Dmel, the dashed lines represent a transition point estimated from the overlapped pseudotime points between late spermatocytes and early spermatids in the scRNA-seq data of [50]. (C) A pseudotime-ordered heatmap from trajectory in panel A with 2,247 differentially expressed genes (adjusted p-value < 0.05 calculated by Monocle2) between the two bifurcated lineages. Hierarchical clustering reveals four major gene groups with distinct patterns. (D) GO and KEGG terms with top enrichment with genes in each hierarchical group of panel C.