Fig. 6

Germ cell development of Pe. nuntia. a Hybridized slide section showing the Pn-vasa expression in the big cell cluster at the distal end of the parapodium. d,g, j Pn-vasa positive cells observed from the trunk area of the parapodium down to the coelomic cavity. b Thin section (5 μm) of the parapodium stained with hematoxylin and eosin showing the big cell cluster. c Cells from figure b (box frame) at higher magnification (1,000×) showing the cell’s condensed chromosomes (arrows) and pink-colored granular-like structures. f, i, l The corresponding hematoxylin and eosin stain of the Pn-vasa positive cells. Condensed chromosomes are visible in cell clusters (f and i). e, h, k Sense control experiment. Note: Figure d is taken from Fig. 4C, while figure g is taken from other parapodium source. Figure k is also taken from Fig. 5 (inset)