MOESM9 of From spiral cleavage to bilateral symmetry: the developmental cell lineage of the annelid brain

Additional file 9: Figure S1. Comparing the cell lineage among multiple embryos. This supplementary figure provides details about the comparison of the cell lineage among multiple embryos and identifying corresponding cells. (A-D’) The comparison between the clonal domains revealed by injections of h2a-rfp mRNA into a single blastomere and the clonal domain of the corresponding blastomere highlighted in red using the reference lineage movie at 32 hpf. (E) Comparison of the clonal domains originating from the cells present at 13 hpf in three different embryos. (F) Identification of corresponding cells between embryos: Multiple features (number of descendants, time till next cell division, relative cell position of each daughter cell) are extracted from the tracking information at each cell division. The feature arrays are compared between embryos to score the similarity and identify corresponding cells. For more details, see Materials and methods. (G-G’) The problem of assessing the differences between incomplete lineage trees: Due to the asynchrony in cell division timing, some of the corresponding divisions can happen after the last frame of a given movie (dashed line) – e.g. the magenta lineage within the blue domain in Lineage 1 divides later and therefore does not represent a real difference in cell division pattern. In contrast, the red cells within the green sublineage do not divide in Lineage 2 and therefore represent a real difference. (H) The average maximal difference in timing of corresponding cell divisions across three embryos increases with time, reaching around 2.5 h at 30 hpf. The maximal difference in timing was calculated as the difference between the time point at which the corresponding division occurred earliest among the three embryos, and the latest among the three embryos. The average difference was calculated from all corresponding cell divisions happening within the given hour post fertilization.