Fig. 2

Clonal Analysis Identifies Nine Distinct Lineage Classes in the Zebrafish Fin

(A) A Tol2 transposon lineage marker was injected into one or two cell embryos as previously described (Tu and Johnson, 2010). A highly mosaic embryo is indicative of transposon integration.

(B) An example of caudal fin (dorsal half) with mosaic GFP expression. This fin has three types of labelings: three patches of labeled epidermis (dotted line), labeled osteoblasts in three fin rays (arrows), and a string of labeled lateral line neuromasts (arrowhead). Single asterisk indicates reflection from white cells (Johnson et al., 1995) at the tip of the dorsal lobe. Double asterisks indicate labeled scale (not part of the fin) on the tail of the fish.

(C) Analysis of co-occurrence of GFP-labeled cell types. The first column lists the different cell types in the fin, with the number of fins carrying the labeled cell type in the data set of 116 mosaic caudal fins. Numbers shown in matrix cells indicate the co-occurrence of each cell type as percentage of total number of fins with labeled cell type in the first column. For example, within the 71 fins carrying labeled epidermis, 7.0% of them also carried labeled melanocytes, which is the observed co-occurrence between the two cell types. Comparing that to the expected co-occurrence (predicted by multiplying the percentage of each cell type) by using a chi-square test yields a p value indicating that the difference is not statistically significant (denoted by light-blue shading); thus, the epidermis and melanocytes are not significantly associated and most likely arise from different FSCs. The same chi-square test was carried out for all pairwise combinations of any two cell types in the fin. p values were calculated to determine whether the associations were significant. Light blue indicates nonsignificant association, whereas yellow shows significant association. The multiple testing-adjusted threshold for 95% significance is p = 0.0009.

(D) Labeled intraray glia clone. Arrow points to the intraray nerve with labeled glia. Asterisk indicates strong autofluorescence from the xanthophores. Thin gray line outlines the fin ray and the joints.

(E–G) Labeled lateral line clone (E). Arrow points to a GFP⁺ neuromast, and arrowhead points to GFP⁺ interneuromast glia. Notice lateral line resides in the space between fin rays. Osteoblast clone (F) looks like a sheet of cells covering the mineralized bone matrix. Dermal fibroblast clone (G) appears more punctate, and encased between the hemirays, and GFP signal is excluded from where the artery lies. Notice that labeled osteoblast clone and dermal fibroblast clone have clearly different appearances in high magnification (F′ and G′).

(H) Vascular clone containing both artery (arrowhead) and vein (arrows).

(I) Labeled epidermis (skin) clone (outlined by dotted line). Note that this epidermis clone has both proximal and distal boundaries. Asterisk indicates reflection from white cells.

(J) Labeled resident blood cells (arrowhead).

(K) Neutral red (macrophage marker) staining of resident blood clone ([Ellett et al., 2010] and [Winckler, 1974]). Green indicates GFP from live fish. Red shows neutral red staining. Scale bars, 0.2 mm. See also Figure S1.