Fig. 3. Zebrafish PGCs migrate actively. (A-F) Fluorescent pictures taken at the indicated intervals from a time-lapse movie showing migrating PGCs during early somitogenesis in a wild-type embryo injected with GFP-nos1-3'UTR and EGFP-F-globin marking the outlines of somatic cells. The full movie can be found at http://dev.biologists.org/supplemental/ (Movie 1). Individual PGCs are marked by colored asterisks and a single somatic cell by a green arrow. Note that the PGCs move extensively relative to the somatic mesodermal cells. The apparent cell shape changes of somatic cells seen in A-F are largely due to different focal planes at which the pictures were taken to keep the PGCs in focus. (G-I) Fluorescent pictures taken at the indicated intervals from a time-lapse movie showing migrating PGCs during mid-somitogenesis in a wild-type embryo injected with EGFP-F-nos1-3'UTR marking the outlines of PGCs. The full movie can be found at http://dev.biologists.org/supplemental/ (Movie 2). Note the highly dynamic processes extended by the PGC on the left side.