Fig. 8.

Growth of secondary hearts is dependent on the host embryo. Transplants in samples analysed by double-WMISH for myl7 and myl3 at stage 39 were visualised by lineage tracing (pink-light red colour). (A, B) Examples of control transplants (R20H20; GATA-4 injected reaggregates transplanted at stage 20 into host embryos at the same stage) show that cardiac tissue occupies a substantial part of the transplant. In contrast, cardiac tissue in (C) R28H20 and (D) R20H20UV (UV-ventralised hosts) transplants occupies a much smaller area (arrows). (D) Inside view of a dissected sample is presented to better show cardiac tissue (myl7, pointed by an arrow). Lineage trace that is visible from the outside is outlined. The scale bar corresponds to 100 μm. All images except the insert in (C) (showing the heart dissected from control embryo at stage 39) are at the same magnification. At least 5 samples were analysed for each treatment, with comparable results.