Extended Data Figure 7: Expression patterns of Nodal-signalling-related genes in H. magnipapillata.

a, H. magnipapillata Bmp genes exhibit a similar pattern of expression in endodermal cells at the oral side. All Activin genes show expression in the endodermal layer in the upper half of the body column, except for the head region. ActL2 shows a broader expression area than the other Activin genes do along the body length towards the foot region. Cerberus-like1 (CerL1), CerL2a and CerL2b are expressed at a high level in the endodermal layer at the base of the tentacles in mature Hydra. CerL4 was expressed in specific endodermal cells at the tip of the tentacles. Gremlin-like (GreL) showed a ubiquitous expression pattern. The Nodal target genes Pitx and FoxA were expressed in the endoderm. Prominent expression was observed at the evaginating bud tip and head region (Pitx) or the base of the tentacles (FoxA). Lhx1/5 showed clear expression at the mature and developing oral tip and peduncle. b, At the presumptive bud region (stage 1), Pitx expression was clearly demonstrated, but the other genes were under the detection limit by WISH. The first detectable expression of the ActL1, CerL1, CerL2b and FoxA genes appeared at budding stage 3.