Question

Cnidarians are diploblasts and lack mesoderm. Describe how you could use this characteristic to investigate the evolutionary origins of mesoderm in other animals.

Answer 1

Am - Mesod the Radiation the evolution of ea plans in the diplo by The sea anemon la permitting complex body Sila terian Anime non-bilaterias ongeam chidaria. The one, Corals, hydra's 8 group of nidarian. s. stic animals are generally stigate the origin the developmen genes from Nemato log's are Mesoderm played a crucial role in the Re the triploblastic Bantena, Bilateria, pert lution of larger and more complex In the diploblastic, non- bilateria sea anemone Nematos tellais a non- nimal, a member of the phylum Phylum Cnidaria ( Sea Anemont, Cora and Telly fish) is the likely sisted he triploblastic Bilateria. Cnidaria posses Bring endo deom and ectoderm but lacking mesoderm. To Investigate the on og triploblasty, we studied the dered - tal expression of seven genes from - stella whose bilaterian homo logis a implicated in mesodermal specification the diffrentiation of mesodermal cell types ( twist, Snail A Snail B) forkhea mefa, a GATA transcription factor and a LIM transcription factor). Except for meta, the expression of these genes is largely restricted to the endodermal layer, the Gastrodermis, meta, the is restricted to the endoderm. The temporal and spatial expression of these mesoderm genes suggests that they may play a xale in germ dayer specification, furthermore the predominantly endodermal expresson of these genes reinforces the hypothesis that the mesoderm and endoderm of triplo blaste animal. 8 could be derived from the Endodon of a diploblastic ancestor. ley