Meeting Abstract

P1.137  Wednesday, Jan. 4  Sequencing and analysis of the gastrula transcriptome of the brittle star Ophiocoma wendtii VAUGHN, R.*; GARNHART, N.; THOMAS, W.K.; GAREY, J.R.; LIVINGSTON, B.T.; Univ. of South Florida; Univ. of New Hampshire; Univ. of New Hampshire; Univ. of South Florida; California State Univ., Long Beach

The gastrula stage represents the point in development at which the three primary germ layers diverge. At this point the gene regulatory networks that specify the germ layers are established and the genes that define the differentiated states of the tissues have begun to be activated. These networks have been well characterized in sea urchins, but not in other echinoderms. We have sequenced and characterized the gastrula transcriptome of the brittle star Ophiocoma wendtii. The transcriptome is composed of 99,285 sequences of which some 12,530 can be identified when compared to existing databases. When compared to the sea urchin Strongylocentrotus purpuratus UniGene set there are 6931 genes that are shared with those expressed in the O. wendtii gastrula transcriptome. We have characterized the functional classes of genes present in the transcriptome and compared them to those found in sea urchin. We then examined which members of the germ layer specific gene regulatory networks of S. purpuratus are expressed in the O. wendtii gastrula. The brittle star expresses genes representing all functional classes at the gastrula stage. Brittle stars and sea urchins have comparable numbers of each class of genes, and share many of the genes expressed at gastrula. Examination of the genes that are utilized in sea urchin germ layer specification in the brittle star reveals the conservation of key regulatory components as well as genes that were either lost or co-opted in the two groups.