biostudies-literatureUnknown104(37)Hwang JSCell lineages of cnidarians including Hydra represent the fundamental cell types of metazoans and provides us a unique opportunity to study the evolutionary diversification of cell type in the animal kingdom. Hydra contains epithelial cells as well as a multipotent interstitial cell (I-cell) that gives rise to nematocytes, nerve cells, gland cells, and germ-line cells. We used cDNA microarrays to identify cell type-specific genes by comparing gene expression in normal Hydra with animals lacking the I-cell lineage, so-called epithelial Hydra. We then performed in situ hybridization to localize expression to specific cell types. Eighty-six genes were shown to be expressed in specific cell types of the I-cell lineage. An additional 29 genes were expressed in epithelial cells and were down-regProceedings of the National Academy of Sciences of the United States of America14735-40https://www.ebi.ac.uk/biostudies/studies/S-EPMC1963347biostudies-literatureThe evolutionary emergence of cell type-specific genes inferred from the gene expression analysis of Hydra.PMC1963347Ohyanagi HOsato NHayakawa SIkeo KGojobori THwang JSFujisawa TDavid CNNishimiya-Fujisawa CfalseThe evolutionary emergence of cell type-specific genes inferred from the gene expression analysis of Hydra.Cell lineages of cnidarians including Hydra represent the fundamental cell types of metazoans and provides us a unique opportunity to study the evolutionary diversification of cell type in the animal kingdom. Hydra contains epithelial cells as well as a multipotent interstitial cell (I-cell) that gives rise to nematocytes, nerve cells, gland cells, and germ-line cells. We used cDNA microarrays to identify cell type-specific genes by comparing gene expression in normal Hydra with animals lacking the I-cell lineage, so-called epithelial Hydra. We then performed in situ hybridization to localize expression to specific cell types. Eighty-six genes were shown to be expressed in specific cell types of the I-cell lineage. An additional 29 genes were expressed in epithelial cells and were down-reg2007-01-01T00:00:00Z2007 Sep2026-05-01T05:30:06.724Z2026-04-29T03:08:31.537ZS-EPMC19633471776643710.1073/pnas.0703331104