Divergence of ectodermal and mesodermal gene regulatory network linkages in early development of sea urchins
Citation: Erkenbrack, E. M. (2017). Divergence of ectodermal and mesodermal gene regulatory network linkages in early development of sea urchins. Proceedings of the National Academy of Sciences, 113(46), E7202-E7211.
Sea urchins (echinoids) consist of two subclasses, cidaroids and euechinoids. Research on gene regulatory networks (GRNs) in the early development of three euechinoids indicates that little appreciable change has occurred to their linkages since they diverged ∼90 million years ago (mya). I asked whether this conservation extends to all echinoids. I systematically analyzed the spatiotemporal expression and function of regulatory genes segregating euechinoid ectoderm and mesoderm in a cidaroid. I report marked divergence of GRN architecture in early embryonic specification of the oral–aboral axis in echinoids. Although I found evidence for diverged regulation of both mesodermal and ectodermal genes, comparative analyses indicated that, since these two clades diverged 268 mya, mesodermal GRNs have undergone significantly more alterations than ectodermal GRNs.

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