Alder and Hancock [Public domain] via Wikimedia Commons
Despite its morphological simplicity, the sea squirt (Ciona intestinalis) shares most of its genes with vertebrates. Its embryonic development is fundamentally similar to that of vertebrates, but because the embryos are structurally simple, they are useful as models for developmental studies.
Lab Anim. (NY) 40, 264 (2011).
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