Evolution of the bilaterian body plan: what have we learned from annelids?
Annelids, unlike their vertebrate or fruit fly cousins, are a bilaterian taxon often overlooked when addressing the question of body plan evolution. However, recent data suggest that annelids offer unique insights on the early evolution of spiral cleavage, anteroposterior axis formation, body axis segmentation, and head versus trunk distinction.
Shankland
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Section of Molecular Cell and Developmental Biology, and Institute of Cellular and Molecular Biology, University of Texas, Austin, TX 78712, USA. hastypig@mail.utexas.edu
Seaver
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EC
D000818:Animals; D000845:Annelida / Q000033:anatomy & histology* / Q000196:embryology* / Q000235:genetics; D005075:Biological Evolution; D019521:Body Patterning / Q000235:genetics*; D004625:Embryo, Nonmammalian; D005801:Genes, Homeobox