Origins of bilateral symmetry: Hox and dpp expression in a sea anemone.
Over 99% of modern animals are members of the evolutionary lineage Bilateria. The evolutionary success of Bilateria is credited partly to the origin of bilateral symmetry. Although animals of the phylum Cnidaria are not within the Bilateria, some representatives, such as the sea anemone Nematostella vectensis, exhibit bilateral symmetry. We show that Nematostella uses homologous genes to achieve bilateral symmetry: Multiple Hox genes are expressed in a staggered fashion along its primary body axis, and the transforming growth factor-beta gene decapentaplegic (dpp) is expressed in an asymmetric fashion about its secondary body axis. These data suggest that bilateral symmetry arose before the evolutionary split of Cnidaria and Bilateria.
Finnerty
John R
JR
Department of Biology, Boston University, 5 Cummington Street, Boston, MA 02215, USA.
Pang
Kevin
K
Burton
Pat
P
Paulson
Dave
D
Martindale
Mark Q
MQ
D000595:Amino Acid Sequence; D000818:Animals; D019521:Body Patterning; D004707:Endoderm / Q000502:physiology; D020440:Gene Duplication; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D005796:Genes; D005801:Genes, Homeobox; D017403:In Situ Hybridization; D007814:Larva / Q000235:genetics / Q000254:growth & development; D008969:Molecular Sequence Data; D010802:Phylogeny; D012615:Sea Anemones / Q000033:anatomy & histology* / Q000196:embryology / Q000235:genetics* / Q000254:growth & development