Biology
Document Type
Article
Abstract
Background: Annelids and arthropods each possess a segmented body. Whether this similarity represents an evolutionary convergence or inheritance from a common segmented ancestor is the subject of ongoing investigation.Methods: To investigate whether annelids and arthropods share molecular components that control segmentation, we isolated orthologs of the Drosophila melanogaster pair-rule genes, runt, paired (Pax3/7) and eve, from the polychaete annelid Capitella teleta and used whole mount in situ hybridization to characterize their expression patterns.Results: When segments first appear, expression of the single C. teleta runt ortholog is only detected in the brain. Later, Ct-runt is expressed in the ventral nerve cord, foregut and hindgut. Analysis of Pax genes in the C. teleta genome reveals the presence of a single Pax3/7 ortholog. Ct-Pax3/7 is initially detected in the mid-body prior to segmentation, but is restricted to two longitudinal bands in the ventral ectoderm. Each of the two C. teleta eve orthologs has a unique and complex expression pattern, although there is partial overlap in several tissues. Prior to and during segment formation, Ct-eve1 and Ct-eve2 are both expressed in the bilaterial pair of mesoteloblasts, while Ct-eve1 is expressed in the descendant mesodermal band cells. At later stages, Ct-eve2 is expressed in the central and peripheral nervous system, and in mesoderm along the dorsal midline. In late stage larvae and adults, Ct-eve1 and Ct-eve2 are expressed in the posterior growth zone.Conclusions: C. teleta eve, Pax3/7 and runt homologs all have distinct expression patterns and share expression domains with homologs from other bilaterians. None of the pair-rule orthologs examined in C. teleta exhibit segmental or pair-rule stripes of expression in the ectoderm or mesoderm, consistent with an independent origin of segmentation between annelids and arthropods. © 2012 Seaver et al; licensee BioMed Central Ltd.
Publication Title
EvoDevo
Publication Date
4-18-2012
Volume
3
Issue
1
ISSN
2041-9139
DOI
10.1186/2041-9139-3-8
Keywords
Capitella, Eve, Pax3/7, Polychaete, Runt, Segmentation
Repository Citation
Seaver, Elaine C.; Yamaguchi, Emi; Richards, Gemma S.; and Meyer, Néva P., "Expression of the pair-rule gene homologs runt, Pax3/7, even-skipped-1 and even-skipped-2 during larval and juvenile development of the polychaete annelid Capitella teleta does not support a role in segmentation" (2012). Biology. 391.
https://commons.clarku.edu/faculty_biology/391
Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.
Copyright Conditions
Seaver, E. C., Yamaguchi, E., Richards, G. S., & Meyer, N. P. (2012). Expression of the pair-rule gene homologs runt, Pax3/7, even-skipped-1 and even-skipped-2 during larval and juvenile development of the polychaete annelid Capitella teleta does not support a role in segmentation. EvoDevo, 3, 1-18. https://doi.org/10.1186/2041-9139-3-8
