Expression patterns of hairy, even-skipped, and runt in the spider Cupiennius salei imply that these genes were segmentation genes in a basal arthropod.
There is an ongoing discussion on whether segmentation in different phyla has a common origin sharing a common genetic program. However, before comparing segmentation between phyla, it is necessary to identify the ancestral condition within each phylum. Even within the arthropods it is not clear which parts of the genetic network leading to segmentation are conserved in all groups. In this paper, we analyze the expression of three segmentation genes of the pair-rule class in the spider Cupiennius salei. Spiders are representatives of the Chelicerata, a monophyletic basic arthropod group. We find that in spider embryos, the orthologues for the Drosophila primary pair-rule genes hairy, even-skipped, and runt are expressed in stripes in the growth zone, where the segments are forming, suggesting a role for these genes in chelicerate segmentation. These data imply that the involvement of hairy, even-skipped, and runt in arthropod segmentation is an ancestral character for arthropods and is not restricted to a particular group of insects.
Damen
W G
WG
Department of Evolution Genetics, Institut für Genetik, Universität zu Köln, Weyertal 121, D-50931 Cologne, Germany. damen@uni-koeln.de
Weller
M
M
Tautz
D
D
D000818:Animals; D001426:Bacterial Proteins; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics*; D029721:Drosophila Proteins; D019143:Evolution, Molecular; D005260:Female; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics*; D019476:Insect Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012097:Repressor Proteins / Q000235:genetics*; D013112:Spiders / Q000145:classification* / Q000235:genetics* / Q000254:growth & development; D014157:Transcription Factors
D001426:Bacterial Proteins; D051792:Basic Helix-Loop-Helix Proteins; D017931:DNA Primers; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D019476:Insect Proteins; D009687:Nuclear Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C052837:eve protein, Drosophila; C080833:run protein, Drosophila; C061841:hairy protein, insect