Barnacle duplicate <i>engrailed</i> genes: divergent expression patterns and evidence for a vestigial abdomen

Gibert, Jean‐Michel; Mouchel-Vielh, Emmanuèle; Quéinnec, Éric; Deutsch, Jean S.

doi:10.1046/j.1525-142x.2000.00059.x

Cited by 41 publications

(57 citation statements)

References 52 publications

(68 reference statements)

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“…This brought molecular evidence for the presence of a vestigial abdomen in cirripede larvae. (62,63) We also found morphological evidence of a truly segmented, but still tiny, tagma in naupliar larval stages. (64) No abdA gene has been found in any of the three cirripede species studied (Fig.…”

Section: Hox Genes and The Maxilliped Issuementioning

confidence: 61%

Hox genes and the crustacean body plan

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Mouchel-Vielh

2003

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The Crustacea present a variety of body plans not encountered in any other class or phylum of the Metazoa. Here we review our current knowledge on the complement and expression of the Hox genes in Crustacea, addressing questions related to the evolution of body architecture. Specifically, we discuss the molecular mechanisms underlying the homeotic transformation of legs into feeding appendages, which occurred in parallel in several branches of the crustacean evolutionary tree. A second issue that can be approached by the comparative study of Hox genes and their expression in the Crustacea bears on the homology of the abdomen. We discuss whether the so-called "abdominal" tagma of the crustaceans is homologous to the abdomen of insects. In addition, the homology of the abdomen between malacostracan and non-malacostracan crustaceans has also been questioned. We also address the question of the molecular developmental basis of the apparent lack of an abdomen in barnacles. We discuss these issues in relation to the problem of constraint versus adaptation in evolution.

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Section: Hox Genes and The Maxilliped Issuementioning

confidence: 61%

Hox genes and the crustacean body plan

Deutsch

Mouchel-Vielh

2003

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“…In situ hybridisation was carried out on stage L1-L3 Artemia larvae, as described previously (Gibert et al, 2000;Mitchell and Crews, 2002). …”

Section: Afsalmentioning

confidence: 99%

Posterior patterning genes and the identification of a unique body region in the brine shrimpArtemia franciscana

et al. 2003

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All arthropods share the same basic set of Hox genes, although the expression of these genes differs among divergent groups. In the brine shrimp Artemia franciscana, their expression is limited to the head,thoracic/trunk and genital segments, but is excluded from more posterior parts of the body which consist of six post-genital segments and the telson (bearing the anus). Nothing is currently known about the genes that specify the identity of these posterior structures. We examine the expression patterns of four candidate genes, Abdominal-B, caudal/Cdx, even-skipped/Evx and spalt, the homologues of which are known to play an important role in the specification of posterior structures in other animals. Abdominal-B is expressed in the genital segments of Artemia, but not in the post-genital segments at any developmental stage. The expression of caudal, even-skipped and spalt in the larval growth-zone suggests they may play a role in the generation of body segments (perhaps comparable with the role of gap and segmentation genes in insects), but not a direct role in defining the identity of post-genital segments. The expression of caudal at later stages suggests a role in the specification of anal structures. A PCR screen designed to isolate Hox genes expressed specifically in the posterior part of the body failed to identify any new Hox genes. We conclude that the post-genital segments of Artemia are not defined by any of the genes known to play a role in the specification of posterior segments in other arthropods. We argue that these segments constitute a unique body region that bears no obvious homology to previously characterised domains of Hox gene activity.

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“…With each molt the naupliar hindbody, representing the developing thorax and abdomen-telson, becomes more conspicuous and eventually extends far behind the naupliar head shield. In rhizocephalan nauplii a vestigial abdomen has even been evidenced by expression of a gene typically involved in arthropod segmentation, the transcription factor engrailed , and by morphology (Gibert et al 2000 ;Blin et al 2003 ; see section " Gene expression ").…”

Section: Body Shape and Segmentationmentioning

confidence: 99%

“…A systematic search for engrailed genes revealed duplication events in the cirripedean lineage, independent from the hexapod duplication, and up to three engrailed paralogs were found in the sessile Elminius modestus (Gibert et al 1997 ;Gibert 2002 ). The expression of both engrailed paralogs was followed during larval development of the rhizocephalan Sacculina carcini by immunostaining and in situ hybridisation (Queinnec et al 1999 ;Gibert et al 2000 ;Gibert 2002 ). Surprisingly, in addition to the expected stripes in maxillar and thoracic segments, these data revealed unexpected tiny engrailed expression stripes in a posterior dorsal location in naupliar stages, particularly conspicuous at the nauplius IV stage (Fig.…”

Section: Engrailed Genesmentioning

confidence: 99%