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Barnacle duplicate engrailed genes: divergent expression patterns and evidence for a vestigial abdomen
Author(s) -
Gibert JeanMichel,
MouchelVielh Emmanuèle,
Quéinnec Eric,
Deutsch Jean S.
Publication year - 2000
Publication title -
evolution and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.651
H-Index - 78
eISSN - 1525-142X
pISSN - 1520-541X
DOI - 10.1046/j.1525-142x.2000.00059.x
Subject(s) - engrailed , biology , appendage , barnacle , body plan , crustacean , telson , anatomy , gene , epidermis (zoology) , evolutionary biology , genetics , gene expression , zoology , decapoda , homeobox
SUMMARY Cirripedes (barnacles) are crustaceans that are characterized by a very peculiar body plan, in particular by the lack of an abdomen. To study their body plan, we searched for their engrailed gene. We found two engrailed ( en.a/en.b ) genes in cirripedes. The two engrailed genes of the rhizocephalan barnacle Sacculina carcini are expressed in the posterior compartment of developing segments and appendages. When the neuroectoderm differentiates into epidermis and neuroderm the expression patterns of en.a and en.b diverge dramatically. en.a expression fades in segment epidermis whereas it is subsequently detected ventrally in reiterated putative neural cells. At the same time, en.b expression increases in the epidermis, which makes it a very good segmentation marker. Five tiny en.b stripes are observed between the sixth thoracic segment and the telson. We interpret these stripes as the molecular definition of vestigial abdominal segments, being the remnant of an ancestral state in keeping with the bodyplan of maxillopod crustaceans. engrailed expression is the first molecular evidence for a segmented abdomen in barnacles.