title: Embryonic development and expression analysis of Distal-less in Caprella scaura (Crustacea, Amphipoda, Caprellidea).
abstract: The Caprellidea generally possess rudimentary abdomens and degenerated third and fourth pereopods. Previous molecular phylogenetic studies support the concept that their unique body plan is derived from a gammarid-like body plan from which the abdomen or third and fourth pereopods have been lost in the Caprellidea. To understand the developmental and genetic mechanisms for the morphological evolution of the Caprellidea, we observed the embryonic development of Caprella scaura. Although in the early embryonic stage limb buds appeared in all of the pereonites, we found that elongation of the limb buds did not occur in the third and fourth pereonites; instead, only oval projections (possibly primordial gills) were observed. We next examined the gene expression of Distal-less (Dll) by in situ hybridization and found that Dll was not expressed in the third and fourth pereonites. This suggests that the suppression of Dll expression is responsible for the reduction of Caprellidea pereopods.
authors: Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan.
authors: Atsushi
authors: A
authors: Ito
authors: Masakazu N
authors: MN
authors: Aoki
authors: Kensuke
authors: K
authors: Yahata
authors: Hiroshi
authors: H
authors: Wada
mesh_terms: D000005:Abdomen / Q000196:embryology; D033304:Amphipoda / Q000196:embryology*; D000818:Animals; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D005121:Extremities / Q000196:embryology*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D008853:Microscopy
chemical_list: D004268:DNA-Binding Proteins