title: Evolutionary dynamics of rDNA clusters in chromosomes of five clam species belonging to the family Veneridae (Mollusca, Bivalvia).
abstract: The chromosomal changes accompanying bivalve evolution are an area about which few reports have been published. To improve our understanding on chromosome evolution in Veneridae, ribosomal RNA gene clusters were mapped by fluorescent in situ hybridization (FISH) to chromosomes of five species of venerid clams (Venerupis corrugata, Ruditapes philippinarum, Ruditapes decussatus, Dosinia exoleta, and Venus verrucosa). The results were anchored to the most comprehensive molecular phylogenetic tree currently available for Veneridae. While a single major rDNA cluster was found in each of the five species, the number of 5S rDNA clusters showed high interspecies variation. Major rDNA was either subterminal to the short arms or intercalary to the long arms of metacentric or submetacentric chromosomes, whereas minor rDNA signals showed higher variability. Major and minor rDNAs map to different chromosome pairs in all species, but in R. decussatus one of the minor rDNA gene clusters and the major rDNA cluster were located in the same position on a single chromosome pair. This interspersion of both sequences was confirmed by fiber FISH. Telomeric signals appeared at both ends of every chromosome in all species. FISH mapping data are discussed in relation to the molecular phylogenetic trees currently available for Veneridae.
authors: Departamento de Bioquímica Xenética e Inmunoloxía, Universidade de Vigo, 36310 Vigo, Spain ; Department of Biogeochemistry and Ecotoxicology, Laboratory of Ecotoxicology, rue de l'Ile d'Yeu, BP 21105, 44311 Nantes Cedex 03, France.
authors: Concepción
authors: C
authors: Pérez-García
authors: Departamento de Bioquímica Xenética e Inmunoloxía, Universidade de Vigo, 36310 Vigo, Spain.
authors: Ninoska S
authors: NS
authors: Hurtado
authors: Departamento de Bioquímica Xenética e Inmunoloxía, Universidade de Vigo, 36310 Vigo, Spain.
authors: Paloma
authors: P
authors: Morán
authors: Departamento de Bioquímica Xenética e Inmunoloxía, Universidade de Vigo, 36310 Vigo, Spain.
authors: Juan J
authors: JJ
authors: Pasantes
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000235:genetics*; D002875:Chromosomes / Q000235:genetics*; D004275:DNA, Ribosomal / Q000235:genetics*; D019143:Evolution, Molecular; D010802:Phylogeny; D012341:RNA, Ribosomal, 5S / Q000235:genetics*; D013045:Species Specificity
chemical_list: D004275:DNA, Ribosomal; D012341:RNA, Ribosomal, 5S