Two different and functional nuclear rDNA genes in the abalone Haliotis tuberculata: tissue differential expression

• Published in: Genetica Vol. 139; no. 10; pp. 1217 - 1227
• Main Authors: Van Wormhoudt, Alain, Gaume, Béatrice, Le Bras, Yvan, Roussel, Valérie, Huchette, Sylvain
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer-Verlag 01.10.2011; Springer Netherlands; Springer Nature B.V; Springer Verlag
• Subjects: abalone; Agricultural sciences; Agronomy; Animal Genetics and Genomics; Animals; Base Sequence; Biodiversity and Ecology; Biomedical and Life Sciences; Cell Nucleus - genetics; Conserved Sequence; Digestive glands; DNA, Ribosomal - genetics; Environmental Sciences; Evolutionary Biology; Gastropoda - cytology; Gastropoda - genetics; gene expression regulation; genes; Genetics; gills; Gonads; Haliotis; Haliotis tuberculata; Human Genetics; internal transcribed spacers; Life Sciences; Microbial Genetics and Genomics; Molecular Sequence Data; Organ Specificity; phylogeny; Plant Genetics and Genomics; ribosomal DNA; RNA, Ribosomal - genetics; Transcriptome; Abalone; Differential expression; Haliotis; Two different rDNA genes
• ISSN: 0016-6707; 1573-6857
• DOI: 10.1007/s10709-011-9623-8

Analysis of the 18S rDNA sequences of Haliotis tuberculata tuberculata and H. t. coccinea subtaxa identified two different types of 18S rDNA genes and ITS1 regions. These two different genes were also detected in H. marmorata, H. rugosa and H. diversicolor that are separated from H. tuberculata by 5–65 mya. The mean divergence value between type I and type II sequences ranged from 7.25% for 18S to 80% for ITS1. ITS1 type II is homologous with the ITS1 consensus sequences published for many abalone species, whereas ITS1 type I presented only minor homology with a unique database entry for H. iris ITS1. A phylogenetic analysis makes a clear separation between type I and type II ITS1 sequences and supports grouping H. t. tuberculata, H. t. coccinea and H. marmorata together. The two subtaxa do not show any significant differences between the homologous 18S rDNA sequences. A general structure of the ITS1 transcript was proposed, with four major helices for the two types. The two genes were expressed and, for the first time, a putative differential expression of ITS1 type I was detected in the gills, digestive gland and gonads whereas ITS1 type II was expressed in all tissues.