Non-concerted evolution in ribosomal ITS2 sequence in Cynoglossus zanzibarensis (Pleuronectiformes: Cynoglossidae)

In this study, we focused on ITS2 in Zanzibar tonguesole, Cynoglossus zanzibarensis (Pleuronectiformes: Cynoglossidae). Three types of ITS2 sequences (Type A, B, and C) coexisted and mainly differ in length, nucleotide diversity (π), secondary structure, and minimum free energy. Based on these different features, Type B and C were speculated as the putative pseudogenic ITS2 region. Moreover, Type C sequences were detected as recombinant from crossing over between Type A and B sequences. To our knowledge, this is the first report on ITS2 recombination in animal ribosomal RNA genes. The high degree of ITS2 sequence polymorphism at the intraindividual level supported a non-concerted evolution pattern in the C. zanzibarensis genome. These results provide useful data for further studies on ITS2 in flatfishes and contribute to polymorphism analyses of ribosomal RNA genes in teleostean fishes.

Source: Biochemical Systematics and Ecology - May 18, 2016 Category: Biochemistry Source Type: research