Complete Mitochondrial Genomes Of Pelodiscus Sinensis Wiegtmann And Platysternon Megacephalum Gay

The present thesis includes two parts:Part I: ReviewsIn animals, mtDNA is generally a 15²0 kb circular genome containing 37 genes: 13 protein-coding genes, two rRNA genes, and 22 tRNA genes, as well as a control region. In recent years, mitochondrial DNA (mtDNA) has been widely used as a useful marker system in numerous phylogenetic analyses of vertebrate relationships because of its maternal mode of inheritance and relative lack of recombination. Turtles have highly specialized morphological characteristics, with approximately 270 species in the world. To date, complete mt genomes have been determined for only 18 species, including 17 cryptodiran turtles and a side-necked turtle. Except for Malacochersus tornieri and Platysternon megacephalum, oganizations and gene orders of mitochondrial genomes in the other 16 turtles were identical to that of typical vertebratesPart II: StudiesThe complete mitochondrial genome of Chinese softshell turtle Pelodiscus sinensis was obtained by DNA sequencing based on the PCR fragments of 17 pairs of primers designed on the basis of mtDNA sequences of three related turtle species. The entire genome was 17 364 base pairs in length, with a gene content of 13 protein-coding, two ribosomal RNA and 22 transfer RNA genes, and order identical to that observed in most other vertebrates. Those genes are arranged compactly with no introns and few intergenic nucleotides. The tRNAGln, tRNAAla, tRNAAsn, tRNACys, tRNATyr, tRNASer (CUN), tRNAGlu, tRNAPro and ND6 genes are encoded on the light strand, and the remainder on the heavy strand. The overall base composition was 35.23%A, 27.26%T, 25.73%C, 11.78%G. The sequence was submitted to GenBank under a accession number: NC₀06132. Based on the concatenated sequences of 13 inferred amino acid of protein-coding genes, the...