The Complete Mitochondrial Genome of Galba pervia (Gastropoda: Mollusca), an Intermediate Host Snail of Fasciola spp

Abstract

Complete mitochondrial (mt) genomes and the gene rearrangements are increasingly used as molecular markers for investigating phylogenetic relationships. Contributing to the complete mt genomes of Gastropoda, especially Pulmonata, we determined the mt genome of the freshwater snail Galba pervia, which is an important intermediate host for Fasciola spp. in China. The complete mt genome of G. pervia is 13,768 bp in length. Its genome is circular, and consists of 37 genes, including 13 genes for proteins, 2 genes for rRNA, 22 genes for tRNA. The mt gene order of G. pervia showed novel arrangement (tRNA-His, tRNA-Gly and tRNA-Tyr change positions and directions) when compared with mt genomes of Pulmonata species sequenced to date, indicating divergence among different species within the Pulmonata. A total of 3655 amino acids were deduced to encode 13 protein genes. The most frequently used amino acid is Leu (15.05%), followed by Phe (11.24%), Ser (10.76%) and IIe (8.346%). Phylogenetic analyses using the concatenated amino acid sequences of the 13 protein-coding genes, with three different computational algorithms (maximum parsimony, maximum likelihood and Bayesian analysis), all revealed that the families Lymnaeidae and Planorbidae are closely related two snail families, consistent with previous classifications based on morphological and molecular studies. The complete mt genome sequence of G. pervia showed a novel gene arrangement and it represents the first sequenced high quality mt genome of the family Lymnaeidae. These novel mtDNA data provide additional genetic markers for studying the epidemiology, population genetics and phylogeographics of freshwater snails, as well as for understanding interplay between the intermediate snail hosts and the intra-mollusca stages of Fasciola spp..

RETRACTED ARTICLE: The complete mitochondrial genomes of two freshwater snails provide new protein-coding gene rearrangement models and phylogenetic implications

“…Of the 13 PCGs, ten genes were found to initiate with the ATN codon, whereas three started with TTG in both R. swinhoei and P. corneus. These data are in accordance with previous findings from different gastropod clades [2, 4, 9, 14]. Most of PCGs were inferred to use TAA/TAG as stop codons except for T ( P. corneus : cox 1 and cox 2), which frequently occurred in protein-coding genes of most gastropod mt genomes [5, 6, 8, 13].…”

“…1). A high variation in nucleotide composition of pulmonate mt genomes has been reported [2, 4–6, 9, 14]. The variation of overall A + T content ranges from 54.76% ( Ovatella vulcani ) to 77.0% ( Succinea putris ), with an average value of 65.5% (Additional file 1: Table S2).…”

“…PCR products were examined using 1% agarose gel electrophoresis to validate the amplification efficiency and were sequenced using an ABI 377 (Applied Biosystems) automated DNA sequencer using the same primers (one primer at a time) as that for PCR. After de novo assembly and functional annotation, 13 protein-coding genes, rDNA genes, and tRNAs of mt genome were found, and compared with the two known complete mt genome of species of the family Lymnaeidae: Galba pervia (JN564796) [4] and Radix balthica (HQ330989) [14]. The related data were deposited in the National Center for Biotechnology Information (NCBI) Biosample databases with the accession numbers: SRS781941 ( R. swinhoei ) and SRS781939 ( P. corneus ).…”

“…Owing to the unique features such as maternal inheritance, lack of extensive recombination, a relatively high evolutionary rate and abundantly available marker types [6], mitochondrial (mt) genomes have been widely used for species identification, population genetics and evolutionary relationships studies in metazoans including pulmonates [4, 5, 8]. In general, the metazoan mt genome is a single circular DNA molecule of about 14–17 kb in size, typically containing 37 genes [9]: 13 protein-coding genes (PCGs) [cytochrome c oxidase subunits 1–3 ( cox 1- cox 3), apocytochrome b (cyt b ), ATPsynthase subunits 6 and 8 ( atp 6 and atp 8), NADHdehydrogenase subunits 1–6 and 4 L ( nad 1-6 and nad 4L)], two ribosomal RNAs [small and large subunit ribosomal RNA (rrn S and rrn L )] and 22 transfer RNA (tRNA).…”

The complete mitochondrial genome of the golden apple snail Pomacea canaliculata (Gastropoda: Ampullariidae)

“…Overall nucleotide compositions of the light strand in descending order are 40.97% of A, 30.78% of T, 20.48% of C and 12.60% of G. Gene arrangement and distribution are different from the typical vertebrates (Yang et al 2014a(Yang et al , 2016a) and similar to Cipangopaludina cathayensis (Yang et al 2014b). The absence of D-loop is consistent with the Gastropoda (Liu et al 2012;Zeng et al 2015;Zhou et al 2016), but, at least, one lengthy non-coding region is an essential regulatory element for the initiation of transcription and replication (Wolstenholme 1992).…”