Mitochondrial Dna最新文献

Brachymystax lenok tsinlingensis is an endangered freshwater fish and distributed in mountains steams of Qinling Mountains, China. In this study, a comparative study of the mtDNA control region (D-loop) was performed to analyze its natural population structure and the genetic diversity of 53 individuals from four locations (TB, YX, LX and ZZ populations). Sequence analysis revealed three different domains and two feature sequences of the control region. The estimated haplotype and nucleotide diversity were 9 and 0.0023, respectively. Genetic structure analysis showed a high-level genetic diversity of B. lenok tisnlingensis (h = 0.6060 ± 0.1499). The AMOVA analysis indicated that 26.02% of total variation came from individual populations, and 73.98% from variation within the four geographic populations, which showed low genetic differentiation between the four geographic groups. Test of neutral evolution and mismatch distribution indicated that no historical expansion occurred in these populations. The high genetic diversity and low genetic differentiation would provide new information for conservation and exploitation of this species.

The presence of Hyalinobatrachium orientale in Tobago and in northeastern Venezuela is puzzling as this species is unknown from the island of Trinidad, an island often hypothesized to be a stepping-stone for the mainland fauna to colonize Tobago. A period of extended isolation on Tobago could result in the Hyalinobatrachium population becoming distinct from the mainland H. orientale. Here, we use 12S and 16S rDNA gene fragments from nine H. orientale specimens from Tobago and the mainland to assess their relationship and taxonomy, as well as the tempo and mode of speciation. The results suggest H. orientale from Venezuela and Tobago are monophyletic and the two populations diverged about 3 million years ago. This estimate corresponds with the drier climate and lower sea levels of the Pliocene glaciation periods. We hypothesize that lower sea levels resulted in land-bridge formations connecting the mainland and Tobago, with a corridor of habitat allowing H. orientale to colonize Tobago to the west of Trinidad.

In this study, the total mitochondrial genome sequence of Pseudobagrus ondon Shaw was firstly sequenced and determined. The total genome is 16,543 bp in length. It consists of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and 2 non-coding regions. These results provide useful data to the natural resources conservation and systematics analysis of P. ondon Shaw.

Prevalence estimations for mitochondrial disorders still vary widely and only few epidemiologic studies have been carried out so far. With the present work we aim to give a comprehensive overview about frequencies of the most common mitochondrial mutations in Hungarian patients. A total of 1328 patients were tested between 1999 and 2012. Among them, 882 were screened for the m.3243A > G, m.8344A > G, m.8993T > C/G mutations and deletions, 446 for LHON primary mutations. The mutation frequency in our cohort was 2.61% for the m.3243A > G, 1.47% for the m.8344A > G, 17.94% for Leber's Hereditary Optic Neuropathy (m.3460G > A, m.11778G > A, m.14484T > C) and 0.45% for the m.8993T > C/G substitutions. Single mtDNA deletions were detected in 14.97%, while multiple deletions in 6.01% of the cases. The mutation frequency in Hungarian patients suggestive of mitochondrial disease was similar to other Caucasian populations. Further retrospective studies of different populations are needed in order to accurately assess the importance of mitochondrial diseases and manage these patients.

The mitochondrial DNA (mtDNA) typing is useful for the species determination of degraded samples and the nucleotide diversity of target fragments across species is crucial for the discrimination. In this study, the short and highly polymorphic regions flanked by two conserved termini were sought by the sequence alignment of mtDNA across species and two target regions located at 12S rRNA gene were characterized. Two universal primer sets were developed that appear to be effective for a wide variety of mammalian species, even for domestic birds. The two target regions could be efficiently amplified using their universal primer sets on degraded samples and provide sufficient information for species determination. Therefore, the two short and highly variable target regions might provide a high discriminative capacity and should be suitable for the species determination of degraded samples.

Passalurus ambiguus is a common pinworm which parasitizes in the caecum and colon of rabbits. This study examined genetic variability among P. ambiguus isolated from naturally infected rabbits in four different provinces in China. The partial mitochondrial (mt) cytochrome c oxidase subunit 1 (pcox1), cytochrome b (pcytb) and NADH dehydrogenase subunits 1 and 5 (pnad1 and pnad5) were amplified separately from individual nematodes by PCR and sequenced. The results showed that pcox1, pcytb, pnad1 and pnad5 were 714, 663, 645 and 546 bp in length, respectively. The intra-specific sequence variations within P. ambiguus were 0-1.1% for pcox1, 0-1.2% for pcytb, 0-0.6% for pnad1 and 0-1.3% for pnad5, whereas inter-specific sequence differences with other members of the Oxyuridae were 16.2-17.3% for pcox1, 27.8-30.4% for pcytb, 20.2-24.0% for pnad1 and 27.1-30.3% for pnad5. Phylogenetic analyses using Bayesian inference (BI), maximum likelihood (ML) and maximum parsimony (MP) methods, based on the combined sequences of the four partial mtDNA sequences, revealed that all the P. ambiguus samples form monophyletic groups. This study demonstrated the existence of low-level intra-specific variation in cox1, cytb, nad1 and nad5 genes among P. ambiguus isolates from different geographic regions in China, and these four mtDNA sequences can be used as genetic markers for the population genetic studies of P. ambiguus, as well as the differentiation of P. ambiguus from other oxyurid nematodes.

The genetic diversity of the three major artificially propagated populations of Chinese sucker, an endangered freshwater fish species, was investigated using the sequences of mitochondrial DNA (mtDNA) control regions. Among the 89 individuals tested, 66 variable sites (7.26%) and 10 haplotypes were detected (Haplotype diversity Hd = 0.805, Nucleotide diversity π = 0.0287). In general, genetic diversity was lower in artificially propagated populations than in wild populations. This reduction in genetic diversity may be due to population bottlenecks, genetic drift and human selection. A stepping-stone pattern of gene flow was detected in the populations studied, showing much higher gene flow between neighbouring populations. To increase the genetic diversity, wild lineages should be introduced, and more lineages should be shared among artificially propagated populations.

Swimming crab Ovalipes punctatus is a commercially important species in the East China Sea and Yellow Sea, but there is limited knowledge of its genetic population structure. The population genetic structure of O. punctatus in East China Sea and Yellow Sea was examined with a 658-bp segment of the mtDNA COI gene. A total of 60 individuals were collected from five locations and 48 haplotypes were obtained. Mean haplotype diversity and nucleotide diversity for the five populations were 0.9876 ± 0.0068 and 0.0074 ± 0.0041, respectively. Analysis of molecular variance (AMOVA) detected no significant differences at all hierarchical levels, and all FST values were non-significant, indicating that no significant population genetic structure exists in the East China Sea and Yellow Sea. These results supported the null hypothesis that O. punctatus within the East China Sea and Yellow Sea constitutes a panmictic mtDNA gene pool. Neutrality tests and mismatch distribution supported population expansion in this species, indicating that climate change could play an important role in affecting the demographic history of marine species. Strong dispersal capacity of larvae and adults, and ocean currents in the studied area could be the reasons for genetic homogeneity in this species in the East China Sea and Yellow Sea. Another explanation for the lack of phylogeographic structure in O. punctatus might reflect a recent range expansion after the last glacial maximum and insufficient time to attain migration-drift equilibrium.

In this study, the complete mitochondrial genome sequence of the Shaziling pig was reported in Human Province, which was determined through PCR-based method. The total length of the mitogenome is 16,690 bp. It contains the typical structure, including 2 ribosomal RNA genes, 13 protein-coding genes, 22 transfer RNA genes and 1 non-coding control region (D-loop region) as that of most other vertebrates. The overall composition of the mitogenome was estimated to be 34.67% for A, 25.84% for T, 26.17% for C and 13.32% for G, with an A + T (60.51%)-rich feature in the Shaziling pig. All the protein initiation codons are ATG, except for ND2, ND3 and ND5 are ATA, ND4L is GTG, ND6 is TTA. The complete mitochondrial genome sequence of the Shaziling pig in Human Province provides an important data set for the study in genetic mechanism.

Until now the complete mitochondrial genome (mitogenome) sequences of only three species of clitellate have been available. We have determined the complete mitogenome sequences of the elusive Burmese giant earthworm Tonoscolex birmanicus (Clitellata: Megascolecidae), which is endemic to Myanmar. The 15,170-bp long genome contains the 37 genes typical of metazoan mitogenomes [13 protein-coding genes (PCG), 2 rRNA genes and 22 tRNA genes] and 1 major non-coding region. All of the 37 genes are transcribed from the same DNA strand. The arrangement of the T. birmanicus mitogenome is identical to that of two within-ordinal species Lumbricus terrestris and Perionyx excavates. All 13 PCGs start with the ATG. For the stop codon, only six PCGs end with the TAA, whereas the remaining ones ends with the incomplete stop codon, T. Genes overlap in a total of 14 bp in five locations, and harbor a total of 16 bp of intergenic spacer sequences in nine locations.