185 resultados para Mitochondrial Dysfunction


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In spite of several classification attempts among taxa of the genus Lepus, phylogenetic relationships still remain poorly understood. Here, we present molecular genetic evidence that may resolve some of the current incongruities in the phylogeny of the leporids. The complete mitochondrial cytb, 12S genes, and parts of ND4 and control region fragments were sequenced to examine phylogenetic relationships among Chinese hare taxa and other leporids throughout the World using maximum parsimony, maximum likelihood, and Bayesian phylogenetic reconstruction approaches. Using reconstructed phylogenies, we observed that the Chinese hare is not a single monophyletic group as originally thought. Instead, the data infers that the genus Lepus is monophyletic with three unique species groups: North American, Eurasian, and African. Ancestral area analysis indicated that ancestral Lepus arose in North America and then dispersed into Eurasia via the Bering Land Bridge eventually extending to Africa. Brooks Parsimony analysis showed that dispersal events followed by subsequent speciation have occurred in other geographic areas as well and resulted in the rapid radiation and speciation of Lepus. A Bayesian relaxed molecular clock approach based on the continuous autocorrelation of evolutionary rates along branches estimated the divergence time between the three major groups within Lepus. The genus appears to have arisen approximately 10.76 MYA (+/- 0.86 MYA), with most speciation events occurring during the Pliocene epoch (5.65 +/- 1.15 MYA similar to 1.12 +/- 10.47 MYA). (c) 2005 Elsevier Inc. All rights reserved.

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To study the phylogenetic relationships of the macaques, five gene fragments were sequenced from 40 individuals of eight species: Macaca mulatta, M. cyclopis, M. fascicularis, M. arctoides, M. assamensis, M. thibetana, M. silenus, and M. leonina. In addition, sequences of M. sylvanus were obtained from Genbank. A baboon was used as the outgroup. The phylogenetic trees were constructed using maximum-parsimony and Bayesian methods. Because five gene fragments were from the mitochondrial genome and were inherited as a single entity without recombination, we combined the five genes into a single analysis. The parsimony bootstrap proportions we obtained were higher than those from earlier studies based on the combined mtDNA dataset. Excluding M. arctoides, our results are generally consistent with the classification of Delson (1980). Our phylogenetic analyses agree with earlier studies suggesting that the mitochondrial lineages of M. arctoides share a close evolutionary relationship with the mitochondrial lineages of the fascicularis group of macaques (and M. fascicularis, specifically). M. mulatta (with respect to M. cyclopis), M. assamensis assamensis (with respect to M. thibetana), and M. leonina (with respect to M. silenus) are paraphyletic based on our analysis of mitochondrial genes.

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An up-to-date view of the worldwide mitochondrial DNA (mtDNA) phylogeny together with an evaluation of the conservation of each site is a reliable tool for detecting errors in mtDNA studies and assessing the functional importance of alleged pathogenic mutations. However, most of the published studies on mitochondrial diseases make very little use of the phylogenetic knowledge that is currently available. This drawback has two inadvertent consequences: first, there is no sufficient a posteriori quality assessment of complete mtDNA sequencing efforts; and second, no feedback is provided for the general mtDNA database when apparently new mtDNA lineages are discovered. We demonstrate, by way of example, these issues by reanalysing three mtDNA sequencing attempts, two from Europe and another one from East Asia. To further validate our phylogenetic deductions, we completely sequenced two mtDNAs from healthy subjects that nearly match the mtDNAs of two patients, whose sequences gave problematic results. (c) 2005 Elsevier Inc. All rights reserved.

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More than 10 species within the freshwater fish genus Sinoncyclocbeilus adapt to caves and show different degrees of degeneration of eyes and pigmentation. Therefore, this genus can be useful for studying evolutionary developmental mechanisms, role of natural selection and adaptation in cave animals. To better understand these processes, it is indispensable to have background knowledge about phylogenetic relationships of surface and cave species within this genus. To investigate phylogenetic relationships among species within this genus, we determined nucleotide sequences of complete mitochondrial cytochrome b gene (1140 bp) and partial ND4 gene (1032 bp) of 31 recognized ingroup species and one outgroup species Barbodes laticeps. Phylogenetic trees were reconstructed using maximum parsimony. Bayesian, and maximum likelihood analyses. Our phylogenetic results showed that all species except for two surface species S. jii and S. macrolepis clustered as five major monophyletic clades (I, II, III, IV, and V) with strong supports. S. jii was the most basal species in all analyses, but the position of S. macrolepis was not resolved. The cave species were polyphyletic and occurred in these five major clades. Our results indicate that adaptation to cave environments has occurred multiple times during the evolutionary history of Sinocyclocheilus. The branching orders among the clades I, II, III, and IV were not resolved, and this might be due to early rapid radiation in Sinocyclocheilus. All species distributed in Yunnan except for S. rhinocerous and S. hyalinus formed a strongly supported monophyletic group (clade V), probably reflecting their common origins. This result suggested that the diversification of Sinocyclocheilus in Yunnan may correlate with the uplifting of Yunnan Plateau. © 2005 Published by Elsevier Inc.

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Researchers are still discussing the classification of Nycticebus. We established a molecular phylogeny covering all recognized taxa in Nycticebus to provide information for further evaluation. We sequenced partial D-loop (ca. 390 bp) and cytochrome b gen

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Regardless of the well-documented virilis species group, most groups of the Drosophila virilis section have not been completely studied at molecular level since it was suggested. Therefore, phylogenetic relationships among and within species groups of the

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To obtain a more complete understanding of the evolutionary history of the leaf-eating monkeys we have examined the mitochondrial genome sequence of two African and six Asian colobines. Although taxonomists have proposed grouping the "odd-nosed" colobines

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Fringillidae is a large and diverse family of Passeriformes. So far, however, Fringillidae relationships deduced from morphological features and by a number of molecular approaches have remained unproven. Recently, much attention has been attracted to mitochondrial tRNA genes, whose sequence and secondary structural characteristics have shown to be useful for Acrodont Lizards and deep-branch phylogenetic studies. In order to identify useful phylogenetic markers and test Fringillidae relationships, we have sequenced three major clusters of mitochondrial tRNA genes from 15 Fringillidae, taxa. A coincident tree, with coturnix as outgroup, was obtained through Maximum-likelihood method using combined dataset of 11 mitochondrial tRNA gene sequences. The result was similar to that through Neighbor-joining but different from Maximum-parsimony methods. Phylogenetic trees constructed with stem-region sequences of 11 genes had many different topologies and lower confidence than with total sequences. On the other hand, some secondary structural characteristics may provide phylogenetic information on relatively short internal branches at under-genus level. In summary, our data indicate that mitochondrial tRNA genes can achieve high confidence on Fringillidae phylogeny at subfamily level, and stem-region sequences may be suitable only at above-family level. Secondary structural characteristics may also be useful to resolve phylogenetic relationship between different genera of Fringillidae with good performance.

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Background: Previously reported evidence indicates that pigs were independently domesticated in multiple places throughout the world. However, a detailed picture of the origin and dispersal of domestic pigs in East Asia has not yet been reported. Results:

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Background: Despite the small number of ursid species, bear phylogeny has long been a focus of study due to their conservation value, as all bear genera have been classified as endangered at either the species or subspecies level. The Ursidae family repre

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Bengal slow lorises (Nycticebus bengalensis) and pygmy slow lorises (Nycticebus pygmaeus) are nocturnal which creates difficulties to study them in the field. There is a scarcity of data on them and their population genetics are poorly understood. We sequ

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The complete mitochondrial genomes of the primary cancerous, matched paracancerous normal and distant normal tissues from 10 early-stage breast cancer patients were analyzed in this study, with special attempt (i) to investigate whether the reported high

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Phylogenetic relationships among representative species of the subfamily Raninae were investigated using approximately 2000 base pairs of DNA sequences from two mitochondrial (12S rRNA, 16S rRNA) and two nuclear (tyrosinase, rhodopsin) genes. Phylogenetic

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Based on partial sequences of the 12S and 16S ribosomal RNA genes, we estimated phylogenetic relationships among brown frogs of the Rana temporaria group from China. From the phylogenetic trees obtained, we propose to include Rana zhengi in the brown frog