Mitogenomic analysis of the genus Pseudois: Evidence of adaptive evolution of morphological variation in the ATP synthase genes
Sichuan Key Laboratory of Conservation Biology on Endangered Wildlife, Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, Sichuan 610064, PR China. Mitochondrion
(Impact Factor: 3.25).
07/2012; 12(5):500-5. DOI: 10.1016/j.mito.2012.07.107
The genus Pseudois includes two variable taxa, blue sheep (Pseudois nayaur) and dwarf blue sheep (Pseudois schaeferi), that exhibit notable geographic variation in morphology and ecological niche, suggesting the potential for significant adaptive differentiation between these two goats. Blue sheep are broadly distributed in the Tibetan Plateau and peripheral mountains through Central Asia, while dwarf blue sheep are only found in the gorges of the upper Yangtze River (Jinsha River) near Batang county, Sichuan province and adjacent mountains. Although they are all adapted to high altitude environments, endangered dwarf blue sheep show unique morphological variation and niche shifts compared to blue sheep. Mitochondria play important roles in oxygen usage and energy metabolism. The energetically demanding lifestyles of these high altitude species may have altered the selective regimes on mitochondrial genes encoding proteins related to cellular respiration. Here, we compared the sequences of 13 protein-coding genes in the mitochondrial genome of dwarf blue sheep with those of blue sheep to understand the genetic basis of morphological variation. Using neighbor-joining, maximum-likelihood and Bayesian approaches, we estimated rates of synonymous (d(S)) and nonsynonymous (d(N)) substitutions. Independent analyses showed that no ω ratio was larger than 1, suggesting that all mitochondrial 13 genes were under the purifying selection. Surprisingly, we found that the ω ratio (d(N)/d(S)) of the ATP synthase complex (ATP6 and ATP8) in blue sheep is sixteen times that of dwarf blue sheep (0.340 compared to 0.021). This result was confirmed by a separate analysis of ATP synthase genes from two additional P. schaeferi individuals and two P. nayaur individuals. We hypothesize that the large body size and diverse feeding styles are factors influencing the nonsynonymous substitutions in the ATP synthase complex of blue sheep.
Available from: Feiyun Tu
- "The conservation status of U. aequodonenia, U. andersoni and U. nivatus remains unclear. The mitochondrial protein-coding genes (PCGs) may provide information of the molecular mechanisms of adaptation to highaltitude environments (Luo et al. 2008; Ning et al. 2010; Yu et al. 2011; Peng et al. 2012). Recent studies (Yu et al. 2011; Gu et al. 2012) discovered molecular signatures consistent with adaptive evolution of several mitochondrial genes, such as ND2 and ND6. "
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ABSTRACT: Asiatic shrewlike moles are distributed almost entirely in south-west China; four of the five species of the genus Uropsilus, Uropsilus aequodonenia, U. andersoni, U. investigator and U. soricipes are endemic to China. Excluding the five species, three cryptic species (U. sp. 1, U. sp. 2 and U. sp. 3) and two putative species, U. nivatus and U. atronates, are recognized. The phylogenetic relationships among the species remain unclear and these preclude investigations of their potential adaptations for living in high altitudes. We sequenced the complete mitochondrial DNA genomes of three species of Asiatic shrewlike moles (U. aequodonenia, U. andersoni and U. nivatus). Phylogenetic analyses of 16 published and our de novo mitogenomes yield single, robust trees with the relationships being (U. soricipes (U. sp. 1 (U. nivatus (U. andersoni, U. aequodonenia)))). Further, the tree verifies the validity of recently described U. aequodonenia. Analyses of selection pressure suggest that the 13 mtDNA-encoding genes of species in the genus Uropsilus all have experienced strong purifying selection, although ATP8 accumulated a higher ratio of non-synonymous substitutions than the other loci, which might reflect adaptation of the genus Uropsilus to different environments/elevations.
Available from: Kimberly J Dunham-Snary
- "Alterations in mitochondrial function to promote survival have been documented in numerous species, including the bar-headed goose  and the blue and dwarf blue sheep of Asia . Adaptations in prehistoric humans may have also occurred. "
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ABSTRACT: Obesity is a leading risk factor for a variety of metabolic diseases including cardiovascular disease, diabetes and cancer. Although in its simplest terms, obesity may be thought of as a consequence of excessive caloric intake and sedentary lifestyle, it is also evident that individual propensity for weight gain can vary. The etiology of individual susceptibility to obesity appears to be complex - involving a combination of environmental - genetic interactions. Herein, we suggest that the mitochondrion plays a major role in influencing individual susceptibility to this disease via mitochondrial - nuclear interaction processes, and that environmentally influenced selection events for mitochondrial function that conveyed increased reproductive and survival success during the global establishment of human populations during prehistoric times can influence individual susceptibility to weight gain and obesity.
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ABSTRACT: Abstract The population of blue sheep, Pseudois nayaur, from Helan Mountain in China is considered as a new subspecies. We first determined and annotated its complete mitochondrial genome. The mitogenome is 16,795 bp in length, consisting of 13 protein-coding genes, 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes and a control region. As in other mammals, most mitochondrial genes are encoded on the heavy strand, except for ND6 and eight tRNA genes, which are encoded on the light strand. Its overall base composition is A: 33.2%, T: 26.6%, C: 26.8% and G: 13.3%. The complete mitogenome of the new subspecies of P. nayaur could provide an important data to further explore the taxonomic status of the subspecies.
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