We produced DNA sequence data from two mitochondrial genes (cytochrome b and the NADH dehydrogenase subunit 2) to reconstruct the phylogenetic relationships among 121 species of the Anseriformes (waterfowls including ducks, geese, swans, the magpie goose and screamers). Phylogenetic analyses converged into a congruent topology and defined several well-supported clades. We calibrated a molecular clock and reconstructed ancestral biogeographical areas using Bayesian inference supporting an austral continental (Gondwanaland) origin of the waterfowls. Ducks, swans and geese might have diversified during the Miocene (23-5 Myr ago) reaching northern distributions in Holarctic and Afrotropical regions. The evolution of hybridization patterns in Anseriformes has been investigated using a cladistic analysis (morphology), which may underestimate or overestimate the phylogenetic divergence among species, or restricted only to ducks. Using a phylogenetic framework, genetic-based distances and a Bayesian time calibration, our data support the hypothesis based on immunological distances of slow rate of appearance of reproductive incompatibilities in waterfowls compared with other vertebrates and the view that these birds may be like frogs in having lost their interspecific hybridization potential more slowly than mammals.
Opa1 participates in inner mitochondrial membrane fusion and cristae morphogenesis. Here, we show that muscle-specific Opa1 ablation causes reduced muscle fiber size, dysfunctional mitochondria, enhanced Fgf21, and muscle inflammation characterized by NF-κB activation, and enhanced expression of pro-inflammatory genes. Chronic sodium salicylate treatment ameliorated muscle alterations and reduced the muscle expression of Fgf21. Muscle inflammation was an early event during the progression of the disease and occurred before macrophage infiltration, indicating that it is a primary response to Opa1 deficiency. Moreover, Opa1 repression in muscle cells also resulted in NF-κB activation and inflammation in the absence of necrosis and/or apoptosis, thereby revealing that the activation is a cell-autonomous process and independent of cell death. The effects of Opa1 deficiency on the expression NF-κB target genes and inflammation were absent upon mitochondrial DNA depletion. Under Opa1 deficiency, blockage or repression of TLR9 prevented NF-κB activation and inflammation. Taken together, our results reveal that Opa1 deficiency in muscle causes initial mitochondrial alterations that lead to TLR9 activation, and inflammation, which contributes to enhanced Fgf21 expression and to growth impairment.
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The insular endemic Cyprus Wheatear Oenanthe cypriaca has been considered as a subspecies of Pied Wheatear O. pleschanka. However, due to several differences in behaviour, habitat selection and morphology, it is currently treated by most authors as an independent species. Here, we used mitochondrial nucleotide sequences of the cytochrome oxidase subunit 1 gene (679 base pairs), playback experiments and dummy presentations to assess the status of O. cypriaca. For the playback experiments we used the conspecific song, and heterospecific songs of the two subspecies of Black-eared Wheatear O. hispanica hispanica and O. hispanica melanoleuca, O. pleschanka, and Finsch's Wheatear O. finschii. Experimental dummy presentations included O. cypriaca, O. pleschanka and a dark and light morph of O. h. melanoleuca. O. cypriaca responded significantly stronger towards the conspecific model and towards conspecific playbacks than towards heterospecific stimuli. ML and BI analyses support the close relationship between O. cypriaca, O. pleschanka and O. h. melanoleuca. With a relative high posterior probability value (0.98), O. cypriaca clusters closer to O. h. melanoleuca from Iran and Israel (on migration) and O. pleschanka from Iran than to O. pleschanka obtained from Kazakhstan, Russia, Mongolia and wintering areas in East Africa (Kenya). The scenario suggests that O. cypriaca might be either a relatively young taxon, which is yet behavioural distinct, but genetically still similar to its sister populations on the mainland. Alternatively, we may assume a close relationship as an indication for potential ongoing hybridisation processes involving all three forms.
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