A Novel Conservation Structure Found in Vertebrate Mitochondrial tRNA￣(phe) Gene

The nucleotide scquence of tRNAphe gene of Carp mitochondria was determined. Sequence comparisons made among Whale,Human,Xenopus laevis, Bovine, Mouse,Chicken and Carp revealed a novel conservative structure in the D. stem (dihydrouridine stem),which is known to vary in other vertebrate mitochondrial and eytoplasmic tRNA genes.This conservative structure contains 13 bp. When the first 7 bp of the conserviative structure were compared with the A domain recognized by RNA Pol III, we noticed partial homology between these two kinds of sequences among different species. In view of the tRNAphe gene's close position to the D loop,it is reasonable to expect extraordinary functions in this novel conservation structure.

Transcriptomic comparison to identify rapidly evolving genes in Braya humilis

The Brassicaceae species Braya humilis shows broad adaptation to different climatic zones and latitudes. However, the molecular adaptation mechanism of B. humilis is poorly understood. In China, B. humilis is mainly distributed on the QinghaiTibetan Plateau(QTP) and in the adjacent arid region. Previous transcriptome analysis of B. humilis has revealed that 39 salt and osmotic stress response genes are subjected to purifying selection during its speciation. To further explore the adaptation mechanism of B. humilis to an arid environment, OrthoMCL program was employed in this study and 6,268 pairs of orthologous gene pairs with high confidence were obtained between B. humilis and Arabidopsis thaliana. A comparative evolutionary analysis based on nonsynonymous to synonymous substitution ratio(Ka/Ks) was then conducted. There were 64 pairs exhibiting a Ka/Ks ratio more than 0.5 and among which, three instrumental candidate genes, T20487,T22576, and T23757, were identified with strong selection signatures(Ka/Ks >1). The corresponding A. thaliana orthologs are double-stranded RNA-binding domain protein, MADS-box family protein, and NADH-dehydrogenase subunit6, which is encoded by mitochondria genome. This report not only demonstrates the adaptation contribution of fast evolving nuclear genes, but also highlights the potential adaptive value of mitochondria gene to the speciation and adaptation of B. humilis toward the extreme environment in an arid region.

Cochlear implants in genetic deafness

Genetic defects are one of the most important etiologies of severe to profound sensorineural hearing loss and play an important role in determining cochlear implantation outcomes.While the pathogenic mutation types of a number of deafness genes have been cloned,the pathogenesis mechanisms and their relationship to the outcomes of cochlear implantation remain a hot research area.The auditory performance is considered to be affected by the etiology of hearing loss and the number of surviving spiral ganglion cells,as well as others.Current research advances in cochlear implantation for hereditary deafness,especially the relationship among clinic-types,genotypes and outcomes of cochlear implantation,will be discussed in this review.

Genetic differentiation of Bemisia tabaci （Gennadius） （Hemiptera： Aleyrodidae） biotype Q based on mitochondrial DNA markers

In the present study, genetic differentiation of Bemisia tabaci （Gennadius） biotype Q was analyzed based on mitochondrial cytochrome oxidase I （mt CO1） gene sequence. The results showed that B. tabaci biotype Q could be separated into two subclades, which were labeled as subclades Q1 and Q2. Subclade Q1 was probably indigenous to the regions around the Mediterranean area and subclade Q2 to Israel or Cyprus. It was because B. tabaci was composed of several genetically distinct groups with a strong geographical association between more closely related biotypes. Not all of the B. tabaci biotype Q in the non-Mediterranean countries come from the same regions. Until now, all B. tabaci biotype Q in China were grouped into subclade Q 1. The B. tabaci biotype Q introduced into the US included both subclades Q 1 and Q2. The genetic structure analysis showed higher genetic variation of subclade Q 1 than that of subclade Q2.

Mitochondrial dysfunction: A hidden trigger of autism?

Autism is a heterogeneous neurodevelopmental and neuropsychiatric disorder with no precise etiology.Deficits in cognitive functions uncover at early stages and are known to have an environmental and genetic basis.Since autism is multifaceted and also linked with other comorbidities associated with various organs,there is a possibility that there may be a fundamental cellular process responsible for this.These reasons place mitochondria at the point of interest as it is involved in multiple cellular processes predominantly involving meta-bolism.Mitochondria encoded genes were taken into consideration lately because it is inher-ited maternally,has its own genome and also functions the time of embryo development.Various researches have linked mitochondrial mishaps like oxidative stress,ROS production and mt-DNA copy number variations to autism.Despite dramatic advances in autism research worldwide,the studies focusing on mitochondrial dysfunction in autism is rather minimal,especially in India.India,owing to its rich diversity,may be able to contribute significantly to autism research.It is vital to urge more studies in this domain as it may help to completely understand the basics of the condition apart from a genetic standpoint.This review focuses on the worldwide and Indian scenario of autism research;mitochondrial abnormalities in autism and possible therapeutic approaches to combat it.