A recurrent splice-site mutation in EPHA2 causing congenital posterior nuclear cataract

Intoduction: Inherited cataract, opacification of the lens, is the most common worldwide cause of blindness in children. We aimed to identify the genetic cause of autosomal dominant (AD) posterior nuclear cataract in a four generation British family. METHODS: Whole genome sequence (WGS) was performed on two affected and one unaffected individual of the family and further validated by direct sequencing. Haplotype analysis was performed via genotying. RESULTS: A splice-site mutation c.2826-9G>A in the gene EPHA2, encoding EPH receptor A2 was identified and found to co-segregate with disease. CONCLUSIONS: We have identified a recurrent splice-site mutation c.2826-9G>A in EPHA2 causing isolated posterior nuclear cataract, providing evidence of further phenotypic heterogeneity associated with this variant

Short Term Evolution of a Highly Transmissible Methicillin-Resistant Staphylococcus aureus Clone (ST228) in a Tertiary Care Hospital

Staphylococcus aureus is recognized as one of the major human pathogens and is by far one of the most common nosocomial organisms. The genetic basis for the emergence of highly epidemic strains remains mysterious. Studying the microevolution of the different clones of S. aureus is essential for identifying the forces driving pathogen emergence and spread. The aim of the present study was to determine the genetic changes characterizing a lineage belonging to the South German clone (ST228) that spread over ten years in a tertiary care hospital in Switzerland. For this reason, we compared the whole genome of eight isolates recovered between 2001 and 2008 at the Lausanne hospital. The genetic comparison of these isolates revealed that their genomes are extremely closely related. Yet, a few more important genetic changes, such as the replacement of a plasmid, the loss of large fragments of DNA, or the insertion of transposases, were observed. These transfers of mobile genetic elements shaped the evolution of the ST228 lineage that spread within the Lausanne hospital. Nevertheless, although the strains analyzed differed in their dynamics, we have not been able to link a particular genetic element with spreading success. Finally, the present study showed that new sequencing technologies improve considerably the quality and quantity of information obtained for a single strain; but this information is still difficult to interpret and important investments are required for the technology to become accessible for routine investigations

Sex-specific Trans-regulatory Variation on the Drosophila melanogaster X Chromosome

The X chromosome constitutes a unique genomic environment because it is present in one copy in males, but two copies in females. This simple fact has motivated several theoretical predictions with respect to how standing genetic variation on the X chromosome should differ from the autosomes. Unmasked expression of deleterious mutations in males and a lower census size are expected to reduce variation, while allelic variants with sexually antagonistic effects, and potentially those with a sex-specific effect, could accumulate on the X chromosome and contribute to increased genetic variation. In addition, incomplete dosage compensation of the X chromosome could potentially dampen the male-specific effects of random mutations, and promote the accumulation of X-linked alleles with sexually dimorphic phenotypic effects. Here we test both the amount and the type of genetic variation on the X chromosome within a population of Drosophila melanogaster, by comparing the proportion of X linked and autosomal trans-regulatory SNPs with a sexually concordant and discordant effect on gene expression. We find that the X chromosome is depleted for SNPs with a sexually concordant effect, but hosts comparatively more SNPs with a sexually discordant effect. Interestingly, the contrasting results for SNPs with sexually concordant and discordant effects are driven by SNPs with a larger influence on expression in females than expression in males. Furthermore, the distribution of these SNPs is shifted towards regions where dosage compensation is predicted to be less complete. These results suggest that intrinsic properties of dosage compensation influence either the accumulation of different types of trans-factors and/or their propensity to accumulate mutations. Our findings document a potential mechanistic basis for sex-specific genetic variation, and identify the X as a reservoir for sexually dimorphic phenotypic variation. These results have general implications for X chromosome evolution, as well as the genetic basis of sex-specific evolutionary change

Si+ ion beam mixing of tin layers on crystalline silicon

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Morphology of SiSn multilayered thin films

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Fluence dependence of ion beam induced atomic mixing in the immiscible tin-silicon system

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Ion beam mixing of silicon-tin multilayers

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Further expérience of endoscopy in gynaecology

Les auteurs rapportent 243 cas d'endoscopie pratiqués de 1959. 1972 à la Clinique Obstétricale et Gynécologique de l'Université d'Athènes. Ils soulignent les indications ainsi que l'intérêt particulièrement important des résultats fournis par cette méthode d'exploration

Ion beam mixing of metal-sapphire interfaces

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Phase formation study in α-Al2O3 implanted with niobium ions

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