Design and test results of the calibration unit for the MOAO demonstrator RAVEN

INO has designed, assembled and tested the Raven Multi-Object Adaptive Optics demonstrator calibration unit. This sub-system consists in a telescope simulator that will allow aligning Raven's components during its integration, testing its Adaptive Optics performances in the laboratory and at the telescope, and calibrating the Adaptive Optics system by building the interaction matrix and measuring the non-common path aberrations. The system is presented with the challenges that needed to be overcome during the design and integration phases. The system test results are also presented and compared to the model predictions.Peer reviewed: YesNRC publication: Ye

Evolution of orthologous tandemly arrayed gene clusters

<p>Abstract</p> <p>Background</p> <p>Tandemly Arrayed Gene (TAG) clusters are groups of paralogous genes that are found adjacent on a chromosome. TAGs represent an important repertoire of genes in eukaryotes. In addition to tandem duplication events, TAG clusters are affected during their evolution by other mechanisms, such as inversion and deletion events, that affect the order and orientation of genes. The DILTAG algorithm developed in <abbrgrp><abbr bid="B1">1</abbr></abbrgrp> makes it possible to infer a set of optimal evolutionary histories explaining the evolution of a single TAG cluster, from an ancestral single gene, through tandem duplications (simple or multiple, direct or inverted), deletions and inversion events.</p> <p>Results</p> <p>We present a general methodology, which is an extension of DILTAG, for the study of the evolutionary history of a set of orthologous TAG clusters in multiple species. In addition to the speciation events reflected by the phylogenetic tree of the considered species, the evolutionary events that are taken into account are simple or multiple tandem duplications, direct or inverted, simple or multiple deletions, and inversions. We analysed the performance of our algorithm on simulated data sets and we applied it to the protocadherin gene clusters of human, chimpanzee, mouse and rat.</p> <p>Conclusions</p> <p>Our results obtained on simulated data sets showed a good performance in inferring the total number and size distribution of duplication events. A limitation of the algorithm is however in dealing with multiple gene deletions, as the algorithm is highly exponential in this case, and becomes quickly intractable.</p