Different Patterns of Evolution in the Centromeric and Telomeric Regions of Group A and B Haplotypes of the Human Killer Cell Ig-Like Receptor Locus

The fast evolving human KIR gene family encodes variable lymphocyte receptors specific for polymorphic HLA class I determinants. Nucleotide sequences for 24 representative human KIR haplotypes were determined. With three previously defined haplotypes, this gave a set of 12 group A and 15 group B haplotypes for assessment of KIR variation. The seven gene-content haplotypes are all combinations of four centromeric and two telomeric motifs. 2DL5, 2DS5 and 2DS3 can be present in centromeric and telomeric locations. With one exception, haplotypes having identical gene content differed in their combinations of KIR alleles. Sequence diversity varied between haplotype groups and between centromeric and telomeric halves of the KIR locus. The most variable A haplotype genes are in the telomeric half, whereas the most variable genes characterizing B haplotypes are in the centromeric half. Of the highly polymorphic genes, only the 3DL3 framework gene exhibits a similar diversity when carried by A and B haplotypes. Phylogenetic analysis and divergence time estimates, point to the centromeric gene-content motifs that distinguish A and B haplotypes having emerged ∼6 million years ago, contemporaneously with the separation of human and chimpanzee ancestors. In contrast, the telomeric motifs that distinguish A and B haplotypes emerged more recently, ∼1.7 million years ago, before the emergence of Homo sapiens. Thus the centromeric and telomeric motifs that typify A and B haplotypes have likely been present throughout human evolution. The results suggest the common ancestor of A and B haplotypes combined a B-like centromeric region with an A-like telomeric region

An extensive performance evaluation of full-reference HDR image quality metrics

International audienceHigh dynamic range (HDR) image and video technology has recently attracted a great deal of attention in the multimedia community, as a mean to produce truly realistic video and further improve the quality of experience (QoE) of emerging multimedia services. In this context, measuring the quality of compressed HDR content plays a fundamental role. However, full-reference (FR) HDR visual quality assessment poses new challenges with respect to the conventional low dynamic range case. Quality metrics have to be redesigned or adapted to HDR, and understanding their reliability to predict users’ judgments is even more critical due to the still limited availability of HDR displays to perform subjective evaluations. The goal of this paper is to provide a complete and thorough survey of the performance of the most popular HDR FR image quality metrics. To this end, we gather several existing HDR image databases with subjective quality annotations, in addition to a new one created by ourselves. After aligning the scores in these databases, we obtain an extensive set of 690 compressed HDR images, along with their subjective quality. Next, we analyze in depth many FR metrics, including those used in MPEG standardization, using both classical correlation analyses and classification accuracy. We believe that our results could serve as the most complete and comprehensive benchmark of image quality metrics in the field of HDR image compression