Project description:While the vertebrate body plan is highly conserved amongst all species of this taxon, extreme variations thereof can be documented in snakes, which display both an absence of limbs and an unusually elongated trunk. As Hox genes are strong candidates both for the making and the evolution of this body plan, their comparative study in such a morphologically diverged group is informative regarding their potential causative importance in these processes. In this work we use an interspecies comparative approach where different aspects of regulation at the HoxD locus are investigated. We find that although spatial collinearity and associated epigenetic mark dynamics are conserved in the corn snake, other regulatory modalities have been largely restructured. A BAC transgenic approach indeed revealed that, while the majority of mesodermal enhancers in vertebrates appear to be mostly located outside of the cluster, the corn snake contains most mesodermal trunk enhancers within the HoxD cluster. We also find that, despite the absence of limbs and an altered Hoxd gene regulation in external genitalia, the bimodal chromatin structure at the corn snake HoxD locus is maintained. The analysis of particular enhancer sequences initially defined in the mouse and further isolated at the snake orthologous locus showed differences in their specificities for the limb and genital bud expression. Of particular interest, a snake counterpart of a mouse limb-only enhancer sequence evolved into a genital-only enhancer. Such a regulatory exaptation suggests that enhancer versatility may have been an important factor to accompany the transition towards the snake body plan. These results show that vertebrate morphological evolution is likely to have been associated with extensive reorganization at the HoxD regulatory landscapes while respecting a very conserved general regulatory framework.
2016-11-05 | GSE79047 | GEO
Project description:Blue coral bacterial microbiome through time
Project description:The Malaysian Node of the Human Variome Project Database (MyHVPDb) is a country specific database of human variant and gene mutation that was established in 2011. This ethnic specific mutation and variation databases are being continuously updated, recording extensive information over the genetic heterogeneity of the Malaysian ethnic groups. The database comprises of SNP Database and Mutation Database. The SNP database has stored 291718 SNPs that was obtained by genotyping the SNPs of 101 healthy individuals from six Malay sub-ethnic groups which consist of Malay Kelantan, Malay Banjar, Malay Kedah, Malay Jawa, Malay Bugis and Malay Champa.
Project description:Comparative-genomic studies have reported widespread variation in levels of gene expression within and between species. In the vast majority of cases, the phenotypic and evolutionary relevance of regulatory change is unknown. We haveu sed a wild Malaysian population of S. cerevisiae as a testbed in the search to identify organismal correlates of regulatory variation. Malaysian yeast, when cultured in standard medium, activated regulatory programs that protect cells from the toxic effects of high iron. Analysis of differential gene expression between three Malaysian and two Wine/European isolates and allele-specific expression within three Malaysian x Wine/European hybrids.