Project description:The Danioninae subfamily of teleost fishes boasts up to four hundred distinct species that have evolved to display a stunning diversity of morphological forms. Here we use newly assembled genome sequences of four laboratory and wild zebrafish strains as well as eleven species of the Danio and Danionella genera to explore their phylogenetic history and the genetic basis of pigment pattern diversification. Phylogenomic analyses uncover extensive introgression and incomplete lineage sorting that have obscured phylogenetic relationships within Danio and corroborate an ancient hybrid origin of zebrafish. Whereas D. rerio inherited ancestral horizontal stripes, relatives repeatedly evolved spots and vertical bars. Interspecific complementation tests reveal functional divergence of the adhesion molecule gene igsf11 and the gap junction gene gja5b between the striped zebrafish and Danio species with divergent patterns. Comparative genomic and transcriptomic analyses suggest that protein and regulatory evolution have accompanied pigment pattern diversification. Our analyses elucidate complex genetic changes underlying the phylogenetic history and morphological diversification in the Danio genus. Resolved phylogenetic relationships, available genome assemblies, transcriptomes, and genetic tractability establish Danio fish species as excellent models for biomedical research in vertebrates.
Project description:Leaf shape is a spectacularly diverse trait that influences various aspects of plant physiology, and is even correlated with crop yield and quality in multiple species. However, only a few genetic dissections of leaf shape have been accomplished at a species-wide level. Here, we perform an initial characterization of leaf shape variation in Ipomoea batatas, the sweetpotato, at multiple scales of analysis. We use a transcriptomic survey to identify gene expression changes associated with two commonly studied leaf shape traits--circularity and aspect ratio using 19 individuals (accession) of sweetpotato. We comprehensively describe the remarkable morphological diversity in leaf shape in sweetpotato, and identify 147 differentially regulated genes associated with circularity and aspect ratio, providing an initial set of hypotheses regarding the genetic basis of leaf shape in this species.
Project description:Species within the Drosophila quinaria group are models for ecological genetic studies on topics that include morphological diversity, color pattern development, and feeding behavior. Here, we performed bulk RNA-seq of mixed male and female adult flies to provide evidence for annotation of our hybrid assembly of the Drosophila subpalustris genome.
Project description:Species within the Drosophila quinaria group are models for ecological genetic studies on topics that include morphological diversity, color pattern development, and feeding behavior. Here, we performed bulk RNA-seq of mixed male and female adult flies to provide evidence for annotation of our hybrid assembly of the Drosophila palustris genome.
Project description:The observation that animal morphology tends to be conserved during the embryonic phylotypic period led to the proposition that embryogenesis diverges more extensively early and late than in the middle, known as the hourglass model. This pattern of conservation is thought to reflect a major constraint on the evolution of animal body plans. Despite a wealth of morphological data confirming that there is often remarkable divergence in the early and late embryos of species from the same phylum, it is not yet known to what extent gene expression evolution, which plays a central role in the elaboration of different animal forms, underpins the morphological hourglass. Here we address this question using species-specific microarrays designed from six sequenced Drosophila species. Although it is generally appreciated that gene expression divergence plays a key role in the evolution of morphological diversity, no studies to date have addressed the extent to which expression divergence underpins the hourglass pattern at the genome-wide level. We test the molecular basis of the hourglass model of developmental evolution using gene expression data from six Drosophila species with sequenced genomes (D. ananassae, D. melanogaster, D. persimilis, D. pseudoobscura, D. simulans, and D. virilis) thereby enabling unambiguous quantitative comparisons across orthologous genes for a set of species separated by up to 40 million years. Gene expression levels were measured for 3019 genes, known to be expressed during embryonic development from RNA in situ data, at 2 hour intervals for the majority of embryogenesis using a microarray time-course with three biological replicates per species and four species-specific probes per gene.