Project description:With the emergence of zebrafish as an important model organism, a concerted effort has been made to study its transcriptome. This effort is limited by gaps in zebrafish annotation, which is especially pronounced concerning transcripts dynamically expressed during zygotic genome activation (ZGA). To date, short read sequencing has been the principal technology for zebrafish transcriptome annotation. In part because these sequence reads are too short for assembly methods to resolve the full complexity of the transcriptome, the current annotation is rudimentary. By providing direct observation of full-length transcripts, recently refined long-read sequencing platforms can dramatically improve annotation coverage and accuracy. Here, we leveraged the SMRT platform to study the early ZGA-stage zebrafish transcriptome. Our analysis revealed additional novelty and complexity in the zebrafish transcriptome, identifying 2748 high confidence novel transcripts that originated from previously unannotated loci and 1835 new isoforms in previously annotated genes.
Project description:Accurate annotations of genes and their transcripts is a foundation of genomics, but no annotation technique presently combines throughput and accuracy. As a result, the GENCODE reference collection of long noncoding RNAs remains far from complete: many are fragmentary, while thousands more remain uncatalogued. To accelerate lncRNA annotation, we have developed RNA Capture Long Seq (CLS), combining targeted RNA capture with third generation long-read sequencing. We present an experimental re-annotation of the entire GENCODE intergenic lncRNA populations in matched human and mouse tissues. CLS approximately doubles the complexity of targeted loci, both in terms of validated splice junctions and transcript models. Through its identification of full-length transcript models, CLS allows the first definitive measurement of promoter features, gene structure and protein-coding potential of lncRNAs. Thus CLS removes a longstanding bottleneck of transcriptome annotation, generating manual-quality full-length transcript models at high-throughput scales.
Project description:High-throughput sequencing of Drosophila pseudoobscura and Drosophila simulans small RNAs. ~18-26nt RNAs were isolated from total RNA using PAGE, ligation to adapters requires 5' monophosphate and 3' OH.
Project description:High-throughput sequencing of Drosophila pseudoobscura and Drosophila simulans small RNAs. ~18-26nt RNAs were isolated from total RNA using PAGE, ligation to adapters requires 5' monophosphate and 3' OH. Small RNAs were cloned from Drosophila pseudoobscura (heads and pooled 0-12 and 12-24 hour embryos) and Drosophila simulans (pooled 0-12 and 12-24 hour embryos). Sequencing was performed using the Illumina 1G platform. Following removal of 3' linker sequences, the clipped sequences longer than 18 nt were kept.
Project description:Y chromosome from different Drosophila simulans were introgressed into the same genetic background. Strains showing distinct sex-ratio distortion were clustered according to the ratio of males and females observed in the progeny. Strains showing disproportionally high number of female flies in the progeny were contrasted with strains displaying the proportion of male and females flies close to 1:1. In addition, interspecific Y chromosome from Drosophila sechellia (Ysec) was compared with D. simulans Y chromosomes. Total RNA was extracted from whole flies using TRIzol (Life Technologies). The synthesis of cDNA and its labeling with fluorescent dyes (Cy3 and Cy5) as well as hybridization reactions were carried out using 3DNA protocols and reagents (Genisphere). A minimum of 2 biological replicas was used, however this number varied according to the hybridization design (See 'Branco et. al, Natural variation of the Y chromosome suppresses sex ratio distortion and modulates testis-specific gene expression in Drosophila simulans' for details of the hybridization design). Microarrays were ~18,000-feature cDNA arrays spotted with D. melanogaster cDNA PCR products. We have recently annotated these probes using the D. simulans genome. Possible biases introduced by using a D. melanogaster platform for a D. simulans genome are minimized because the probed genomes are essentially identical except for the Y chromosomes. Slides were scanned using Axon 400B scanner (Axon Instruments) and GenePix Pro 6.0 software. Foreground fluorescence of dye intensities was normalized by the Loess method in Bioconductor / Limma.