Biology subjects

Marta Gut

Publications and source records attributed to Marta Gut.

4 recordsLinked to original sources

bioRxiv2016

Single Cell Transcriptome Conservation in Cryopreserved Cells and Tissues

A variety of single cell RNA preparation procedures have been described. So far these protocols require fresh starting material, hindering complex study designs. We describe a sample preservation method that maintains transcripts in viable single cells and so allows to disconnect time and place of sampling from subsequent processing steps. To demonstrate the potential, we sequenced single cell transcriptomes from >1,000 fresh and conserved cells. Our results confirmed that the conservation process did not alter transcriptional profiles. This substantially broadens the scope of applications in single cell transcriptomics and could lead to a paradigm shift in future study designs.

Genomics↗

bioRxiv2014

A comprehensive multicenter comparison of whole genome sequencing pipelines using a uniform tumor-normal sample pair

As next-generation sequencing becomes a clinical tool, a full understanding of the variables affecting sequencing analysis output is required. Through the International Cancer Genome Consortium (ICGC), we compared sequencing pipelines at five independent centers (CNAG, DKFZ, OICR, RIKEN and WTSI) using a single tumor-blood DNA pair. Analyses by each center and with one standardized algorithm revealed significant discrepancies. Although most pipelines performed well for coding mutations, library preparation methods and sequencing coverage metrics clearly influenced downstream results. PCR-free methods showed reduced GC-bias and more even coverage. Increasing sequencing depth to [~]100x (two- to three-fold higher than current standards) showed a benefit, as long as the tumor:control coverage ratio remained balanced. To become part of routine clinical care, high-throughput sequencing must be globally compatible and comparable. This benchmarking exercise has highlighted several fundamental parameters to consider in this regard, which will allow for better optimization and planning of both basic and translational studies.

Genomics↗

bioRxiv2014

An Approximate Bayesian Computation Approach to Examining the Phylogenetic Relationships among the Four Gibbon Genera using Whole Genome Sequence Data

Gibbons are believed to have diverged from the larger great apes [~]16.8 Mya and today reside in the rainforests of Southeast Asia. Based on their diploid chromosome number, the family Hylobatidae is divided into four genera, Nomascus, Symphalangus, Hoolock and Hylobates. Genetic studies attempting to elucidate the phylogenetic relationships among gibbons using karyotypes, mtDNA, the Y chromosome, and short autosomal sequences have been inconclusive. To examine the relationships among gibbon genera in more depth, we performed 2nd generation whole genome sequencing to a mean of [~]15X coverage in two individuals from each genus. We developed a coalescent-based Approximate Bayesian Computation method incorporating a model of sequencing error generated by high coverage exome validation to infer the branching order, divergence times, and effective population sizes of gibbon taxa. Although Hoolock and Symphalangus are likely sister taxa, we could not confidently resolve a single bifurcating tree despite the large amount of data analyzed. Our combined results support the hypothesis that all four gibbon genera diverged at approximately the same time. Assuming an autosomal mutation rate of 1x10-9/site/year this speciation process occurred [~]5 Mya during a period in the Early Pliocene characterized by climatic shifts and fragmentation of the Sunda shelf forests. Whole genome sequencing of additional individuals will be vital for inferring the extent of gene flow among species after the separation of the gibbon genera.

Genomics↗

bioRxiv2014

Population genomics of Saccharomyces cerevisiae human isolates: passengers, colonizers, invaders.

The quest for the ecological niches of Saccharomyces cerevisiae ranged from wineries to oaks and more recently to the gut of Crabro Wasps. Here we propose the role of the human gut in shaping S. cerevisiae evolution, presenting the genetic structure of a previously unknown population of yeasts, associated with Crohns disease, providing evidence for clonal expansion within humans gut. To understand the role of immune function in the human-yeast interaction we classified strains according to their immunomodulatory properties, discovering a set of genetically homogeneous isolates, capable of inducing anti-inflammatory signals via regulatory T cells proliferation, and on the contrary, a positive association between strain mosaicism and ability to elicit inflammatory, IL-17 driven, immune responses. The approach integrating genomics with immune phenotyping showed selection on genes involved in sporulation and cell wall remodeling as central for the evolution of S. cerevisiae Crohns strains from passengers to commensals to potential pathogens.

Evolutionary Biology↗