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Biomedical subjects

Mathieu Blanchette

Publications and source records attributed to Mathieu Blanchette.

2 recordsLinked to original sources

Protocol for telomere-to-telomere assembly of Borrelia genomes using a hybrid method.

Borrelia has a linear chromosome and linear plasmids capped by hairpin telomeres that short-read sequencing cannot resolve. Here, we present a protocol for telomere-to-telomere assembly of Borrelia genomes. We describe steps for spanning B. burgdorferi culture, DNA extraction, and sequencing through hybrid genome assembly to generate complete Borrelia genomes. The pipeline integrates Oxford Nanopore long reads and Illumina short reads to assemble hairpin telomeres, resolve paralogous linear and circular plasmids, and annotate and validate the assembled complete Borrelia genome. For complete details on the use and execution of this protocol, please refer to Amin et al.1.

Bioinformatics

GraphyloVar: predicting the impact of non-coding variants using a multi-species sequence model.

MOTIVATION: Understanding the functional impact of genetic variants is a key problem for precision medicine. Tools like CADD, PhyloP, and PhastCons are useful, but they often look at each position in the genome in isolation. This means they can miss important information from the evolutionary history that connects different species. In this paper, we extend our previous model, Graphylo, to predict the effects of variants. Our new model, GraphyloVar, is built to directly utilize the phylogenetic tree that relates the species. RESULTS: GraphyloVar is a deep learning model that considers both DNA sequence and evolutionary patterns from many species. It uses two main components: Graph Convolutional Networks (GCNs) to process the phylogenetic tree, and Transformer encoders to extract features from the DNA sequences. Pre-trained to predict population-level allele frequencies on the TOPMed whole-genome sequencing cohort, GraphyloVar achieves an AUROC of 0.6246 zero-shot on &#x223c;149M held-out variants, and an ensemble with CADD reaches 0.6442 (+0.020, P<10-15). Fine-tuned GraphyloVar achieves the highest AUROC across all 13 MPRA benchmark datasets. By integrating deep learning with explicit phylogenetic input, GraphyloVar offers a powerful and complementary approach to variant effect prediction that utilizes the full evolutionary history from many species to better identify and prioritize important non-coding variants. AVAILABILITY AND IMPLEMENTATION: Code and datasets are available at https://github.com/DongjoonLim/GraphyloVar under DOI: 10.5281/zenodo.20616818.

Phylogeny