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Pop, M.

Publications and source records attributed to Pop, M..

3 recordsLinked to original sources

Integrating Hi-C links with assembly graphs for chromosome-scale assembly

Long-read sequencing and novel long-range assays have revolutionized de novo genome assembly by automating the reconstruction of reference-quality genomes. In particular, Hi-C sequencing is becoming an economical method for generating chromosome-scale scaffolds. Despite its increasing popularity, there are limited open-source tools available. Errors, particularly inversions and fusions across chromosomes, remain higher than alternate scaffolding technologies. We present a novel open-source Hi-C scaffolder that does not require an a priori estimate of chromosome number and minimizes errors by scaffolding with the assistance of an assembly graph. We demonstrate higher accuracy than the state-of-the-art methods across a variety of Hi-C library preparations and input assembly sizes. The Python and C++ code for our method is openly available at https://github.com/machinegun/SALSA\n\nAuthor summaryHi-C technology was originally proposed to study the 3D organization of a genome. Recently, it has also been applied to assemble large eukaryotic genomes into chromosome-scale scaffolds. Despite this, there are few open source methods to generate these assemblies. Existing methods are also prone to small inversion errors due to noise in the Hi-C data. In this work, we address these challenges and develop a method, named SALSA2. SALSA2 uses sequence overlap information from an assembly graph to correct inversion errors and provide accurate chromosome-scale assemblies.

bioinformatics

MetaCompass: Reference-guided Assembly of Metagenomes

Metagenomic studies have primarily relied on de novo approaches for reconstructing genes and genomes from microbial mixtures. While database driven approaches have been employed in certain analyses, they have not been used in the assembly of metagenomes. Here we describe the first effective approach for reference-guided metagenomic assembly of low-abundance bacterial genomes that can complement and improve upon de novo metagenomic assembly methods. When combined with de novo assembly approaches, we show that MetaCompass can generate more complete assemblies than can be obtained by de novo assembly alone, and improve on assemblies from the Human Microbiome Project (over 2,000 samples).

bioinformatics

Scaffolding of long read assemblies using long range contact information

MotivationLong read technologies have made a revolution in de novo genome assembly by generating contigs of size orders of magnitude more than that of short read assemblies. Although the assembly contiguity has increased, it still does not span a chromosome or an arm of the chromosome, resulting in an unfinished chromosome level assembly. To address this problem, we develop a scalable and computationally efficient scaffolding method that can boost the contiguity of the assembly by a large extent using genome wide chromatin interaction data such as Hi-C. Particularly, we demonstrate an algorithm that uses Hi-C data for longer-range scaffolding of de novo long read genome assemblies.\n\nResultsWe tested our methods on two long read assemblies of different organisms. We compared our method with previously developed method and show that our approach performs better in terms of accuracy of scaffolding.\n\nAvailabilityThe software is available for free use and can be downloaded from here: https://github.com/machinegun/hi-c-scaffold\n\nContactjchin@pacificbiosciences.com

genomics