New method opens window on invisible world
A new approach to studying microbes in the wild will allow scientists to sequence the genomes of individual species from complex mixtures. It marks a big advance for understanding the enormous diversity of microbial communities —including the human microbiome. The work is described in an article published May 22 in Early Online form in the journal G3: Genes|Genomes|Genetics, published by the Genetics Society of America.
Joshua N. Burton, University of Washington
Hi-C data can cluster contigs from a metagenome assembly into species. Each of the 12 species with a substantial presence in the draft assembly is represented by a cluster. Each contig is shown as a dot, with size indicating contig length, colored by species. Edge widths represent the densities of Hi-C links between the contigs shown. Only 2400 contigs are shown: the 200 largest contigs that map uniquely to each species.
“This new method will allow us to discover many currently unknown microbial species that can’t be grown in the lab, while simultaneously assembling their genome sequences,” says co-author Maitreya Dunham, a biologist at the University of Washington’s Department of Genome Sciences.
Microbial communities, whether sampled from the ocean floor or a human mouth, are made up of many different species living together. Standard methods for sequencing these communities combine the information from all the different types of microbes in the sample. The result is a hodgepodge of genes that is challenging to analyze, and unknown species in the sample are difficult to discover.
“Our approach tells us which sequence fragments in a mixed sample came from the same genome, allowing us to construct whole genome sequences for individual species in the mix,” says co-author Jay Shendure, also of the University of Washington’s Department of Genome Sciences.
The key advance was to combine standard approaches with a method that maps out which fragments of sequence were once near each other inside a cell. The cells in the sample are first treated with a chemical that links together DNA strands that are in close proximity. Only strands that are inside the same cell will be close enough to link. The DNA is then chopped into bits, and the linked portions are isolated and sequenced.
“This elegant method enables the study of microbes in the environment,” says Brenda Andrews, editor-in-chief of the journal G3: Genes|Genomes|Genetics. Andrews is also Director of the Donnelly Centre and the Charles H. Best Chair of Medical Research at the University of Toronto. “It will open many windows into an otherwise invisible world.”
At a time when personal microbiome sequencing is becoming extremely popular, this method breaks important ground in helping researchers to build a complete picture of the genomic content of complex mixtures of microorganisms. This complete picture will be crucial for understanding the impact of varying microbiome populations and the relevance of particular microorganisms for individual health.
CITATION: Species-Level Deconvolution of Metagenome Assemblies with Hi-C-Based Contact Probability Maps Joshua N. Burton, Ivan Liachko, Maitreya J. Dunham, and Jay Shendure. G3: Genes|Genomes|Genetics g3.114.011825; Early Online May 22, 2014, doi:10.1534/g3.114.011825; PMID 24855317.
FUNDING INFORMATION: This work was supported by NIH/NHGRI grant T32HG000035 (J.N.B.), NIH/NHGRI grant HG006283 (J.S.), NIH/NIGMS grant P41 GM103533 (I.L. & M.J.D.), NSF grant 1243710 (I.L. & M.J.D.), DOE/-LBL-JGI grant 7074345/DE-AC02-05CH11231 (J.S.). M.J.D. is a Rita Allen Foundation Scholar and a Fellow in the Genetic Networks program at the Canadian Institute for Advanced Research.
ABOUT G3: G3:Genes|Genomes|Genetics publishes high-quality, valuable findings, regardless of perceived impact. G3 publishes research that generates useful genetic and genomic information such as genome maps, single gene studies, QTL studies, mutant screens and advances in methods and technology, novel mutant collections, genome-wide association studies (GWAS) including gene expression, SNP and CNV studies; exome sequences related to a specific disease, personal exome and genome sequencing case, disease and population reports, and more.
Conceived by the Genetics Society of America, with its first issue published June 2011, G3 is fully open access. G3 uses a Creative Commons license that allows the most free use of the data, which anyone can download, analyze, mine and reuse, provided that the authors of the article receive credit. GSA believes that rapid dissemination of useful data is the necessary foundation for analysis that leads to mechanistic insights. It is our hope is that this strategy will spawn new discovery.
ABOUT GSA: Founded in 1931, the Genetics Society of America (GSA) is the professional scientific society for genetics researchers and educators. The Society’s more than 5,000 members worldwide work to deepen our understanding of the living world by advancing the field of genetics, from the molecular to the population level. GSA promotes research and fosters communication through a number of GSA-sponsored conferences including regular meetings that focus on particular model organisms. GSA publishes two peer-reviewed, peer-edited scholarly journals: GENETICS, which has published high quality original research across the breadth of the field since 1916, and G3:Genes|Genomes|Genetics, an open-access journal launched in 2011 to disseminate high quality foundational research in genetics and genomics. The Society also has a deep commitment to education and fostering the next generation of scholars in the field. For more information about GSA, please visit www.genetics-gsa.org. Follow GSA on Facebook at facebook.com/GeneticsGSA and on Twitter @GeneticsGSA.
Cristy Gelling | newswise
Pathogenic bacteria hitchhiking to North and Baltic Seas?
22.07.2016 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
Unconventional quasiparticles predicted in conventional crystals
22.07.2016 | Max-Planck-Institut für Chemische Physik fester Stoffe
Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.
Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...
Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases
Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...
Scaffolding and specialised workers help with the delivery – Heidelberg biochemists gain new insights into biogenesis
A type of scaffolding on which specialised workers ply their trade helps in the manufacturing process of the two subunits from which the ribosome – the protein...
Scientists at the Helmholtz Zentrum München have developed a new mass spectrometry imaging method which, for the first time, makes it possible to analyze hundreds of metabolites in fixed tissue samples. Their findings, published in the journal Nature Protocols, explain the new access to metabolic information, which will offer previously unexploited potential for tissue-based research and molecular diagnostics.
In biomedical research, working with tissue samples is indispensable because it permits insights into the biological reality of patients, for example, in...
Chemists at the University of Basel have succeeded in using computer simulations to elucidate transient structures in proteins. In the journal Angewandte Chemie, the researchers set out how computer simulations of details at the atomic level can be used to understand proteins’ modes of action.
Using computational chemistry, it is possible to characterize the motion of individual atoms of a molecule. Today, the latest simulation techniques allow...
15.07.2016 | Event News
15.07.2016 | Event News
11.07.2016 | Event News
22.07.2016 | Information Technology
22.07.2016 | Physics and Astronomy
22.07.2016 | Life Sciences