Evidence map›Paper›PMID 32052832›Full record

ArticleGigaScience2020

GC bias affects genomic and metagenomic reconstructions, underrepresenting GC-poor organisms.

Patrick Denis Browne, Tue Kjærgaard Nielsen, Witold Kot, Anni Aggerholm, M Thomas P Gilbert, Lara Puetz, Morten Rasmussen, Athanasios Zervas, Lars Hestbjerg Hansen

Open access · goldAbstract read
In one paragraph

Article in GigaScience, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 116 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
116citing papers in PubMed, 1 pooled it
7.9field-weighted citation impact, top 2% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

116 citing papers in PubMed, 1 synthesis or guideline pooled it, 197 citations in OpenAlex.

  1. Systematic Review: Long-Read Sequencing in Algal Studies.International journal of molecular sciences · 2026
    Pooled it
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  19. PCNE: A Tool for Plasmid Copy Number Estimation.Bioinformatics and biology insights · 2026
    Article
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56 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

9 authors at 4 institutions in 2 countries.

Patrick Denis BrowneDepartment of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C, 1871, Denmark.
Tue Kjærgaard NielsenDepartment of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C, 1871, Denmark.
Witold KotDepartment of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C, 1871, Denmark.
Anni AggerholmDepartment of Hematology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, Aarhus N, 8200, Denmark.
M Thomas P GilbertThe GLOBE Institute, Faculty of Health and Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, Copenhagen N, 2200, Denmark.
Lara PuetzThe GLOBE Institute, Faculty of Health and Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, Copenhagen N, 2200, Denmark.
Morten RasmussenDepartment of Genetics, School of Medicine, Stanford University, 291 Campus Drive, Stanford, CA 94305-5051, USA.
Athanasios ZervasDepartment of Environmental Science, Aarhus University, Frederiksborgvej 399, Roskilde, 4000, Denmark.
Lars Hestbjerg HansenDepartment of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C, 1871, Denmark.
University of Copenhagen · DKAarhus University · DKAarhus University Hospital · DKStanford University · US

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundMetagenomic sequencing is a well-established tool in the modern biosciences. While it promises unparalleled insights into the genetic content of the biological samples studied, conclusions drawn are at risk from biases inherent to the DNA sequencing methods, including inaccurate abundance estimates as a function of genomic guanine-cytosine (GC) contents.

resultsWe explored such GC biases across many commonly used platforms in experiments sequencing multiple genomes (with mean GC contents ranging from 28.9% to 62.4%) and metagenomes. GC bias profiles varied among different library preparation protocols and sequencing platforms. We found that our workflows using MiSeq and NextSeq were hindered by major GC biases, with problems becoming increasingly severe outside the 45-65% GC range, leading to a falsely low coverage in GC-rich and especially GC-poor sequences, where genomic windows with 30% GC content had >10-fold less coverage than windows close to 50% GC content. We also showed that GC content correlates tightly with coverage biases. The PacBio and HiSeq platforms also evidenced similar profiles of GC biases to each other, which were distinct from those seen in the MiSeq and NextSeq workflows. The Oxford Nanopore workflow was not afflicted by GC bias.

conclusionsThese findings indicate potential sources of difficulty, arising from GC biases, in genome sequencing that could be pre-emptively addressed with methodological optimizations provided that the GC biases inherent to the relevant workflow are understood. Furthermore, it is recommended that a more critical approach be taken in quantitative abundance estimates in metagenomic studies. In the future, metagenomic studies should take steps to account for the effects of GC bias before drawing conclusions, or they should use a demonstrably unbiased workflow.

Indexed as

Base CompositionGenome, BacterialMetagenomeBiasFusobacteriumHigh-Throughput Nucleotide SequencingMetagenomicsNanopore SequencingSoftwareGC biashigh-throughput sequencingIlluminametagenomicsOxford NanoporePacBio

Identifiers

PMID32052832
PMCPMC7016772
OpenAlexW3005642314

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.