High-molecular weight DNA extraction, clean-up and size selection for long-read sequencing

PLoS One. 2021 Jul 15;16(7):e0253830. doi: 10.1371/journal.pone.0253830. eCollection 2021.

Abstract

Rapid advancements in long-read sequencing technologies have transformed read lengths from bps to Mbps, which has enabled chromosome-scale genome assemblies. However, read lengths are now becoming limited by the extraction of pure high-molecular weight DNA suitable for long-read sequencing, which is particularly challenging in plants and fungi. To overcome this, we present a protocol collection; high-molecular weight DNA extraction, clean-up and size selection for long-read sequencing. We optimised a gentle magnetic bead based high-molecular weight DNA extraction, which is presented here in detail. The protocol circumvents spin columns and high-centrifugation, to limit DNA fragmentation. The protocol is scalable based on tissue input, which can be used on many species of plants, fungi, reptiles and bacteria. It is also cost effective compared to kit-based protocols and hence applicable at scale in low resource settings. An optional sorbitol wash is listed and is highly recommended for plant and fungal tissues. To further remove any remaining contaminants such as phenols and polysaccharides, optional DNA clean-up and size selection strategies are given. This protocol collection is suitable for all common long-read sequencing platforms, such as technologies offered by PacBio and Oxford Nanopore. Using these protocols, sequencing on the Oxford Nanopore MinION can achieve read length N50 values of 30-50 kb, with reads exceeding 200 kb and outputs ranging from 15-30 Gbp. This has been routinely achieved with various plant, fungi, animal and bacteria samples.

MeSH terms

  • Animals
  • DNA / genetics
  • DNA / isolation & purification
  • DNA, Fungal / genetics
  • DNA, Fungal / isolation & purification
  • DNA, Plant / genetics
  • DNA, Plant / isolation & purification
  • Fungi / genetics
  • High-Throughput Nucleotide Sequencing* / methods
  • Molecular Weight*
  • Sequence Analysis, DNA* / methods

Substances

  • DNA
  • DNA, Plant
  • DNA, Fungal

Grants and funding

A.J. and B.S. received sequencing funds from Bioplatforms Australia, as part of the Genomics for Australian Pants initiative www.genomicsforaustralianplants.com J.B. received funds from an Australian Research Council Centre of Excellence (Plant Energy Biology) (CE140100008) and Discovery Project (DP150103591) www.arc.gov.au B.S. received funds from an Australian Research Council Future Fellowship (FT180100024) www.arc.gov.au The funders had and will not have a role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.