Scientists Use PacBio Long Reads to Simplify and Automate the Genome
Assembly Process, Dramatically Reduce Contig Numbers, and Resolve
Structural Variation
Two papers in Nature Biotechnology, both published online on
1, 2012 highlight the unique value for de novo genome assembly
provided by the PacBio® RS High Resolution Genetic
Analyzer from
Due to the inherent limitations of commonly used short-read sequencing
technologies, the genomes of very few species have been completely
sequenced, or “finished.” PacBio’s single molecule, real-time (SMRT®)
technology offers very long reads that reduce the number of contiguous
sequences, or contigs, to simplify and improve genome assembly. These
multi-kilobase reads allow scientists to sequence through long repeat
regions and to identify structural variation, which are common in
genomes but not possible to resolve completely with short-read
platforms. As a result, PacBio long reads can lead to final assemblies
that match—and in some cases even exceed—the quality that previously
counted as “finished,” approaching the gold standard of a perfect genome.
In the publication from Koren et al., titled “Hybrid error correction
and de novo assembly of single-molecule sequencing reads,” the authors
demonstrate a new pipeline for assembly of the parrot genome. Using
PacBio long reads in combination with high-accuracy short reads and an
updated version of Celera Assembler, they assembled for the first time
regulatory regions of genes involved in vocal learning circuits. The
hybrid reads represent the most complete assembled bird genome now
available.
“Repetitive regions are the biggest impediment to all assembly
algorithms and sequencing technologies as they introduce ambiguity in
the reconstruction of the genome,” said
of
Countermeasures Center. “Using the long reads we have access to longer
sequences, which increases the probability of spanning a repeat and
leads to better assemblies at lower depths than short reads.”
A separate publication from Bashir et al., titled “A hybrid approach for
the automated finishing of bacterial genomes,” describes combining
contigs from second-generation sequencing technologies with PacBio
sequence data for the cholera strain responsible for the 2010 Haitian
outbreak. The authors show that their hybrid assembly resolved complex
regions with several repeats and suggest that the approach offers a
solution for “rapid identification and assembly of full microbial
genomes.”
“The publication of these two studies is evidence of how our long-read
technology is emerging as the gold standard for finishing genome
assemblies and identifying, annotating and deciphering genomic
structure,” said
Biosciences. “Moreover, investigators are finding creative ways to take
advantage of the unique benefits provided by our SMRT sequencing and
enabling scientific applications that are simply not possible with
short-read sequencing platforms.”
The Nature Biotechnology publication details are as follows:
-
“Hybrid error correction and de novo assembly of single-molecule
sequencing reads.”
Sergey Koren et al., National Biodefense Analysisand Countermeasures Center.
-
“A hybrid approach for the automated finishing of bacterial genomes.”
Ali Bashir et al.,Pacific Biosciences andMount Sinai School of .Medicine
For more information on de novo genome assembly with the PacBio®
RS, please visit our website at www.pacb.com/denovo.
About Pacific Biosciences
RS, a high resolution genetic analyzer, to help scientists solve
genetically complex problems. Based on its novel single molecule,
real-time (SMRT®) technology, the company’s products enable:
targeted sequencing to more comprehensively characterize genetic
variations; de novo genome assembly to more fully identify,
annotate and decipher genomic structures; and DNA base modification
identification to help characterize epigenetic regulation and DNA
damage. By providing access to genetic information that was previously
inaccessible, Pacific Biosciences enables scientists to increase their
understanding of biological systems.
Forward-Looking Statements
This press release contains forward-looking statements. Forward-looking
statements may contain words such as “believe,” “may,” “estimate,”
“anticipate,” “continue,” “intend,” “expect,” “plan,” the negative of
these terms, or other similar expressions, and include the assumptions
that underlie such statements. Such statements include, but are not
limited to, statements regarding the Company’s SMRT technology. These
statements are subject to known and unknown risks and uncertainties that
could cause actual results to differ materially from those expressed or
implied by such statements, including but not limited to risks discussed
from time to time in documents
has filed with the
risks identified under the section captioned “Risk Factors” in its
recently filed Quarterly Report on Form 10-Q. All forward-looking
statements are based on estimates, projections and assumptions as of the
date hereof. Pacific Biosciences undertakes no obligation to update any
forward-looking statements.
For Pacific Biosciences
nicole@bioscribe.com
or
Pacific
Biosciences
ir@pacificbiosciences.com
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