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Review paper summarizes insights from
20 years of bacterial genome sequencing
Background
• In two decades since the first complete bacterial genome sequence, technical
improvements and subsequent increases in biological knowledge and
reduction in price have been dramatic.
Approach
• A review paper covers the progress in sequencing and analysis, specifically of
microbial genomes, over the last 20 years.
• Phylogenetic tress can be done with finer detail and the concept of pan and
core genomes has expanded our concept of species.
• New technologies allow science to begin filling the unculturable branches of the
microbial tree of life.
• As demonstrated by the E. coli genome, the core set of genes levels off quickly
(at ~3100 gene families), while the pan-genome continues to grow.
• In 1995 only two metagenomes projects were published in comparison to
20,000 today with terabytes of sequencing data available.
• Newer technologies provide new insights into functions such as methylation
and viral immunity.
# gene families
Outcomes
Significance
• Second and third generation sequencing have greatly reduced the cost of
sequencing and made it accessible to a great many more individual
investigators.
• Sequencing of bacterial genome sequences is now a standard procedure and
the information from tens of thousands of bacterial genomes has had a major
impact on the view of the bacterial world.
2
genomes sequenced
Top: genomes sequenced
Bottom: Core and pan-genome of 2085 E. coli genomes.
Core gene families have at least one member in at least
95% of genomes.
Land, et al., “Insights from 20 years of bacterial genome sequencing,” Functional Integrative Genomics, online, 2015.