High Throughput Nanopore Sequencing of SARS-CoV-2 Viral Genomes from Patient Samples (preprint)

In late 2019, a novel coronavirus began spreading in Wuhan, China, causing a potentially lethal respiratory viral infection. By early 2020, the novel coronavirus, called SARS-CoV-2, had spread globally, causing the COVID-19 pandemic. The infection and mutation rates of SARS-CoV-2 make it amenable to tracking movement and evolution by viral genome sequencing. Efforts to develop effective public health policies, therapeutics, or vaccines to treat or prevent COVID-19 are also expected to benefit from tracking mutations of the SARS-CoV-2 virus. Here we describe a set of comprehensive working protocols, from viral RNA extraction to analysis using online visualization tools, for high throughput sequencing of SARS-CoV-2 viral genomes using a MinION instrument. This set of protocols should serve as a reliable 'how-to' reference for generating high-quality SARS-CoV-2 genome sequences with ARTIC primer sets and next-generation nanopore sequencing technology. In addition, many of the preparation, quality control, and analysis steps will be generally applicable to other sequencing platforms.

Emergence and Evolution of a Prevalent New SARS-CoV-2 Variant in the United States (preprint)

Genomic virus surveillance can lead to early identification of new variants and inform proper response during a pandemic. Using this approach, we have identified a new variant of the SARS-CoV-2 virus that emerged in the United States (U.S.) early in the coronavirus disease (COVID-19) pandemic and has become one of the most prevalent U.S variants. This new variant within the B.1.2 lineage referred to here as 20C-US, has not yet spread widely to other countries. The earliest 20C-US genomes can be traced to the southern U.S. in late May of 2020. A major early event was the rapid acquisition of five non-synonymous mutations. The changes carried by 20C-US include mutations to genes involved in virus particle maturation and release, processing of viral proteins, and RNA genome integrity and translation genes, all important for efficient and accurate virus production. In addition, 20C-US has since acquired two new non-synonymous mutations that highlight its ongoing evolution, one of which is a Q677H mutation in the spike protein adjacent to the furin cleavage site. We predict that 20C-US may already be the most dominant variant of SARS-CoV-2 in the U.S. The ongoing evolution of 20C-US, as well as other dominant region-specific variants emerging around the world, should continue to be monitored with genomic, epidemiologic, and experimental studies to understand viral evolution and predict future outcomes of the pandemic.