Researchers from the UK catalog structure variants in the human genome using high-coverage genome sequences for more than 900 individuals from populations around the world who were sampled for the Human Genome Diversity panel. Compared to a human reference genome, these sequences contained more than 126,000 variants, including a slew of structural changes not reported previously and variants with distinct frequencies from one population to the next. When the team took a closer look at 25 genomes assessed by linked-read sequencing, meanwhile, it identified some 1.9 million bases of sequence not found in version GRCh38 of the human reference genome. "Our results illustrate the limitation of a single human reference," the authors note, "and the need for high-quality genomes from diverse populations to fully discover and understand human genetic variation." GenomeWeb has more on the study.
A team from China takes a look at proteomic and metabolomic profiles of blood serum samples from individuals diagnosed with COVID-19, including 28 patients with severe forms of the disease. Using stable isotope-labeled proteomics and ultra performance liquid chromatography/tandem mass spec, the researchers quantified blood levels of nearly 900 proteins and 941 metabolites in 46 individuals with severe or non-severe SARS-CoV-2 infections, comparing them with proteomic and metabolomic profiles in blood samples from dozens of healthy individuals or individuals with non-COVID-19 conditions. With the patterns detected there, the authors came up with a proteomics- and metabolomics-informed machine learning model that showed promise for distinguishing between severe and non-severe COVID-19 cases in additional patient cohorts.
Tissue in the nose and upper airway may be more susceptible to SARS-CoV-2 infections than parts of the human respiratory tract that are deeper in the lung, according to a reverse genetics study by investigators at the University of North Carolina at Chapel Hill and elsewhere. After developing reporter versions of SARS-CoV-2 and SARS-CoV that were tagged with fluorescent proteins, the team explored cross-reactivity between antibodies targeting the distinct coronaviruses, along with SARS-CoV-2 infectivity in cultured cells from the upper or lower respiratory tract. Consistent with the enhanced expression of the SARS-CoV-2 receptor ACE2 in cells from the upper respiratory tract, the results suggested upper airway cell types may be more prone to SARS-CoV-2 infection than cells in the lower respiratory tract.