Highly matching Coronavirus-like short sequences can be retrieved from environmental metagenomes

Abstract BackgroundThe ongoing COVID-19 pandemic has not only globally caused a high number of causalities, but is also an unprecedented challenge for scientists. False-positive virus detection tests not only aggravate the situation in the healthcare sector, but also provide ground for conspiracy theorists. Previous studies have highlighted the importance of software choice and data interpretation in virome studies. We aimed to further expand theoretical and practical knowledge in virome studies by focusing on short, virus-like DNA sequences in metagenomic data.ResultsExemplarily, analyses of metagenomic data from the dried-out Aral Sea basin in Uzbekistan showed that Coronavirus-like sequences have existed in environmental samples before the current COVID-19 crisis. In the analyzed environmental datasets, diverse Betacoronavirus-like sequences were detected, which also included SARS-CoV-2 matches. Moreover, the data sets harbored regions that show complementarity to PCR primers that are currently in use for virus detection and origin tracing.ConclusionsOur study confirms the importance of parameter selection, especially in terms of read length, for reliable virome profiling. Natural environments are an important source of Coronavirus-like nucleotide sequences that should be taken into account when virome datasets are analyzed and interpreted. Moreover, the identified test primer binding sites in metagenomic data might play an important role for the development of reliable test systems and origin tracing.