SARS-CoV-2 Mutant Spectra at Different Depth Levels Reveal an Overwhelming Abundance of Low Frequency Mutations

Populations of RNA viruses are composed of complex and dynamic mixtures of variant genomes that are termed mutant spectra or mutant clouds. This applies also to SARS-CoV-2, and mutations that are detected at low frequency in an infected individual can be dominant (represented in the consensus sequen...

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Autores: Martínez-González, Brenda, Soria, María Eugenia, Vázquez-Sirvent, Lucía, Ferrer-Orta, Cristina, Lobo-Vega, Rebeca, Mínguez, Pablo, Fuente, Lorena de la, Llorens, Carlos, Soriano, Beatriz, Ramos-Ruiz, Ricardo, Cortón, Marta, López-Rodríguez, Rosario, García-Crespo, Carlos, Somovilla, Pilar, Durán-Pastor, Antoni, Gallego, Isabel, Ávila, Ana Isabel de, Delgado, Soledad, Morán, Federico, López-Galíndez, Cecilio, Gómez-Castilla, Jordi, Enjuanes Sánchez, Luis, Salar-Vidal, Llanos, Esteban-Muñoz, Mario, Esteban, Jaime, Fernández-Roblas, Ricardo, Gadea, Ignacio, Ayuso, Carmen, Ruíz-Hornillos, Javier, Verdaguer, Núria, Domingo, Esteban, Perales, Celia
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2022
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:dnet:digitalcsic_::809c3ee3bc09a238f307dab6251f1aed
Acceso en línea:http://hdl.handle.net/10261/280480
Access Level:acceso abierto
Palabra clave:RNA virus
COVID-19
Ultra-deep sequencing
viral quasispecies
Mutation
Deletion
nsp12 (polymerase)
Spike
Descripción
Sumario:Populations of RNA viruses are composed of complex and dynamic mixtures of variant genomes that are termed mutant spectra or mutant clouds. This applies also to SARS-CoV-2, and mutations that are detected at low frequency in an infected individual can be dominant (represented in the consensus sequence) in subsequent variants of interest or variants of concern. Here we briefly review the main conclusions of our work on mutant spectrum characterization of hepatitis C virus (HCV) and SARS-CoV-2 at the nucleotide and amino acid levels and address the following two new questions derived from previous results: (i) how is the SARS-CoV-2 mutant and deletion spectrum composition in diagnostic samples, when examined at progressively lower cut-off mutant frequency values in ultra-deep sequencing; (ii) how the frequency distribution of minority amino acid substitutions in SARS-CoV-2 compares with that of HCV sampled also from infected patients. The main conclusions are the following: (i) the number of different mutations found at low frequency in SARS-CoV-2 mutant spectra increases dramatically (50- to 100-fold) as the cut-off frequency for mutation detection is lowered from 0.5% to 0.1%, and (ii) that, contrary to HCV, SARS-CoV-2 mutant spectra exhibit a deficit of intermediate frequency amino acid substitutions. The possible origin and implications of mutant spectrum differences among RNA viruses are discussed.