An acute respiratory syndrome (COVID-19), caused by a novel coronavirus (SARS-CoV-2) with a high rate of morbidity and elevate mortality, has emerged as one of the most important threats to humankind in the last centuries. Rigorous determination of SARS-CoV-2 infectivity is ver y difficult owing to the continuous evolution of the virus, with its single nucleotide polymorphism (SNP) variants and many lineages. However, it is urgently necessa r y to study the virus in depth, to understand the mechanism of its pathogenicity and virulence, and to develop effective therapeutic strategies. The present contribution summarizes in a succinct way the current knowledge on the evolutionar y and structural features of the virus, with the aim of clarifying its mutational pattern and its possible role in the ongoing pandemic . (c) 2020 Elsevier Inc. All rights reserved.