Graphical representation of the genomes of the 56 fully sequenced isolates of the virus SARS-CoV-2, the cause of Covid-19. The SARS-CoV-2 genome consists of RNA (ribonucleic acid). The genomes are represented as paths, with the length of the path proportional to the size of the genome. They are colour-coded according to the percentage of the nucleotide bases guanine (G) and cytosine (C) present, with 20% as red, through orange (30%), yellow, green (40%) and blue to purple (50%). The curvature of each path is proportional to the number of repeats in the genome and the curvature direction is determined by whether the GC content is higher or lower than average. The paths have been centred and layered according to the difference of the local GC content to the average. SARS-CoV-2 emerged in Wuhan, China, in December 2019 and spread worldwide infecting tens of millions of people and causing over one million deaths.