Identification of variable sites in Sars-CoV-2 and their abundance profiles in time

The Sars-Cov-2 pandemic that we are currently experiencing is one of the worst since long time in terms of cost in terms of human lives and economic impact. Besides the source of this virus, it is also important to understand how different virus-variant change their frequency in time, because this may indicate different levels of aggressiveness, or provide useful data to trace the spreading of the virus in the population. In this work we trace 6 amino acid variant that have high frequency in Italy and Europe, but were absent or very low frequency during the first explosion in China and the initial diffusion in Europe. One of these, variant D614G in the Spike protein, appears in Germany on January 28 and since then has overcome the wild-type variant arrived from China.