The current epidemic of Zika virus (ZIKV) in the Americas is particularly alarming given its confirmed neuropathological associations,such as fetal microcephaly and Guillain-Barre syndrome.As most of the involved ZIKV strains share over 99.5% genome sequence identity,the microevolutionary relationships between these strains are difficult to uncover[1].Here,we undertook an alternative strategy to track the evolution of ZIKV through comprehensive analysis of all SNPs between the 48 currently identified human strains,which can be used as "molecular footprints"[2].