1985 年 60 巻 2 号 p. 137-150
With the aim of elucidating the origin and the route of transmission of enterovirus 70 (EV70), we constructed a phylogenetic tree using the base sequence variation deduced from the oligonucleotide map of the virus genomes of 16 strains isolated between 1971 and 1981 in different parts of the world. For this purpose, we estimated the evolutionary rate of EV70, taking advantage of the fact that the dates of isolation of the strains are precisely known. Furthermore, the divergence times between viruses were estimated using base sequence variation, the evolutionary rate and the sampling times of the strains. The phylogenetic tree and the divergence times between the branches were estimated simultaneously by UPGMA. The phylogenetic tree constructed is in good agreement with epidemiological evidences of EV70, indicating the valid estimation of the tree. It is also shown that the evolutionary rate of EV70 is extremely rapid and constant.