Marie Bashir Institute for Infectious Diseases and Biosecurity, Charles Perkins Centre, School of Life and Environmental Sciences and Sydney Medical School, The University of Sydney, Sydney, NSW 2006, Australia.
McMaster Ancient DNA Centre, Department of Anthropology, McMaster University, Hamilton, ON L8S 4L9, Canada.
Viruses. 2017 Sep 28;9(10):276. doi: 10.3390/v9100276.
The complete genome sequences of two strains of variola virus (VARV) sampled from human smallpox specimens present in the Czech National Museum, Prague, were recently determined, with one of the sequences estimated to date to the mid-19th century. Using molecular clock methods, the authors of this study go on to infer that the currently available strains of VARV share an older common ancestor, at around 1350 AD, than some recent estimates based on other archival human samples. Herein, we show that the two Czech strains exhibit anomalous branch lengths given their proposed age, and by assuming a constant rate of evolutionary change across the rest of the VARV phylogeny estimate that their true age in fact lies between 1918 and 1937. We therefore suggest that the age of the common ancestor of currently available VARV genomes most likely dates to late 16th and early 17th centuries and not ~1350 AD.
最近，从保存在布拉格捷克国家博物馆的人类天花标本中分离出的两株天花病毒（VARV）的全基因组序列被测定，其中一个序列估计可以追溯到 19 世纪中叶。利用分子钟方法，本研究的作者推断，目前可用的 VARV 株系比基于其他存档人类样本的一些近期估计具有更古老的共同祖先，约在公元 1350 年左右。在此，我们表明，考虑到这两个捷克株系的假定年龄，它们的异常分支长度，以及通过假设 VARV 系统发育的其余部分的进化变化率保持恒定，它们的真实年龄实际上介于 1918 年至 1937 年之间。因此，我们建议，目前可用的 VARV 基因组的共同祖先的年龄很可能追溯到 16 世纪末至 17 世纪初，而不是约公元 1350 年。
