At the base of branch 0, the Chinese populations 0.PE4 and 0.PE7 are intermingled with the populations 0.PE1 through 0.PE3 from the former Soviet Union (FSU) (Fig. 2). Isolates from outside China or the FSU were only found on branches 1 (1.ORI and 1.ANT) and 2 (2.ANT and 2.MED), suggesting that plague originated in China or the FSU. Consistent with a Chinese source, the average phylogenetic diversity among isolates was greater in China than within other countries (99% bootstrap confidence intervals: China (0.23–0.32), elsewhere (0.029–0.058); Welch t-test: P < 2.2 × 10−16). The genomes tree suggests that 0.PE2 (FSU) is the oldest population, but 0.PE7, isolated in China, is at least as old according to SNP typing and is considerably older according to genomic sequencing (R. Yang, personal communication). Our observations thus suggest that pestis evolved in China and spread to other areas on multiple occasions.Y.
这个研究不是要求证黑死病在哪里首先爆发，基因序列也无法说明，这个研究只是证实鼠疫菌的最初来源，这因该很清楚吧？
