英国《自然》杂志网站10月12日刊登研究报告说，一个国际研究小组利用从中世纪死者遗骸中取出的物质，测出了曾在中世纪肆虐的黑死病致病菌的基因组，结果显示现在所有种类的鼠疫杆菌都与其有关。
欧洲中世纪所称的黑死病，一般认为就是现在的鼠疫。它由鼠疫杆菌引起，曾在中世纪的欧洲大规模流行，使得西欧人口几近减半，引起巨大恐慌。
黑死病的一次主要暴发期是在1347年到1351年间，当时的伦敦为了处理病死者的尸体，曾专门建立了几块墓地。德国和加拿大等国的研究人员就是从这些墓地里的遗骸中取出相关物质，测出了黑死病致病菌的基因组。
分析显示，今天所有的鼠疫杆菌虽然还可划分出一些不同的菌株，但它们从基因上看都源于黑死病致病菌，该病菌可算得上是“瘟疫之祖”。
研究人员认为，中世纪黑死病致病菌和今天的鼠疫杆菌在基因上的差距并不大，但现在却少有大规模鼠疫流行，这并不是因为病菌本身发生了多大变化，而是因为环境等方面因素发生了变化。（生物谷 Bioon.com）
doi:10.1038/nature10549
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A draft genome of Yersinia pestis from victims of the Black Death
Kirsten I. Bos; Verena J. Schuenemann; G. Brian Golding; Hernán A. Burbano; Nicholas Waglechner; Brian K. Coombes; Joseph B. McPhee; Sharon N. DeWitte; Matthias Meyer; Sarah Schmedes; James Wood; David J. D. Earn; D. Ann Herring; Peter Bauer; Hendrik N. Poinar; Johannes Krause
Technological advances in DNA recovery and sequencing have drastically expanded the scope of genetic analyses of ancient specimens to the extent that full genomic investigations are now feasible and are quickly becoming standard1. This trend has important implications for infectious disease research because genomic data from ancient microbes may help to elucidate mechanisms of pathogen evolution and adaptation for emerging and re-emerging infections. Here we report a reconstructed ancient genome of Yersinia pestis at 30-fold average coverage from Black Death victims securely dated to episodes of pestilence-associated mortality in London, England, 1348–1350. Genetic architecture and phylogenetic analysis indicate that the ancient organism is ancestral to most extant strains and sits very close to the ancestral node of all Y. pestis commonly associated with human infection. Temporal estimates suggest that the Black Death of 1347–1351 was the main historical event responsible for the introduction and widespread dissemination of the ancestor to all currently circulating Y. pestis strains pathogenic to humans, and further indicates that contemporary Y. pestis epidemics have their origins in the medieval era. Comparisons against modern genomes reveal no unique derived positions in the medieval organism, indicating that the perceived increased virulence of the disease during the Black Death may not have been due to bacterial phenotype. These findings support the notion that factors other than microbial genetics, such as environment, vector dynamics and host susceptibility, should be at the forefront of epidemiological discussions regarding emerging Y. pestis infections.
