Black Death genetic code 'built'

[Emily]

http://www.pnas.org/content/108/38/E746.full

PNAS Plus: From the Cover: Targeted enrichment of ancient pathogens yielding the pPCP1 plasmid of Yersinia pestis from victims of the Black Death PNAS 2011 108 (38) E746?E752; published ahead of print August 29, 2011, doi:10.1073/pnas.1105107108
Verena J. Schuenemann,
Kirsten Bos,
Sharon DeWitte,
Sarah Schmedes,
Joslyn Jamieson,
Alissa Mittnik,
Stephen Forrest,
Brian K. Coombes,
James W. Wood,
David J. D. Earn,
William White,
Johannes Krause,
and Hendrik N. Poinar

Abstract

Although investigations of medieval plague victims have identified Yersinia pestis as the putative etiologic agent of the pandemic, methodological limitations have prevented large-scale genomic investigations to evaluate changes in the pathogen's virulence over time. We screened over 100 skeletal remains from Black Death victims of the East Smithfield mass burial site (1348?1350, London, England). Recent methods of DNA enrichment coupled with high-throughput DNA sequencing subsequently permitted reconstruction of ten full human mitochondrial genomes (16 kb each) and the full pPCP1 (9.6 kb) virulence-associated plasmid at high coverage. Comparisons of molecular damage profiles between endogenous human and Y. pestis DNA confirmed its authenticity as an ancient pathogen, thus representing the longest contiguous genomic sequence for an ancient pathogen to date. Comparison of our reconstructed plasmid against modern Y. pestis shows identity with several isolates matching the Medievalis biovar; however, our chromosomal sequences indicate the victims were infected with a Y. pestis variant that has not been previously reported. Our data reveal that the Black Death in medieval Europe was caused by a variant of Y. pestis that may no longer exist, and genetic data carried on its pPCP1 plasmid were not responsible for the purported epidemiological differences between ancient and modern forms of Y. pestis infections.

Fig. P1.
(A) Skeletons removed from East Smithfield Gravesite in 1986?1988. (B) Our sampling strategy was to remove molars from the jaws, extract the powdered roots for DNA, and replace the molars back into the appropriate positions.

Another thread on this topic:
Emerg Infect Dis. Body Lice, Yersinia pestis Orientalis, and Black Death

 

[Shiloh]

Black Death genetic code 'built'

Source: http://www.bbc.co.uk/news/health-15278366

2 October 2011 Last updated at 13:02 ET

Black Death genetic code 'built'
By Matt McGrath Science reporter, BBC World Service


The genetic code of the germ that caused the Black Death has been reconstructed by scientists for the first time.

The researchers extracted DNA fragments of the ancient bacterium from the teeth of medieval corpses found in London.

They say the pathogen is the ancestor of all modern plagues.

The research, published in the journal Nature, suggests the 14th Century outbreak was also the first plague pandemic in history...

 

[Giuseppe]

Re: Black Death genetic code 'built'

[Source: Nature, full text: (LINK). Abstract, edited.]

A draft genome of Yersinia pestis from victims of the Black Death

• Kirsten I. Bos, Verena J. Schuenemann, G. Brian Golding, Hern?n 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

<DL><DT>Journal name: Nature <DT>Year published: (2011) <DT>DOI: doi:10.1038/nature10549 <DT>Received 25 July 2011 <DT>Accepted 09 September 2011 <DT>Published online 12 October 2011</DT><DT> </DT></DL>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 standard<SUP>1</SUP>. 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.
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[Story]

Re: Black Death genetic code 'built'

Poinar says the ancient Black Death DNA looks so similar to Yersinia pestis that still infects people today that researchers believe the medieval strain must be the ancestor of all modern strains.

That suggests this particular disease probably wasn't around centuries earlier and couldn't have caused the Plague of Justinian, another famous epidemic that devastated the Eastern Roman Empire in 541-542.

"More likely is that it was caused by another pathogen altogether that we haven't really considered yet," says Poinar.

http://www.npr.org/blogs/health/2011/10/13/141276449/decoded-dna-reveals-details-of-black-death-germ