Study traces the development of hepatitis B virus from prehistory to the present

Ten millennia with hepatitis B virus development

A scientist tests a tooth in the old DNA lab at the Max Planck Institute for the Science of Human History. Credit: Raffaela Bianco

In a new paper in the journal Science, the researchers uncover the development of hepatitis B virus since the early Holocene by analyzing the largest data set of ancient viral genomes produced to date.

Hepatitis B virus (HBV) is a major health problem worldwide, causing nearly one million deaths each year. Recent old DNA studies have shown that HBV has infected humans for millennia, but its past diversity and routes of transmission are largely unknown. A new study conducted by a large team of researchers from around the world provides great insight into HBV’s evolutionary history by examining the virus’ genomes from 137 ancient Eurasians and Indians dated to between ~ 10,500 and ~ 400 years ago. Their findings highlight pathways of communication and shifts in viral diversity that reflect known human migrations and demographic events, as well as unexpected patterns and connections to the present.

HBV and the people of America

Today’s HBV strains are classified into nine genotypes, two of which are found mainly in populations of Native American ancestry. The study provides strong evidence that these strains are descended from an HBV lineage that diverged around the end of the Pleistocene and was borne by some of the first inhabitants of America.

“Our data suggest that all known HBV genotypes are descended from a tribe that infected the ancestors of the first Americans and their immediate Eurasian relatives around the time these populations diverged,” said Denise K├╝hnert, head of the tidal research group and study supervisor. .

HBV in prehistoric Europe

The study also shows that the virus was present in large parts of Europe as early as 10,000 years ago, before agriculture spread to the continent.

“Many human pathogens are thought to have originated after the introduction of agriculture, but HBV clearly influenced prehistoric hunter-gatherer populations,” said Johannes Krause, director of the Department of Archaeogenetics at the Max Planck Institute for Evolutionary Anthropology and co-supervisor of the study.

After the Neolithic transition in Europe, the HBV tribes carried by hunter-gatherers were replaced by new tribes probably scattered by the continent’s first farmers, reflecting the great genetic influx associated with the expansion of agricultural groups throughout the region. These new viral genera continued to rule throughout western Eurasia for nearly 4,000 years. The dominance of these tribes lasted through the expansion of Western Steppe Herders about 5,000 years ago, which dramatically changed the genetic profile of Europeans, but was remarkably not associated with the spread of new HBV variants.

The collapse and resurrection of prehistoric HBV

One of the most surprising findings of the study is a sudden decline in HBV diversity in western Eurasia in the second half of the 2nd millennium BCE, a time of great cultural change, including the collapse of large Bronze Age state societies in the eastern Mediterranean.

“This may point to important changes in the epidemiological dynamics of a very large region during this period, but we will need more research to understand what happened,” said Arthur Kocher, lead author and researcher in the tidal group.

All ancient HBV strains that were restored in western Eurasia after this period belonged to new viral genera that still prevail in the region today. However, it seems that a variant related to the former prehistoric diversity in the region has persisted today. This prehistoric variant has evolved into a rare genotype that appears to have emerged recently during the HIV pandemic, for reasons still to be understood.

Stone Age hepatitis B virus decoded

More information:
Arthur Kocher et al., Ten millennia of hepatitis B virus development, Science (2021). DOI: 10.1126 / science.abi5658

Provided by the Max Planck Society

Citation: Study tracks the development of hepatitis B virus from prehistory to present (2021, October 7) retrieved October 8, 2021 from html

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