Hepatitis B virus (HBV) infections represent a worldwide human health concern. To study the history of this pathogen, Kocher et al. identified 137 human remains with detectable levels of virus dating between 400 and 10,000 years ago. Sequencing and analyses of these ancient viruses suggested a common ancestor between 12,000 and 20,000 years ago. There is no evidence indicating that HBV was present in the earliest humans as they spread out of Africa; however, HBV was likely present in human populations before farming. Furthermore, the virus was present in the Americas by about 9000 years ago, representing a lineage sister to the viral strains found in Eurasia that diverged about 20,000 years ago. —LMZ Genomic data from more than 100 individuals elucidates hepatitis B virus evolution in ancient Eurasians and Native American genomes. Hepatitis B virus (HBV) has been infecting humans for millennia and remains a global health problem, but its past diversity and dispersal routes are largely unknown. We generated HBV genomic data from 137 Eurasians and Native Americans dated between 10,500 and 400 years ago. We date the most recent common ancestor of all HBV lineages to between 20,000 and 12,000 years ago, with the virus present in European and South American hunter-gatherers during the early Holocene. After the European Neolithic transition, Mesolithic HBV strains were replaced by a lineage likely disseminated by early farmers that prevailed throughout western Eurasia for 4000 years, declining around the end of the 2nd millennium BCE. The only remnant of this prehistoric HBV diversity is the rare genotype G, which appears to have reemerged during the HIV pandemic.
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A section at Aktulagay (west Kazakhstan), in the Peri-Tethys realm, exposes mid-neritic to upper bathyal Ypresian marls, clays and silts. These range from Zone NP10 to early Zone NP14, with abundant and diverse microfossil assemblages. Multidisciplinary analysis has identified dinoflagellate cyst, calcareous nannofossil, planktonic and benthic foraminiferid and pteropod zones and events. Calibration of a key interval in the evolution of the shark Otodus has been possible for the first time. Episodic low-oxygen facies, including sapropelic clays widely distributed in Peri-Tethys, are represented here and can be placed within a detailed biostratigraphic framework. The current lithostratigraphic terminology is modified, with the introduction of the Aktulagay Formation. Paleoenvironmental aspects are discussed; five depositional sequences are tentatively identified. This section can be correlated in detail with the succession in the North Sea Basin, with implications for paleogeographic reconstructions. High-resolution biostratigraphic calibration between disparate fossil groups makes this a key reference section for northern mid-latitude Ypresian biostratigraphy.
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