描述了乙型肝炎病毒进化的十千年

StephenW

描述了乙型肝炎病毒进化的十千年
一项新研究追溯了乙型肝炎病毒从史前到现在的演变，揭示了病毒多样性的传播途径和变化

日期：
    2021 年 10 月 7 日
来源：
    马克斯普朗克人类历史科学研究所
概括：
    研究人员通过分析迄今为止产生的最大的古代病毒基因组数据集，揭示了自全新世早期以来乙型肝炎病毒的进化。
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乙型肝炎病毒 (HBV) 是世界范围内的主要健康问题，每年导致近 100 万人死亡。最近的古代 DNA 研究表明，HBV 已经感染人类数千年，但其过去的多样性和传播途径在很大程度上仍然未知。由来自世界各地的一大群研究人员进行的一项新研究通过检查来自约 10,500 至约 400 年前的 137 名古代欧亚人和美洲原住民的病毒基因组，提供了对 HBV 进化历史的重要见解。他们的结果突出了病毒多样性的传播途径和变化，这些变化反映了众所周知的人类迁徙和人口统计事件，以及与现在的意外模式和联系。

HBV 与美洲人民

当今的 HBV 毒株分为九种基因型，其中两种主要在美洲原住民血统中发现。该研究提供了强有力的证据，表明这些毒株来自 HBV 谱系，该谱系在更新世末期分化，并由美洲的一些第一批居民携带。

“我们的数据表明，所有已知的 HBV 基因型都来自一种菌株，这种菌株在这些人群发生分化时感染了第一批美国人的祖先及其最亲近的欧亚亲属，”潮汐研究小组的负责人兼该研究的主管丹尼斯·库纳特 (Denise Kühnert) 说。 .

史前欧洲的HBV

该研究还表明，早在 10,000 年前，在农业传播到欧洲大陆之前，该病毒就存在于欧洲的大部分地区。

马克斯普朗克进化人类学研究所考古遗传学系主任兼联合主管约翰内斯克劳斯说：“许多人类病原体被认为是在引入农业后出现的，但 HBV 显然已经影响了史前的狩猎采集人群。”的研究。

在欧洲的新石器时代过渡之后，狩猎采集者携带的 HBV 毒株被可能由该大陆第一批农民传播的新毒株所取代，这反映了与该地区农业群体扩张相关的大量基因流入。这些新的病毒谱系在整个欧亚大陆西部持续流行了近 4000 年。这些菌株的优势持续了大约 5000 年前西部草原牧民的扩张，这极大地改变了欧洲人的遗传特征，但与新的 HBV 变体的传播无关。

史前HBV的崩溃和重新出现

该研究最令人惊讶的发现之一是，在公元前 2 世纪下半叶，欧亚大陆西部的 HBV 多样性突然下降，这是一个重大文化转变时期，包括地中海东部地区大型青铜时代国家社会的崩溃.

“这可能表明在此期间一个非常大的区域的流行病学动态发生了重要变化，但我们需要更多的研究来了解发生了什么，”潮汐小组的主要作者和研究员亚瑟·科赫说。

在此之后，在欧亚大陆西部恢复的所有古老的 HBV 毒株都属于今天仍在该地区盛行的新病毒谱系。然而，似乎与该地区以前的史前多样性相关的一种变体一直持续到现在。这种史前变异已经演变成一种罕见的基因型，它似乎是最近在 HIV 大流行期间出现的，其原因仍有待了解。

StephenW

Ten millennia of hepatitis B virus evolution described
A new study traces the evolution of the hepatitis B virus from prehistory to the present, revealing dissemination routes and changes in viral diversity

Date:
    October 7, 2021
Source:
    Max Planck Institute for the Science of Human History
Summary:
    Researchers uncover the evolution of the hepatitis B virus since the Early Holocene by analyzing the largest dataset of ancient viral genomes produced to date.
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The hepatitis B virus (HBV) is a major health problem worldwide, causing close to one million deaths each year. Recent ancient DNA studies have shown that HBV has been infecting humans for millennia, but its past diversity and dispersal routes remain largely unknown. A new study conducted by a large team of researchers from all around the world provides major insights into the evolutionary history of HBV by examining the virus' genomes from 137 ancient Eurasians and Native Americans dated to between ~10,500 and ~400 years ago. Their results highlight dissemination routes and shifts in viral diversity that mirror well-known human migrations and demographic events, as well as unexpected patterns and connections to the present.

HBV and the peopling of the Americas

Present-day HBV strains are classified into nine genotypes, two of which are found predominantly in populations of Native American ancestry. The study provides strong evidence that these strains descend from an HBV lineage that diverged around the end of the Pleistocene and was carried by some of the first inhabitants of the Americas.

"Our data suggest that all known HBV genotypes descend from a strain that was infecting the ancestors of the First Americans and their closest Eurasian relatives around the time these populations diverged," says Denise Kühnert, leader of the tide research group and supervisor of the study.

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 the spread of agriculture to the continent.

"Many human pathogens are thought to have emerged after the introduction of agriculture, but HBV was clearly already affecting prehistoric hunter-gatherer populations," says 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 strains carried by hunter-gatherers were replaced by new strains that were likely spread by the continent's first farmers, mirroring the large genetic influx associated with the expansion of farming groups across the region. These new viral lineages continued to prevail throughout western Eurasia for close to 4,000 years. The dominance of these strains lasted through the expansion of Western Steppe Herders around 5,000 years ago, which dramatically altered the genetic profile of Europeans but remarkably was not associated with the spread of new HBV variants.

The collapse and re-emergence of pre-historic HBV

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

"This could point to important changes in epidemiological dynamics over a very large region during this period, but we will need more research to understand what happened," says Arthur Kocher, lead author and researcher in the tide group.

All ancient HBV strains recovered in western Eurasia after this period belonged to new viral lineages that still prevail in the region today. However, it appears that one variant related to the previous pre-historic diversity of the region has persisted to the present. This prehistoric variant has evolved into a rare genotype that seems to have emerged recently during the HIV pandemic, for reasons that remain to be understood.