RESUMO
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.
Assuntos
Doenças Transmissíveis Emergentes/história , Evolução Molecular , Vírus da Hepatite B/classificação , Vírus da Hepatite B/genética , Hepatite B/história , América , Ásia , Povo Asiático , Doenças Transmissíveis Emergentes/virologia , Europa (Continente) , Variação Genética , Genômica , Hepatite B/virologia , História Antiga , Humanos , Paleontologia , Filogenia , População Branca , Indígena Americano ou Nativo do AlascaRESUMO
This study continues a series of studies by Stewart and Merbs on vertebral column variations in Eskimo groups. The focus is on so called cranio-caudal shifts in spine patterning. The study is performed on a skeletal sample of ancient Eskimos from Siberia (Ekven site, Chukotka) and comparative samples representing population groups of European and African ancestry. In addition to these, literature data are used for comparative analysis to assess the pattern of cranio-caudal border shifts on intra-specific level. The result confirms the presence of significantly increased predisposition of the Eskimos to caudal shifts in spine patterning, expressed both as increased frequencies of complete caudal shifts of thoraco-lumbar and lumbo-sacral borders, as well as minor variations in vertebrae morphology, including variation in the type of articular processes (thoracic/lumbar types) and the position of costo-central articulation at T9 level. Hypotheses explaining this specific character of the Eskimo/Inuit groups are proposed and explored, including gene drift, influence of environmental factors and association with morphological characteristics adaptive to survival in the Arctic. One of the explanations may be the association with characteristic form and size of the thoracic cage that distinguishes the Arctic groups such as Eskimos and Chukchi from groups leaving in more southern areas. This needs to be tested on other groups, living in similar conditions
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Assuntos
Humanos , Inuíte , Esqueleto/anatomia & histologia , Crânio/anatomia & histologia , Vértebras Cervicais/anatomia & histologia , Nativos do Alasca , AntropologiaRESUMO
Different variants of the ninth and tenth thoracic vertebrae are described in the literature with little information on their prevalence in human populations. To review this question, 5 osteological samples from different geographical areas were studied for the presence of costal facets on the eighth (T8), ninth (T9) and tenth (T10) thoracic vertebrae. We found that inferior costal facets on vertebral centrum were absent bilaterally in 1.5% of T8 and in 46% of T9; costal facets on both T10 transverse processes were absent in 39% of cases. Absence of inferior costal facets on the T8 and T9 centrum and costal facets on the T10 transverse processes was positively associated with cranial shifts at regional borders of the spine. However, additional analysis revealed that the position of the costo-central articulation at the level of T8 and T9 as well as the position of the most inferior "typical" thoracic vertebra significantly depended on sex (p<0.001). Sex differences were most pronounced at the level of T9 where females showed very frequent absence of inferior costal facets (76% of cases compared to 47% in males). This suggests a difference in an average 10th rib position in relation to the spine in females. Significant sex differences in the position of the most inferior "typical" thoracic vertebra may be partially explained by the fact that females in general are more likely to develop some forms of cranial shifts. However, according to the literature, the female axial skeleton possesses a complex of morphological features that is seen as an adaptation to pregnancy. In this view, the different position of the female 10th rib may be one component of the complex
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