Browsing by Author "Gerhards, Guntis"

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    Morphological characterisation and molecular sex determination of human remains from the 15th-17th centuries in Latvia
    (2015-04-01) Ščesnaite-Jerdiakova, Asta; Pliss, Liana; Gerhards, Guntis; Gordina, Elina Petersone; Gustiņa, Agnija; Pole, Ilva; Zole, Egija; Kimsis, Janis; Jansone, Inta; Ranka, Renate
    Sex determination is one of the most important and initial steps in human profile identification from archaeological material. The aim of the current study was to evaluate the application of molecular approaches alongside morphological methods for sex determination in archaeological human skeletal remains. Human skeletal remains were excavated from three cemeteries: St Gertrude Old Church, Dom Square and St Peter's Church, of 15th-17th century burials in Riga, Latvia. Morphological and molecular genetic methods, including amplification of genes AMELX/Y and SRY were used to analyse seven skeletal remains. The conducted analyses of morphological features identified sex in all seven cases (two females and five males). By molecular analyses of mediaeval DNA it was possible to determine sex in five of seven (71%) samples. In all positive cases full agreement between morphological estimation and molecular genetic methods was observed. To conclude, DNA analysis can be considered for sex identification in cases with no signs of sexual dimorphism (juvenile skeletons) or partially preserved skeletons.
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    The postmedieval Latvian oral microbiome in the context of modern dental calculus and modern dental plaque microbial profiles
    (2021-02) Kazarina, Alisa; Petersone‐Gordina, Elina; Kimsis, Janis; Kuzmicka, Jevgenija; Zayakin, Pawel; Griškjans, Žans; Gerhards, Guntis; Ranka, Renate; Rīga Stradiņš University
    Recent advantages in paleomicrobiology have provided an opportunity to investigate the composition of ancient microbial ecologies. Here, using metagenome analysis, we investigated the microbial profiles of historic dental calculus retrieved from archaeological human remains from postmedieval Latvia dated 16–17th century AD and examined the associations of oral taxa and microbial diversity with specific characteristics. We evaluated the preservation of human oral micro-biome patterns in historic samples and compared the microbial composition of historic dental cal-culus, modern human dental plaque, modern human dental calculus samples and burial soil micro-biota. Overall, the results showed that the majority of microbial DNA in historic dental calculus originated from the oral microbiome with little impact of the burial environment. Good preservation of ancient DNA in historical dental calculus samples has provided reliable insight into the composition of the oral microbiome of postmedieval Latvian individuals. The relative stability of the classifiable oral microbiome composition was observed. Significant differences between the micro-biome profiles of dental calculus and dental plaque samples were identified, suggesting microbial adaptation to a specific human body environment.
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    Tracing microbial communities associated with archaeological human samples in Latvia, 7–11th centuries AD
    (2023-10) Ķimsis, Jānis; Pokšāne, Alise; Kazarina, Alisa; Vilcāne, Antonija; Petersone-Gordina, Elina; Zayakin, Pawel; Gerhards, Guntis; Ranka, Renate
    In the grave environment, microorganisms are major ecological participants in the successional decomposition of vertebrates and could infiltrate the skeleton/skeletal material during taphonomic processes. The diversity of archaeological skeleton-associated microbial assemblages and the impact of various factors are poorly understood. This study aimed to evaluate the taxonomic microbial composition of archaeological human bone and teeth samples from the 7th to 11th centuries AD from two burial sites in Latvia. Samples were analysed by a shotgun metagenomics-based approach. The results showed a strong presence of the environmental DNA in the samples, and variability in microbial community structure between individual samples. Differences in microbial composition were observed between bone and tooth samples, as well as between different burial sites. Furthermore, the presence of endogenous ancient DNA (aDNA) in tooth samples was detected. Overall, compositions of microbial communities associated with archaeological human remains in Latvia dated 7–11th century AD were influenced by the sample type and burial location. These findings indicate that, while the content of historical DNA in archaeological samples is low, the comparison of archaeological skeleton-associated microbial assemblages across time and space, along with aDNA damage profile analysis, is important and could help to reveal putative ancient microorganisms.