Making kin

Thanks to next generation sequencing (NGS), we can now access ancient biological relationships, including ancestry and parentage, with a startling level of clarity. This has led to recentering of kinship within archaeological discourse. In this paper, we argue that blood and biology are key elements of kin-making only in so far as they are contextualized and made sense of through social relations. We argue that the conceptions of kinship that underpin archaeogenetic studies are the product of a particular historical and political context. Archaeology, with its focus on the material remains of the past, provides opportunities to examine how other forms of material and technological intervention (including ritual, exchange, and the sharing of food) facilitated the creation of kinship links not solely rooted in the human body. Here, we consider the extent to which the social salience of biological relationships identified through ancient DNA analysis can be addressed without imposing contemporary forms of familial structure and gender ideology onto the past.

Effectiveness of decontamination protocols when analyzing ancient DNA preserved in dental calculus

Ancient DNA analysis of human oral microbial communities within calcified dental plaque (calculus) has revealed key insights into human health, paleodemography, and cultural behaviors. However, contamination imposes a major concern for paleomicrobiological samples due to their low endogenous DNA content and exposure to environmental sources, calling into question some published results. Decontamination protocols (e.g. an ethylenediaminetetraacetic acid (EDTA) pre-digestion or ultraviolet radiation (UV) and 5% sodium hypochlorite immersion treatments) aim to minimize the exogenous content of the outer surface of ancient calculus samples prior to DNA extraction. While these protocols are widely used, no one has systematically compared them in ancient dental calculus. Here, we compare untreated dental calculus samples to samples from the same site treated with four previously published decontamination protocols: a UV only treatment; a 5% sodium hypochlorite immersion treatment; a pre-digestion in EDTA treatment; and a combined UV irradiation and 5% sodium hypochlorite immersion treatment. We examine their efficacy in ancient oral microbiota recovery by applying 16S rRNA gene amplicon and shotgun sequencing, identifying ancient oral microbiota, as well as soil and skin contaminant species. Overall, the EDTA pre-digestion and a combined UV irradiation and 5% sodium hypochlorite immersion treatment were both effective at reducing the proportion of environmental taxa and increasing oral taxa in comparison to untreated samples. This research highlights the importance of using decontamination procedures during ancient DNA analysis of dental calculus to reduce contaminant DNA.

Agro jauno laiku Rīgas kapsētu apbedījumu izpēte ar senās DNS analīzēm: nozīmīgākās pieejas un izpētes perspektīvas

The aim of the research is to find out how ancient DNA analysis could supplement the existing knowledge acquired with research methods like analysis of literature and sources, as well as archaeological methods, using specific early modern period burials in Riga as an example. Within the framework of the study, the ancient DNA extraction and analysis was performed. The results are connected with the archaeological and historical context of the burial, thus enabling advancement of hypotheses about the origin of specific individuals based on the population genetics theory. As a result of the study, the approximate maternal origin of three and the sex of all six of the studied individuals was determined. It was found that the buried individuals had different regions of origin, thereby confirming that the inhabitants of Riga in the early modern period were ethnically diverse.

Effectiveness of Decontamination protocols when Analyzing Ancient DNA Preserved in Dental Calculus

Ancient DNA analysis of human oral microbial communities within calcified dental plaque (calculus) has revealed key insights into human health, paleodemography, and cultural behaviors. However, contamination imposes a major concern for paleomicrobiological samples due to their low endogenous DNA content and exposure to environmental sources, calling into question some published results. Decontamination protocols (e.g. an ethylenediaminetetraacetic acid (EDTA) pre-digestion or ultraviolet radiation (UV) and bleach immersion treatments) aim to minimize the exogenous content of the outer surface of ancient calculus samples prior to DNA extraction. While these protocols are efficient, no one has systematically compared them. Here, we compare untreated dental calculus samples to four previously published decontamination protocols: a UV only treatment; a 5% sodium hypochlorite (bleach) immersion treatment; a pre-digestion in EDTA treatment; and a combined UV irradiation and 5% bleach immersion treatment. We examine their efficacy in ancient oral microbiota recovery by applying 16S rRNA gene amplicon and shotgun sequencing to ancient calculus samples from a single site. We identify ancient oral microbiota, as well as soil and skin contaminants. Overall, both the EDTA and UVB treatments are effective at reducing the proportion of environmental taxa while increasing oral taxa in relation to untreated samples.