Ancient dental calculus reveals oral microbiome shifts associated with lifestyle and disease in Great Britain.

The prevalence of chronic, non-communicable diseases has risen sharply in recent decades, especially in industrialized countries. While several studies implicate the microbiome in this trend, few have examined the evolutionary history of industrialized microbiomes. Here we sampled 235 ancient dental calculus samples from individuals living in Great Britain (∼2200 BCE to 1853 CE), including 127 well-contextualized London adults. We reconstructed their microbial history spanning the transition to industrialization. After controlling for oral geography and technical biases, we identified multiple oral microbial communities that coexisted in Britain for millennia, including a community associated with Methanobrevibacter, an anaerobic Archaea not commonly prevalent in the oral microbiome of modern industrialized societies. Calculus analysis suggests that oral hygiene contributed to oral microbiome composition, while microbial functions reflected past differences in diet, specifically in dairy and carbohydrate consumption. In London samples, Methanobrevibacter-associated microbial communities are linked with skeletal markers of systemic diseases (for example, periostitis and joint pathologies), and their disappearance is consistent with temporal shifts, including the arrival of the Second Plague Pandemic. This suggests pre-industrialized microbiomes were more diverse than previously recognized, enhancing our understanding of chronic, non-communicable disease origins in industrialized populations.

Genomic autopsy to identify underlying causes of pregnancy loss and perinatal death.

Pregnancy loss and perinatal death are devastating events for families. We assessed 'genomic autopsy' as an adjunct to standard autopsy for 200 families who had experienced fetal or newborn death, providing a definitive or candidate genetic diagnosis in 105 families. Our cohort provides evidence of severe atypical in utero presentations of known genetic disorders and identifies novel phenotypes and disease genes. Inheritance of 42% of definitive diagnoses were either autosomal recessive (30.8%), X-linked recessive (3.8%) or autosomal dominant (excluding de novos, 7.7%), with risk of recurrence in future pregnancies. We report that at least ten families (5%) used their diagnosis for preimplantation (5) or prenatal diagnosis (5) of 12 pregnancies. We emphasize the clinical importance of genomic investigations of pregnancy loss and perinatal death, with short turnaround times for diagnostic reporting and followed by systematic research follow-up investigations. This approach has the potential to enable accurate counseling for future pregnancies.

Epilepsy diagnosis based on one unprovoked seizure and ≥60% risk. A systematic review of the etiologies.

BACKGROUND: According to the International League Against Epilepsy (ILAE) criteria, epilepsy can be diagnosed after one unprovoked (or reflex) seizure when there is a ≥60% of seizure recurrence in the next decade. The application of this diagnostic criterion, however, is challenging because the risk of recurrence based on different etiologies is not easily retrievable from the literature. OBJECTIVE: To assess etiologies that permit a diagnosis of epilepsy after a single unprovoked seizure. METHODS: We conducted a systematic review of the literature search using PubMed, Scopus, and Cochrane library from January 1950 to December 2020 with the keywords: recurrence, risk of recurrence, absolute risk, risk ratio, risk, seizures, epilepsy, structural, infectious, metabolic, immune, and genetic. We included articles that reported estimates of risks of a subsequent unprovoked seizure. Etiologies were categorized according to the ILAE epilepsy classification. The quality of the evidence was evaluated with PRISMA. Descriptive statistics were used. RESULTS: A total of 25,044 articles resulted from searching three databases. After authors removed duplicates, 18,911 articles remained. We screened by title and abstract, 40 articles were reviewed and finally, two articles were included. The mean follow-up was 8 years and the mean for a risk to present a subsequent unprovoked seizure was 66.6% and included structural etiologies as stroke, traumatic brain injury, cavernous malformation, arteriovenous malformation, and neuroinfections (unspecified agents). Study quality characteristics are classified with low strength of evidence and moderate-quality cohort. CONCLUSIONS: We found that stroke, traumatic brain injury, cavernous or arteriovenous malformations, and unspecified CNS infections can meet the epilepsy diagnosis after one unprovoked seizure based on low strength of evidence and moderate quality of cohorts.

Laboratory contamination over time during low-biomass sample analysis.

Bacteria are not only ubiquitous on earth but can also be incredibly diverse within clean laboratories and reagents. The presence of both living and dead bacteria in laboratory environments and reagents is especially problematic when examining samples with low endogenous content (e.g., skin swabs, tissue biopsies, ice, water, degraded forensic samples or ancient material), where contaminants can outnumber endogenous microorganisms within samples. The contribution of contaminants within high-throughput studies remains poorly understood because of the relatively low number of contaminant surveys. Here, we examined 144 negative control samples (extraction blank and no-template amplification controls) collected in both typical molecular laboratories and an ultraclean ancient DNA laboratory over 5 years to characterize long-term contaminant diversity. We additionally compared the contaminant content within a home-made silica-based extraction method, commonly used to analyse low endogenous content samples, with a widely used commercial DNA extraction kit. The contaminant taxonomic profile of the ultraclean ancient DNA laboratory was unique compared to modern molecular biology laboratories, and changed over time according to researcher, month and season. The commercial kit also contained higher microbial diversity and several human-associated taxa in comparison to the home-made silica extraction protocol. We recommend a minimum of two strategies to reduce the impacts of laboratory contaminants within low-biomass metagenomic studies: (a) extraction blank controls should be included and sequenced with every batch of extractions and (b) the contributions of laboratory contamination should be assessed and reported in each high-throughput metagenomic study.

Normas de la Revista Científica Odontológica para los autores de artículos / Revista Científica Odontológica guidelines for the authors of articles

La Revista Científica Odontológica es el órgano oficial de difusión científica de la carrera de Estomatología de la Universidad Científica del Sur. Es una publicación arbitrada por pares, de periodicidad semestral (enero-junio, julio-diciembre), de ámbito y difusión mundial. (AU)

Neanderthal behaviour, diet, and disease inferred from ancient DNA in dental calculus.

Recent genomic data have revealed multiple interactions between Neanderthals and modern humans, but there is currently little genetic evidence regarding Neanderthal behaviour, diet, or disease. Here we describe the shotgun-sequencing of ancient DNA from five specimens of Neanderthal calcified dental plaque (calculus) and the characterization of regional differences in Neanderthal ecology. At Spy cave, Belgium, Neanderthal diet was heavily meat based and included woolly rhinoceros and wild sheep (mouflon), characteristic of a steppe environment. In contrast, no meat was detected in the diet of Neanderthals from El Sidrón cave, Spain, and dietary components of mushrooms, pine nuts, and moss reflected forest gathering. Differences in diet were also linked to an overall shift in the oral bacterial community (microbiota) and suggested that meat consumption contributed to substantial variation within Neanderthal microbiota. Evidence for self-medication was detected in an El Sidrón Neanderthal with a dental abscess and a chronic gastrointestinal pathogen (Enterocytozoon bieneusi). Metagenomic data from this individual also contained a nearly complete genome of the archaeal commensal Methanobrevibacter oralis (10.2× depth of coverage)-the oldest draft microbial genome generated to date, at around 48,000 years old. DNA preserved within dental calculus represents a notable source of information about the behaviour and health of ancient hominin specimens, as well as a unique system that is useful for the study of long-term microbial evolution.

WDR62 missense mutation in a consanguineous family with primary microcephaly.

We report on a consanguineous couple with two affected sons who presented with primary microcephaly and moderate to severe intellectual disabilities. A SNP array uncovered two overlapping regions of copy-neutral absence of heterozygosity (AOH) in both sibs. This led to sequencing of WDR62, a gene that codes for a spindle pole protein recently identified as a cause of primary microcephaly. A homozygous missense mutation in WDR62, p.E400K, was found in both boys and segregated with the condition in this family. WDR62 is one of seven genes responsible for autosomal recessive primary microcephaly (MCPH), and appears to be one of the most frequently involved in MCPH following ASPM. Studies of ASPM and WDR62 should perhaps be pursued in all cases of primary microcephaly with or without gross brain malformations.

Context-dependent individualization of nucleotides and virtual genomic hybridization allow the precise location of human SNPs.

We have entered the era of individual genomic sequencing, and can already see exponential progress in the field. It is of utmost importance to exclude false-positive variants from reported datasets. However, because of the nature of the used algorithms, this task has not been optimized to the required level of precision. This study presents a unique strategy for identifying SNPs, called COIN-VGH, that largely minimizes the presence of false-positives in the generated data. The algorithm was developed using the X-chromosome-specific regions from the previously sequenced genomes of Craig Venter and James Watson. The algorithm is based on the concept that a nucleotide can be individualized if it is analyzed in the context of its surrounding genomic sequence. COIN-VGH consists of defining the most comprehensive set of nucleotide strings of a defined length that map with 100% identity to a unique position within the human reference genome (HRG). Such set is used to retrieve sequence reads from a query genome (QG), allowing the production of a genomic landscape that represents a draft HRG-guided assembly of the QG. This landscape is analyzed for specific signatures that indicate the presence of SNPs. The fidelity of the variation signature was assessed using simulation experiments by virtually altering the HRG at defined positions. Finally, the signature regions identified in the HRG and in the QG reads are aligned and the precise nature and position of the corresponding SNPs are detected. The advantages of COIN-VGH over previous algorithms are discussed.

Genetic characterization of indigenous peoples from Oaxaca, Mexico, and its relation to linguistic and geographic isolation.

We used 15 short tandem repeat (STR) loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, VWA, TPOX, D18S51, D5S818, and FGA) to genetically characterize 361 individuals from 11 indigenous populations (Amuzgo, Chinanteco, Chontal, Huave, Mazateco, Mixe, Mixteco, Triqui, Zapoteco del Istmo, Zapoteco del Valle, and Zoque) from Oaxaca, Mexico. We also used previously published data from other Mexican peoples (Maya, Chol, Tepehua, Otomí, and Mestizos from northern and central Mexico) to delineate genetic relations, for a total of 541 individuals. Average heterozygosity (H) was lower in most populations from Oaxaca (range 0.687 in Zoque to 0.756 in Chontal) than values observed in Mestizo populations from Mexico (0.758 and 0.793 in central and northern Mestizo, respectively) but higher than values observed in other Amerindian populations from South America; the same relation was true for the number of alleles (n(a) ). We tested (using the software Structure) whether major geographic or linguistic barriers to gene flow existed among the populations of Oaxaca and found that the populations appeared to constitute one or two genetic groups, suggesting that neither geographic location nor linguistics had an effect on the genetic structure of these culturally and linguistically highly diverse indigenous peoples. Moreover, we found a low but statistically significant between-population differentiation. In addition, the genetic structure of Oaxacan populations did not fit an isolation-by-distance model. Finally, using AMOVA and a Bayesian clustering approach, we did not detect significant geographic or linguistic barriers to gene flow within Oaxaca. These results suggest that the indigenous communities of Oaxaca, although culturally isolated, can be genetically defined as a large, nearly panmictic population in which migration could be a more important population mechanism than genetic drift. Finally, compared with outgroups in Mexico (both indigenous peoples and Mestizos), three groups were apparent. Among them, only the Otomí population from Hidalgo has a different culture and language.