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Background Quantitative Ultrasound (QUS) methods have been widely used to assess estimated bone density. This study aimed to assess changes in estimated bone density in association with changes in body composition, physical activity, and anthropometry. Methods We examined changes in anthropometry, body composition, and physical activity associated with changes in estimated bone mineral density (measured using quantitative ultrasound with a heel ultrasound device indicating broadband ultrasound attenuation BUA and speed of sound SOS) in a follow-up sample of n = 73 young men at the beginning and again 18 weeks later at the end of basic military training. Results At the end of the basic training, the subjects were on average significantly heavier (+1.0%), slightly taller (+0.5%) and had a higher fat mass (+6.6%) and grip strength (+8.6%). A significant decrease in mean physical activity (−49.5%) and mean estimated bone density calculated with BUA (−7.5%) was observed in the paired t-test. The results of the multivariable linear regressions (backward selection) show that changes in skeletal muscle mass (delta = 2nd measurement minus 1st measurement) have negative and body weight (delta) have positive association with the speed of sound SOS (delta), while fat mass (delta) and physical activity (delta) had the strongest negative associations with estimated bone mineral density (delta). In particular, we found a negative association between fat mass (delta) and estimated bone mineral density (delta, estimated with BUA). Conclusion Our study suggests that estimated bone density from the calcaneus can change within a few months even in young and mostly healthy individuals, depending upon physical activity levels and other co-factors. Further studies including other troop types as control groups as well as on women should follow in order to investigate this public health relevant topic in more depth. To what extent the estimated bone density measurement with quantitative ult

Population bottlenecks can have dramatic consequences for the health and long-term survival of a species. Understanding of historic population size and standing genetic variation prior to a contraction allows estimating the impact of a bottleneck on the species' genetic diversity. Although historic population sizes can be modelled based on extant genomics, uncertainty is high for the last 10–20 millenia. Hence, integrating ancient genomes provides a powerful complement to retrace the evolution of genetic diversity through population fluctuations. Here, we recover 15 high-quality mitogenomes of the once nearly extinct Alpine ibex spanning 8601 BP to 1919 CE and combine these with 60 published modern whole genomes. Coalescent demography simulations based on modern whole genomes indicate population fluctuations coinciding with the last major glaciation period. Using our ancient and historic mitogenomes, we investigate the more recent demographic history of the species and show that mitochondrial haplotype diversity was reduced to a fifth of the prebottleneck diversity with several highly differentiated mitochondrial lineages having coexisted historically. The main collapse of mitochondrial diversity coincides with elevated human population growth during the last 1–2 kya. After recovery, one lineage was spread and nearly fixed across the Alps due to recolonization efforts. Our study highlights that a combined approach integrating genomic data of ancient, historic and extant populations unravels major long-term population fluctuations from the emergence of a species through its near extinction up to the recent past.

Population bottlenecks can have dramatic consequences for the health and long-term survival of a species. Understanding of historic population size and standing genetic variation prior to a contraction allows estimating the impact of a bottleneck on the species' genetic diversity. Although historic population sizes can be modelled based on extant genomics, uncertainty is high for the last 10–20 millenia. Hence, integrating ancient genomes provides a powerful complement to retrace the evolution of genetic diversity through population fluctuations. Here, we recover 15 high-quality mitogenomes of the once nearly extinct Alpine ibex spanning 8601 BP to 1919 CE and combine these with 60 published modern whole genomes. Coalescent demography simulations based on modern whole genomes indicate population fluctuations coinciding with the last major glaciation period. Using our ancient and historic mitogenomes, we investigate the more recent demographic history of the species and show that mitochondrial haplotype diversity was reduced to a fifth of the prebottleneck diversity with several highly differentiated mitochondrial lineages having coexisted historically. The main collapse of mitochondrial diversity coincides with elevated human population growth during the last 1–2 kya. After recovery, one lineage was spread and nearly fixed across the Alps due to recolonization efforts. Our study highlights that a combined approach integrating genomic data of ancient, historic and extant populations unravels major long-term population fluctuations from the emergence of a species through its near extinction up to the recent past.

Museum specimens and histologically fixed material are valuable samples for the study of historical soft tissues and represent a possible pathogen-specific source for retrospective molecular investigations. However, current methods for molecular analysis are inherently destructive, posing a dilemma between performing a study with the available technology, thus damaging the sample, and conserving the material for future investigations. Here the authors present the first tests of a non-destructive alternative that facilitates genetic analysis of fixed wet tissues while avoiding tissue damage. The authors extracted DNA from the fixed tissues as well as their embedding fixative solution, to quantify the DNA that was transferred to the liquid component. The results show that human historical DNA can be retrieved from the fixative material of medical specimens and provide new options for sampling valuable collections.

Mummified human tissues are of great interest in forensics and biomolecular archaeology. The aim of this study was to analyse post mortem DNA alterations in soft tissues in order to improve our knowledge of the patterns of DNA degradation that occur during salt mummification. In this study, the lower limb of a female human donor was amputated within 24 h post mortem and mummified using a process designed to simulate the salt dehydration phase of natural or artificial mummification. Skin and skeletal muscle were sampled at multiple time points over a period of 322 days and subjected to genetic analysis. Patterns of genomic fragmentation, miscoding lesions, and overall DNA degradation in both nuclear and mitochondrial DNA was assessed by different methods: gel electrophoresis, multiplex comparative autosomal STR length amplification, cloning and sequence analysis, and PCR amplification of different fragment sizes using a damage sensitive recombinant polymerase. The study outcome reveals a very good level of DNA preservation in salt mummified tissues over the course of the experiment, with an overall slower rate of DNA fragmentation in skin compared to muscle.

Ruminant milk and dairy products are important food resources in many European, African, and Middle Eastern societies. These regions are also associated with derived genetic variants for lactase persistence. In mammals, lactase, the enzyme that hydrolyzes the milk sugar lactose, is normally down-regulated after weaning, but at least five human populations around the world have independently evolved mutations regulating the expression of the lactase-phlorizin-hydrolase gene. These mutations result in a dominant lactase persistence phenotype and continued lactase tolerance in adulthood. A single nucleotide polymorphism (SNP) at C/T-13910 is responsible for most lactase persistence in European populations, but when and where the T-13910 polymorphism originated and the evolutionary processes by which it rose to high frequency in Europe have been the subject of strong debate. A history of dairying is presumed to be a prerequisite, but archaeological evidence is lacking. In this study, DNA was extracted from the dentine of 36 individuals excavated at a medieval cemetery in Dalheim, Germany. Eighteen individuals were successfully genotyped for the C/T-13910 SNP by molecular cloning and sequencing, of which 13 (72%) exhibited a European lactase persistence genotype: 44% CT, 28% TT. Previous ancient DNA-based studies found that lactase persistence genotypes fall below detection levels in most regions of Neolithic Europe. Our research shows that by AD 1200, lactase persistence frequency had risen to over 70% in this community in western Central Europe. Given that lactase persistence genotype frequency in present-day Germany and Austria is estimated at 71-80%, our results suggest that genetic lactase persistence likely reached modern levels before the historic population declines associated with the Black Death, thus excluding plague-associated evolutionary forces in the rise of lactase persistence in this region. This new evidence sheds light on the dynamic evolutionary histo