Correlating the Ancient Maya and Modern European Calendars with High-Precision AMS 14C Dating

The reasons for the development and collapse of Maya civilization remain controversial and historical events carved on stone monuments throughout this region provide a remarkable source of data about the rise and fall of these complex polities. Use of these records depends on correlating the Maya and European calendars so that they can be compared with climate and environmental datasets. Correlation constants can vary up to 1000 years and remain controversial. We report a series of high-resolution AMS C-14 dates on a wooden lintel collected from the Classic Period city of Tikal bearing Maya calendar dates. The radiocarbon dates were calibrated using a Bayesian statistical model and indicate that the dates were carved on the lintel between AD 658-696. This strongly supports the Goodman-Martinez-Thompson (GMT) correlation and the hypothesis that climate change played an important role in the development and demise of this complex civilization.

Description of an ancient social bee trapped in amber using diagnostic radioentomology

The application of non-invasive imaging technologies using X-radiation (diagnostic radioentomology, ‘DR’) is demonstrated for the study of amber-entombed social bees. Here, we examine the external and internal morphology of an Early Miocene (Burdigalian) stingless bee (Apinae: Meliponini) from the Dominican Republic using non-destructive X-ray microtomography analysis. The study permits the accurate reconstruction of features otherwise obscured or impossible to visualize without destroying the sample and allows diagnosis of the specimen as a new species, Proplebeia adbita Greco and Engel.

Comparison against 186 canid whole genome sequences reveals survival strategies of an ancient clonally transmissible canine tumor.

Canine transmissible venereal tumor (CTVT) is a parasitic cancer clone that has propagated for thousands of years via sexual transfer of malignant cells. Little is understood about the mechanisms that converted an ancient tumor into the world's oldest known continuously propagating somatic cell lineage. We created the largest existing catalog of canine genome-wide variation and compared it against two CTVT genome sequences, thereby separating alleles derived from the founder's genome from somatic drivers of clonal transmissibility. We show that CTVT has undergone continuous adaptation to its transmissible allograft niche, with overlapping mutations at every step of immunosurveillance, particularly self-antigen presentation and apoptosis. We also identified chronologically early somatic mutations in oncogenesis- and immune-related genes that may represent key initiators of clonal transmissibility. Thus, we provide the first insights into the specific genomic aberrations that underlie CTVT's dogged perseverance in canids around the world.

Ancient History as a Means of Transforming Colonial India in the Late-Eighteenth and Early-Nineteenth Centuries

This article focuses on the studies and discourses of mostly British scholars of the early colonial period belonging to two schools of thought. It shows how the studies of both schools – European orientalism and utilitarianism – were intricately connected to the political development of the emerging British paramountcy over the South Asian sub-continent, as both were looking for means of establishing and/or strengthening colonial rule. Nevertheless, the debate was not just a continuation of discussions in Europe. Whereas the ideas of the European Enlightenment had some influence, the transformation of the Mughal Empire and especially the idea of a decline of Muslim rule offered ample opportunities for understanding the early history of India either as some sort of “Golden Age,” as the orientalists and their indigenous supporters did, or as something static and degenerate, as the utilitarians did, and from which the population of sub-continent had to be saved by colonial rule and colonial values. Fearing the spread of the ideas of the French Revolution, the first group of British scholars sought to persuade the native elites of South Asia to take the lessons of their past for the future development of their homeland. Just as the classicists back in Europe, these scholars were convinced that large-scale explanations of the past could also teach political and moral lessons for the present although it was important to deal with the distant past in an empirical manner. The utilitarians on the other hand believed that India had to be saved from its own depravity through the English language and Western values, which amounted to nothing less than the modern transformation of the true Classical Age.

Association between variants of the leptin receptor gene (LEPR) and overweight: a systematic review and an analysis of the CoLaus study

Background Three non-synonymous single nucleotide polymorphisms (Q223R, K109R and K656N) of the leptin receptor gene (LEPR) have been tested for association with obesity-related outcomes in multiple studies, showing inconclusive results. We performed a systematic review and meta-analysis on the association of the three LEPR variants with BMI. In addition, we analysed 15 SNPs within the LEPR gene in the CoLaus study, assessing the interaction of the variants with sex. Methodology/Principal Findings We searched electronic databases, including population-based studies that investigated the association between LEPR variants Q223R, K109R and K656N and obesity- related phenotypes in healthy, unrelated subjects. We furthermore performed meta-analyses of the genotype and allele frequencies in case-control studies. Results were stratified by SNP and by potential effect modifiers. CoLaus data were analysed by logistic and linear regressions and tested for interaction with sex. The meta-analysis of published data did not show an overall association between any of the tested LEPR variants and overweight. However, the choice of a BMI cut-off value to distinguish cases from controls was crucial to explain heterogeneity in Q223R. Differences in allele frequencies across ethnic groups are compatible with natural selection of derived alleles in Q223R and K109R and of the ancient allele in K656N in Asians. In CoLaus, the rs10128072, rs3790438 and rs3790437 variants showed interaction with sex for their association with overweight, waist circumference and fat mass in linear regressions. Conclusions Our systematic review and analysis of primary data from the CoLaus study did not show an overall association between LEPR SNPs and overweight. Most studies were underpowered to detect small effect sizes. A potential effect modification by sex, population stratification, as well as the role of natural selection should be addressed in future genetic association studies.