OBJECTIVE:This paper aims to provide a quantitative estimation of the representation of diseases defined as rare today in the bioarchaeological literature and to outline the reasons for this.MATERIALS:A 45-year bibliometric study of publications in seven bioarchaeological journals, along with two journals and editorial groups of broader scientific focus.METHODS:Analyses of distribution patterns of the search hits and diachronic trends for achondroplasia, autosomal-dominant osteopetrosis, osteogenesis imperfecta, and osteopoikilosis, compared to those for tuberculosis as control measure of coverage.RESULTS:Studies of ancient rare diseases (ARD) are mostly published as case reports in specialized journals and their number did not benefit from the introduction of biomolecular studies. The higher frequency of cases of achondroplasia suggests that not all rare diseases are equally under-represented.CONCLUSIONS:Rare diseases are still largely under-represented in bioarchaeological literature. Their marginality likely results from a combination of taphonomic, methodological and public visibility factors.SIGNIFICANCE:This article is the first attempt to provide a quantitative assessment of the under-representation of ARD and to outline the factors behind it.LIMITATIONS:Rare diseases are an etiologically heterogeneous group. The number of surveyed journals and articles, as well as targeted diseases might be limiting factors.SUGGESTIONS FOR FURTHER RESEARCH:Increasing collection and dissemination of data on ARD; opening a wide-ranging debate on their definition; implementation of biomolecular studies.

The oral microbiome plays key roles in human biology, health, and disease, but little is known about the global diversity, variation, or evolution of this microbial community. To better understand the evolution and changing ecology of the human oral microbiome, we analyzed 124 dental biofilm metagenomes from humans, including Neanderthals and Late Pleistocene to present-day modern humans, chimpanzees, and gorillas, as well as New World howler monkeys for comparison. We find that a core microbiome of primarily biofilm structural taxa has been maintained throughout African hominid evolution, and these microbial groups are also shared with howler monkeys, suggesting that they have been important oral members since before the catarrhine-platyrrhine split ca. 40 Mya. However, community structure and individual microbial phylogenies do not closely reflect host relationships, and the dental biofilms of Homo and chimpanzees are distinguished by major taxonomic and functional differences. Reconstructing oral metagenomes from up to 100 thousand years ago, we show that the microbial profiles of both Neanderthals and modern humans are highly similar, sharing functional adaptations in nutrient metabolism. These include an apparent Homo-specific acquisition of salivary amylase-binding capability by oral streptococci, suggesting microbial coadaptation with host diet. We additionally find evidence of shared genetic diversity in the oral bacteria of Neanderthal and Upper Paleolithic modern humans that is not observed in later modern human populations. Differences in the oral microbiomes of African hominids provide insights into human evolution, the ancestral state of the human microbiome, and a temporal framework for understanding microbial health and disease.

Egypt, located on the isthmus of Africa, is an ideal region to study historical population dynamics due to its geographic location and documented interactions with ancient civilizations in Africa, Asia and Europe. Particularly, in the first millennium BCE Egypt endured foreign domination leading to growing numbers of foreigners living within its borders possibly contributing genetically to the local population. Here we present 90 mitochondrial genomes as well as genome-wide data sets from three individuals obtained from Egyptian mummies. The samples recovered from Middle Egypt span around 1,300 years of ancient Egyptian history from the New Kingdom to the Roman Period. Our analyses reveal that ancient Egyptians shared more ancestry with Near Easterners than present-day Egyptians, who received additional sub-Saharan admixture in more recent times. This analysis establishes ancient Egyptian mummies as a genetic source to study ancient human history and offers the perspective of deciphering Egypt's past at a genome-wide level.