Polyomaviruses are a family of DNA tumor viruses that are known to infect mammals and birds. To investigate the deeper evolutionary history of the family, we used a combination of viral metagenomics, bioinformatics, and structural modeling approaches to identify and characterize polyomavirus sequences associated with fish and arthropods. Analyses drawing upon the divergent new sequences indicate that polyomaviruses have been gradually co-evolving with their animal hosts for at least half a billion years. Phylogenetic analyses of individual polyomavirus genes suggest that some modern polyomavirus species arose after ancient recombination events involving distantly related polyomavirus lineages. The improved evolutionary model provides a useful platform for developing a more accurate taxonomic classification system for the viral family Polyomaviridae.

While microbial communities in the human body (microbiota) are now commonly associated with health and disease in industrialised populations, we know very little about how these communities co-evolved and changed with humans throughout history and deep prehistory. We can now examine these communities by sequencing ancient DNA preserved within calcified dental plaque (calculus), providing insights into the origins of disease and their links to human history. Here, we examine ancient DNA preserved within dental calculus samples and their associations with two major cultural periods in Japan: the Jomon period hunter-gatherers approximately 3000 years before present (BP) and the Edo period agriculturalists 400-150 BP. We investigate how human oral microbiomes have changed in Japan through time and explore the presence of microorganisms associated with oral diseases (e.g. periodontal disease, dental caries) in ancient Japanese populations. Finally, we explore oral microbial strain diversity and its potential links to ancient demography in ancient Japan by performing phylogenomic analysis of a widely conserved oral species-Anaerolineaceae oral taxon 439. This research represents, to our knowledge, the first study of ancient oral microbiomes from Japan and demonstrates that the analysis of ancient dental calculus can provide key information about the origin of non-infectious disease and its deep roots with human demography. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.

Saber-toothed cats (Machairodontinae) are among the most widely recognized representatives of the now largely extinct Pleistocene megafauna. However, many aspects of their ecology, evolution, and extinction remain uncertain. Although ancient-DNA studies have led to huge advances in our knowledge of these aspects of many other megafauna species (e.g., mammoths and cave bears), relatively few ancient-DNA studies have focused on saber-toothed cats [1-3], and they have been restricted to short fragments of mitochondrial DNA. Here we investigate the evolutionary history of two lineages of saber-toothed cats (Smilodon and Homotherium) in relation to living carnivores and find that the Machairodontinae form a well-supported clade that is distinct from all living felids. We present partial mitochondrial genomes from one S. populator sample and three Homotherium sp. samples, including the only Late Pleistocene Homotherium sample from Eurasia [4]. We confirm the identification of the unique Late Pleistocene European fossil through ancient-DNA analyses, thus strengthening the evidence that Homotherium occurred in Europe over 200,000 years later than previously believed. This in turn forces a re-evaluation of its demography and extinction dynamics. Within the Machairodontinae, we find a deep divergence between Smilodon and Homotherium (∼18 million years) but limited diversity between the American and European Homotherium specimens. The genetic data support the hypothesis that all Late Pleistocene (or post-Villafrancian) Homotherium should be considered a single species, H. latidens, which was previously proposed based on morphological data [5, 6].

The Neolithic and Bronze Ages were highly transformative periods for the genetic history of Europe but for the Aegean-a region fundamental to Europe's prehistory-the biological dimensions of cultural transitions have been elucidated only to a limited extent so far. We have analysed newly generated genome-wide data from 102 ancient individuals from Crete, the Greek mainland and the Aegean Islands, spanning from the Neolithic to the Iron Age. We found that the early farmers from Crete shared the same ancestry as other contemporaneous Neolithic Aegeans. In contrast, the end of the Neolithic period and the following Early Bronze Age were marked by 'eastern' gene flow, which was predominantly of Anatolian origin in Crete. Confirming previous findings for additional Central/Eastern European ancestry in the Greek mainland by the Middle Bronze Age, we additionally show that such genetic signatures appeared in Crete gradually from the seventeenth to twelfth centuries BC, a period when the influence of the mainland over the island intensified. Biological and cultural connectedness within the Aegean is also supported by the finding of consanguineous endogamy practiced at high frequencies, unprecedented in the global ancient DNA record. Our results highlight the potential of archaeogenomic approaches in the Aegean for unravelling the interplay of genetic admixture, marital and other cultural practices.

Since the late eighteenth century, fossils of bizarre extinct creatures have been described from the Americas, revealing a previously unimagined chapter in the history of mammals. The most bizarre of these are the 'native' South American ungulates thought to represent a group of mammals that evolved in relative isolation on South America, but with an uncertain affinity to any particular placental lineage. Many authors have considered them descended from Laurasian 'condylarths', which also includes the probable ancestors of perissodactyls and artiodactyls, whereas others have placed them either closer to the uniquely South American xenarthrans (anteaters, armadillos and sloths) or the basal afrotherians (e.g. elephants and hyraxes). These hypotheses have been debated owing to conflicting morphological characteristics and the hitherto inability to retrieve molecular information. Of the 'native' South American mammals, only the toxodonts and litopterns persisted until the Late Pleistocene-Early Holocene. Owing to known difficulties in retrieving ancient DNA (aDNA) from specimens from warm climates, this research presents a molecular phylogeny for both Macrauchenia patachonica (Litopterna) and Toxodon platensis (Notoungulata) recovered using proteomics-based (liquid chromatography-tandem mass spectrometry) sequencing analyses of bone collagen. The results place both taxa in a clade that is monophyletic with the perissodactyls, which today are represented by horses, rhinoceroses and tapirs.

Archaeogenomic studies have largely elucidated human population history in West Eurasia during the Stone Age. However, despite being a broad geographical region of significant cultural and linguistic diversity, little is known about the population history in North Asia. We present complete mitochondrial genome sequences together with stable isotope data for 41 serially sampled ancient individuals from North Asia, dated between c.13,790 BP and c.1,380 BP extending from the Palaeolithic to the Iron Age. Analyses of mitochondrial DNA sequences and haplogroup data of these individuals revealed the highest genetic affinity to present-day North Asian populations of the same geographical region suggesting a possible long-term maternal genetic continuity in the region. We observed a decrease in genetic diversity over time and a reduction of maternal effective population size (Ne) approximately seven thousand years before present. Coalescent simulations were consistent with genetic continuity between present day individuals and individuals dating to 7,000 BP, 4,800 BP or 3,000 BP. Meanwhile, genetic differences observed between 7,000 BP and 3,000 BP as well as between 4,800 BP and 3,000 BP were inconsistent with genetic drift alone, suggesting gene flow into the region from distant gene pools or structure within the population. These results indicate that despite some level of continuity between ancient groups and present-day populations, the region exhibits a complex demographic history during the Holocene.

The RB-E2F pathway is conserved in most eukaryotic lineages, including animals and plants. E2F and RB family proteins perform crucial functions in cycle controlling, differentiation, development and apoptosis. However, there are two kinds of E2Fs (repressive E2Fs and active E2Fs) and three RB family members in human. Till now, the detail evolutionary history of these protein families and how RB-E2F pathway evolved in different organisms remain poorly explored.

As viral genomic imprints in host genomes, endogenous viral elements (EVEs) shed light on the deep evolutionary history of viruses, ancestral host ranges, and ancient viral-host interactions. In addition, they may provide crucial information for calibrating viral evolutionary timescales. In this study, we conducted a comprehensive in silico screening of a large data set of available mammalian genomes for EVEs deriving from members of the viral family Flaviviridae, an important group of viruses including well-known human pathogens, such as Zika, dengue, or hepatitis C viruses. We identified two novel pestivirus-like EVEs in the reference genome of the Indochinese shrew (Crocidura indochinensis). Homologs of these novel EVEs were subsequently detected in vivo by molecular detection and sequencing in 27 shrew species, including 26 species representing a wide distribution within the Crocidurinae subfamily and one in the Soricinae subfamily on different continents. Based on this wide distribution, we estimate that the integration event occurred before the last common ancestor of the subfamily, about 10.8 million years ago, attesting to an ancient origin of pestiviruses and Flaviviridae in general. Moreover, we provide the first description of Flaviviridae-derived EVEs in mammals even though the family encompasses numerous mammal-infecting members. This also suggests that shrews were past and perhaps also current natural reservoirs of pestiviruses. Taken together, our results expand the current known Pestivirus host range and provide novel insight into the ancient evolutionary history of pestiviruses and the Flaviviridae family in general.

Only five species of the once-diverse Rhinocerotidae remain, making the reconstruction of their evolutionary history a challenge to biologists since Darwin. We sequenced genomes from five rhinoceros species (three extinct and two living), which we compared to existing data from the remaining three living species and a range of outgroups. We identify an early divergence between extant African and Eurasian lineages, resolving a key debate regarding the phylogeny of extant rhinoceroses. This early Miocene (∼16 million years ago [mya]) split post-dates the land bridge formation between the Afro-Arabian and Eurasian landmasses. Our analyses also show that while rhinoceros genomes in general exhibit low levels of genome-wide diversity, heterozygosity is lowest and inbreeding is highest in the modern species. These results suggest that while low genetic diversity is a long-term feature of the family, it has been particularly exacerbated recently, likely reflecting recent anthropogenic-driven population declines.

Ibiza was permanently settled around the 7th century BCE by founders arriving from west Phoenicia. The founding population grew significantly and reached its height during the 4th century BCE. We obtained nine complete mitochondrial genomes from skeletal remains from two Punic necropoli in Ibiza and a Bronze Age site from Formentara. We also obtained low coverage (0.47X average depth) of the genome of one individual, directly dated to 361-178 cal BCE, from the Cas Molí site on Ibiza. We analysed and compared ancient DNA results with 18 new mitochondrial genomes from modern Ibizans to determine the ancestry of the founders of Ibiza. The mitochondrial results indicate a predominantly recent European maternal ancestry for the current Ibizan population while the whole genome data suggest a significant Eastern Mediterranean component. Our mitochondrial results suggest a genetic discontinuity between the early Phoenician settlers and the island's modern inhabitants. Our data, while limited, suggest that the Eastern or North African influence in the Punic population of Ibiza was primarily male dominated.

Study of parallel (or convergent) phenotypic evolution can provide important insights into processes driving sympatric, ecologically-mediated divergence and speciation, as ecotype pairs may provide a biological replicate of the underlying signals and mechanisms. Here, we provide evidence for a selective sweep creating an island of divergence associated with reproductive behavior in sockeye salmon (Oncorhynchus nerka), identifying a series of linked single nucleotide polymorphisms across a ~22,733 basepair region spanning the leucine-rich repeat-containing protein 9 gene exhibiting signatures of divergent selection associated with stream- and shore-spawning in both anadromous and resident forms across their pan-Pacific distribution. This divergence likely occurred ~3.8 Mya (95% HPD = 2.1-6.03 Mya), after sockeye separated from pink (O. gorbuscha) and chum (O. keta) salmon, but prior to the Pleistocene glaciations. Our results suggest recurrent evolution of reproductive ecotypes across the native range of O. nerka is at least partially associated with divergent selection of pre-existing genetic variation within or linked to this region. As sockeye salmon are unique among Pacific salmonids in their flexibility to spawn in lake-shore benthic environments, this region provides great promise for continued investigation of the genomic basis of O. nerka life history evolution, and, more broadly, for increasing our understanding of the heritable basis of adaptation of complex traits in novel environments.

The human N-acetyltransferase genes NAT1 and NAT2 encode two phase-II enzymes that metabolize various drugs and carcinogens. Functional variability at these genes has been associated with adverse drug reactions and cancer susceptibility. Mutations in NAT2 leading to the so-called slow-acetylation phenotype reach high frequencies worldwide, which questions the significance of altered acetylation in human adaptation. To investigate the role of population history and natural selection in shaping NATs variation, we characterized genetic diversity through the resequencing and genotyping of NAT1, NAT2, and the pseudogene NATP in a collection of 13 different populations with distinct ethnic backgrounds and demographic pasts. This combined study design allowed us to define a detailed map of linkage disequilibrium of the NATs region as well as to perform a number of sequence-based neutrality tests and the long-range haplotype (LRH) test. Our data revealed distinctive patterns of variability for the two genes: the reduced diversity observed at NAT1 is consistent with the action of purifying selection, whereas NAT2 functional variation contributes to high levels of diversity. In addition, the LRH test identified a particular NAT2 haplotype (NAT2*5B) under recent positive selection in western/central Eurasians. This haplotype harbors the mutation 341T-->C and encodes the "slowest-acetylator" NAT2 enzyme, suggesting a general selective advantage for the slow-acetylator phenotype. Interestingly, the NAT2*5B haplotype, which seems to have conferred a selective advantage during the past approximately 6,500 years, exhibits today the strongest association with susceptibility to bladder cancer and adverse drug reactions. On the whole, the patterns observed for NAT2 well illustrate how geographically and temporally fluctuating xenobiotic environments may have influenced not only our genome variability but also our present-day susceptibility to disease.

Rapa Nui is one of the most remote islands in the world. As a young island, its biota is a consequence of both natural dispersals over the last ~1 million years and recent human introductions. It therefore provides an opportunity to study a unique community assemblage. Here, we extract DNA from museum-preserved and newly field-collected spiders from the genus Tetragnatha to explore their history on Rapa Nui. Using an optimized protocol to recover ancient DNA from museum-preserved spiders, we sequence and assemble partial mitochondrial genomes from nine Tetragnatha species, two of which were found on Rapa Nui, and estimate the evolutionary relationships between these and other Tetragnatha species. Our phylogeny shows that the two Rapa Nui species are not closely related. One, the possibly extinct, T. paschae, is nested within a circumtropical species complex (T. nitens), and the other (Tetragnatha sp. Rapa Nui) appears to be a recent human introduction. Our results highlight the power of ancient DNA approaches in identifying cryptic and rare species, which can contribute to our understanding of the global distribution of biodiversity in all taxonomic lineages.

Goats are one of the most widespread farmed animals across the world; however, their migration route to East Asia and local evolutionary history remain poorly understood. Here, we sequenced 27 ancient Chinese goat genomes dating from the Late Neolithic period to the Iron Age. We found close genetic affinities between ancient and modern Chinese goats, demonstrating their genetic continuity. We found that Chinese goats originated from the eastern regions around the Fertile Crescent, and we estimated that the ancestors of Chinese goats diverged from this population in the Chalcolithic period. Modern Chinese goats were divided into a northern and a southern group, coinciding with the most prominent climatic division in China, and two genes related to hair follicle development, FGF5 and EDA2R, were highly divergent between these populations. We identified a likely causal de novo deletion near FGF5 in northern Chinese goats that increased to high frequency over time, whereas EDA2R harbored standing variation dating to the Neolithic. Our findings add to our understanding of the genetic composition and local evolutionary process of Chinese goats.

Prior to human settlement 700 years ago New Zealand had no terrestrial mammals--apart from three species of bats--instead, approximately 250 avian species dominated the ecosystem. At the top of the food chain was the extinct Haast's eagle, Harpagornis moorei. H. moorei (10-15 kg; 2-3 m wingspan) was 30%-40% heavier than the largest extant eagle (the harpy eagle, Harpia harpyja), and hunted moa up to 15 times its weight. In a dramatic example of morphological plasticity and rapid size increase, we show that the H. moorei was very closely related to one of the world's smallest extant eagles, which is one-tenth its mass. This spectacular evolutionary change illustrates the potential speed of size alteration within lineages of vertebrates, especially in island ecosystems.

Although simian foamy viruses (SFV) are the only exogenous retroviruses to infect New World monkeys (NWMs), little is known about their evolutionary history and epidemiology. Previous reports show distinct SFVs among NWMs but were limited to small numbers of captive or wild monkeys from five (Cebus, Saimiri, Ateles, Alouatta, and Callithrix) of the 15 NWM genera. Other studies also used only PCR testing or serological assays with limited validation and may have missed infection in some species. We developed and validated new serological and PCR assays to determine the prevalence of SFV in blood specimens from a large number of captive NWMs in the US (n = 274) and in captive and wild-caught NWMs (n = 236) in Peruvian zoos, rescue centers, and illegal trade markets. Phylogenetic and co-speciation reconciliation analyses of new SFV polymerase (pol) and host mitochondrial cytochrome B sequences, were performed to infer SFV and host co-evolutionary histories.

Parchment represents an invaluable cultural reservoir. Retrieving an additional layer of information from these abundant, dated livestock-skins via the use of ancient DNA (aDNA) sequencing has been mooted by a number of researchers. However, prior PCR-based work has indicated that this may be challenged by cross-individual and cross-species contamination, perhaps from the bulk parchment preparation process. Here we apply next generation sequencing to two parchments of seventeenth and eighteenth century northern English provenance. Following alignment to the published sheep, goat, cow and human genomes, it is clear that the only genome displaying substantial unique homology is sheep and this species identification is confirmed by collagen peptide mass spectrometry. Only 4% of sequence reads align preferentially to a different species indicating low contamination across species. Moreover, mitochondrial DNA sequences suggest an upper bound of contamination at 5%. Over 45% of reads aligned to the sheep genome, and even this limited sequencing exercise yield 9 and 7% of each sampled sheep genome post filtering, allowing the mapping of genetic affinity to modern British sheep breeds. We conclude that parchment represents an excellent substrate for genomic analyses of historical livestock.

The Scythians were a multitude of horse-warrior nomad cultures dwelling in the Eurasian steppe during the first millennium BCE. Because of the lack of first-hand written records, little is known about the origins and relations among the different cultures. To address these questions, we produced genome-wide data for 111 ancient individuals retrieved from 39 archaeological sites from the first millennia BCE and CE across the Central Asian Steppe. We uncovered major admixture events in the Late Bronze Age forming the genetic substratum for two main Iron Age gene-pools emerging around the Altai and the Urals respectively. Their demise was mirrored by new genetic turnovers, linked to the spread of the eastern nomad empires in the first centuries CE. Compared to the high genetic heterogeneity of the past, the homogenization of the present-day Kazakhs gene pool is notable, likely a result of 400 years of strict exogamous social rules.

Ribonuclease P is an ancient endonuclease that cleaves precursor tRNA and generally consists of a catalytic RNA subunit (RPR) and one or more proteins (RPPs). It represents an important macromolecular complex and model system that is universally distributed in life. Its putative origins have inspired fundamental hypotheses, including the proposal of an ancient RNA world.

The peptidyl transferase center (PTC) is the catalytic center of the ribosome and forms part of the 23S ribosomal RNA. The PTC has been recognized as the earliest ribosomal part and its origins embodied the First Universal Common Ancestor (FUCA). The PTC is frequently assumed to be highly conserved along all living beings. In this work, we posed the following questions: (i) How many 100% conserved bases can be found in the PTC? (ii) Is it possible to identify clusters of informationally linked nucleotides along its sequence? (iii) Can we propose how the PTC was formed? (iv) How does sequence conservation reflect on the secondary and tertiary structures of the PTC? Aiming to answer these questions, all available complete sequences of 23S ribosomal RNA from Bacteria and Archaea deposited on GenBank database were downloaded. Using a sequence bait of 179 bp from the PTC of Thermus termophilus, we performed an optimum pairwise alignment to retrieve the PTC region from 1424 filtered 23S rRNA sequences. These PTC sequences were multiply aligned, and the conserved regions were assigned and observed along the primary, secondary, and tertiary structures. The PTC structure was observed to be more highly conserved close to the adenine located at the catalytical site. Clusters of interrelated, co-evolving nucleotides reinforce previous assumptions that the PTC was formed by the concatenation of proto-tRNAs and important residues responsible for its assembly were identified. The observed sequence variation does not seem to significantly affect the 3D structure of the PTC ribozyme.