RESUMO
Palaeoparasitology investigates parasitological infections in animals and humans of past distance by examining biological remains. Palaeofaeces (or coprolites) are biological remains that provide valuable information on the disease, diet, and population movements in ancient times. Today, advances in detecting ancient DNA have cast light on dark corners that microscopy could never reach. The archaeological site of the Chehrabad salt mine of Achaemenid (550-330 BC) and Sassanid (third-seventh century AD) provides remains of various biotic and abiotic samples, including animal coprolites, for multidisciplinary studies. In the present work, we investigated coprolites for helminth eggs and larvae by microscopy and traced their biological agents' DNA by Next Generation Sequencing. Our results revealed various helminths, including Taenia asiatica, the species introduced in the 1990s. Implementing advanced modern molecular techniques like NGS gives a paramount view of pathogenic agents in space and time.
Assuntos
Helmintos , Taenia , Animais , DNA Antigo , Genômica , Helmintos/genética , História Antiga , Humanos , Irã (Geográfico) , Taenia/genéticaRESUMO
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.
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DNA , Preservação Biológica , DNA/genética , Fixadores , Humanos , Preservação Biológica/métodos , Estudos Retrospectivos , Análise de Sequência de DNA/métodosRESUMO
Ancient Egyptian remains have been of interest for anthropological research for decades. Despite many investigations, the ritual vessels for the internal organs removed during body preparation-liver, lungs, stomach, and intestines, of Egyptian mummies are rarely used for palaeopathological or medical investigations. These artifacts, commonly referred to as canopic jars, are the perfect combination of cultural and biological material and present an untapped resource for both Egyptological and medical fields. Nevertheless, technical challenges associated with this archeological material have prevented the application of current ancient DNA techniques for both the characterization of human and pathogenic DNA. We present shotgun-sequenced metagenomic profiles and ancient DNA degradation patterns from multiple canopic jars sampled from several European museum collections and enumerate current limitations and possible solutions for the future analysis of similar material. This is the first-ever recorded evidence of ancient human DNA found in Ancient Egyptian canopic jars and the first associated metagenomic description of bacterial taxa in these funerary artifacts. OBJECTIVES: In this study, our objectives were to characterize the metagenomic profile of the Ancient Egyptian funerary vessels known as canopic jars to retrieve endogenous ancient human DNA, reconstruct ancient microbial communities, and identify possible pathogens that could shed light on disease states of individuals from the past. METHODS: We applied ancient DNA techniques on 140 canopic jars to extract DNA and generate whole-genome sequencing libraries for the analysis of both human and bacterial DNA. The samples were obtained from museum collections in Berlin (DE), Burgdorf (DE), Leiden (NE), Manchester (UK), Munich (DE), St. Gallen (CH), Turin (IT), and Zagreb (HR). RESULTS: Here we describe the first isolated DNA from the Egyptian artifacts that hold human viscera. No previous work was ever conducted on such material, which led to the first characterization of human DNA from Ancient Egyptian canopic jars and the profiling of the complex bacterial composition of this highly degraded, challenging, organic material. However, the DNA recovered was not of enough quality to confidently characterize bacterial taxa associated with infectious diseases, nor exclusive bacterial members of the human microbiome. DISCUSSION: In summary, we present the first genomic survey of the visceral content of Ancient Egyptian funerary artifacts and demonstrate the limitations of current molecular methods to analyze canopic jars, such as the incomplete history of the objects or the presence of uncharacterized compounds that can hamper the recovery of DNA. Our work highlights the main challenges and caveats when working with such complicated archeological material - and offers sampling recommendations for similarly complex future studies, such as incrementing the amount of starting material and sampling from the less exposed parts of the jar content. This is the first-ever recorded evidence of ancient human DNA found in Ancient Egyptian canopic jars, and our results open new avenues in the study of neglected archeological artifacts.
Assuntos
DNA Antigo , Múmias , Humanos , Egito , Múmias/patologia , Pulmão , Sequência de BasesRESUMO
Smallpox, caused by the variola virus (VARV), was a highly virulent disease with high mortality rates causing a major threat for global human health until its successful eradication in 1980. Despite previously published historic and modern VARV genomes, its past dissemination and diversity remain debated. To understand the evolutionary history of VARV with respect to historic and modern VARV genetic variation in Europe, we sequenced a VARV genome from a well-described eighteenth-century case from England (specimen P328). In our phylogenetic analysis, the new genome falls between the modern strains and another historic strain from Lithuania, supporting previous claims of larger diversity in early modern Europe compared to the twentieth century. Our analyses also resolve a previous controversy regarding the common ancestor between modern and historic strains by confirming a later date around the seventeenth century. Overall, our results point to the benefit of historic genomes for better resolution of past VARV diversity and highlight the value of such historic genomes from around the world to further understand the evolutionary history of smallpox as well as related diseases. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.
Assuntos
Evolução Molecular , Genoma Viral , Varíola/história , Vírus da Varíola/genética , Animais , Inglaterra , História do Século XVIII , Humanos , Lactente , Museus , FilogeniaRESUMO
Food and diet were class markers in 19th-century Ireland, which became evident as nearly 1 million people, primarily the poor and destitute, died as a consequence of the notorious Great Famine of 1845 to 1852. Famine took hold after a blight (Phytophthora infestans) destroyed virtually the only means of subsistence-the potato crop-for a significant proportion of the population. This study seeks to elucidate the variability of diet in mid-19th-century Ireland through microparticle and proteomic analysis of human dental calculus samples (n = 42) from victims of the famine. The samples derive from remains of people who died between August 1847 and March 1851 while receiving poor relief as inmates in the union workhouse in the city of Kilkenny (52°39' N, -7°15' W). The results corroborate the historical accounts of food provisions before and during the famine, with evidence of corn (maize), potato, and cereal starch granules from the microparticle analysis and milk protein from the proteomic analysis. Unexpectedly, there is also evidence of egg protein-a food source generally reserved only for export and the better-off social classes-which highlights the variability of the prefamine experience for those who died. Through historical contextualization, this study shows how the notoriously monotonous potato diet of the poor was opportunistically supplemented by other foodstuffs. While the Great Irish Famine was one of the worst subsistence crises in history, it was foremost a social disaster induced by the lack of access to food and not the lack of food availability.
Assuntos
Cálculos Dentários/química , Dieta/história , Fome Epidêmica/história , Pobreza/história , Adolescente , Adulto , Cálculos Dentários/história , Carboidratos da Dieta/análise , Carboidratos da Dieta/história , Proteínas Alimentares/análise , Proteínas Alimentares/história , Feminino , Fósseis , História do Século XIX , Humanos , Irlanda/epidemiologia , Masculino , Pessoa de Meia-Idade , Proteômica , Adulto JovemRESUMO
Recent paleogenomic studies have shown that migrations of Western steppe herders (WSH) beginning in the Eneolithic (ca. 3300-2700 BCE) profoundly transformed the genes and cultures of Europe and central Asia. Compared with Europe, however, the eastern extent of this WSH expansion is not well defined. Here we present genomic and proteomic data from 22 directly dated Late Bronze Age burials putatively associated with early pastoralism in northern Mongolia (ca. 1380-975 BCE). Genome-wide analysis reveals that they are largely descended from a population represented by Early Bronze Age hunter-gatherers in the Baikal region, with only a limited contribution (â¼7%) of WSH ancestry. At the same time, however, mass spectrometry analysis of dental calculus provides direct protein evidence of bovine, sheep, and goat milk consumption in seven of nine individuals. No individuals showed molecular evidence of lactase persistence, and only one individual exhibited evidence of >10% WSH ancestry, despite the presence of WSH populations in the nearby Altai-Sayan region for more than a millennium. Unlike the spread of Neolithic farming in Europe and the expansion of Bronze Age pastoralism on the Western steppe, our results indicate that ruminant dairy pastoralism was adopted on the Eastern steppe by local hunter-gatherers through a process of cultural transmission and minimal genetic exchange with outside groups.
Assuntos
Criação de Animais Domésticos/história , Genoma Humano , Dinâmica Populacional/história , Animais , Arqueologia , DNA Mitocondrial/genética , Europa (Continente) , Feminino , História Antiga , Migração Humana/história , Humanos , Masculino , MongóliaRESUMO
The reconstruction of ancient metagenomes from archaeological material, and their implication in human health and evolution, is one of the most recent advances in paleomicrobiological studies. However, as for all ancient DNA (aDNA) studies, environmental and laboratory contamination need to be specifically addressed. Here we attempted to reconstruct the tissue-specific metagenomes of a 42,000-year-old, permafrost-preserved woolly mammoth calf through shotgun high-throughput sequencing. We analyzed the taxonomic composition of all tissue samples together with environmental and non-template experimental controls and compared them to metagenomes obtained from permafrost and elephant fecal samples. Preliminary results suggested the presence of tissue-specific metagenomic signals. We identified bacterial species that were present in only one experimental sample, absent from controls, and consistent with the nature of the samples. However, we failed to further authenticate any of these signals and conclude that, even when experimental samples are distinct from environmental and laboratory controls, this does not necessarily indicate endogenous presence of ancient host-associated microbiomic signals.
RESUMO
Archaeological dental calculus has emerged as a rich source of ancient biomolecules, including proteins. Previous analyses of proteins extracted from ancient dental calculus revealed the presence of the dietary milk protein ß-lactoglobulin, providing direct evidence of dairy consumption in the archaeological record. However, the potential for calculus to preserve other food-related proteins has not yet been systematically explored. Here we analyse shotgun metaproteomic data from 100 archaeological dental calculus samples ranging from the Iron Age to the post-medieval period (eighth century BC to nineteenth century AD) in England, as well as 14 dental calculus samples from contemporary dental patients and recently deceased individuals, to characterize the range and extent of dietary proteins preserved in dental calculus. In addition to milk proteins, we detect proteomic evidence of foodstuffs such as cereals and plant products, as well as the digestive enzyme salivary amylase. We discuss the importance of optimized protein extraction methods, data analysis approaches and authentication strategies in the identification of dietary proteins from archaeological dental calculus. This study demonstrates that proteomic approaches can robustly identify foodstuffs in the archaeological record that are typically under-represented due to their poor macroscopic preservation.
Assuntos
Cálculos Dentários/química , Dieta/história , Proteoma , Arqueologia , DNA Antigo/análise , Inglaterra , História do Século XV , História do Século XVI , História do Século XVII , História do Século XVIII , História do Século XIX , História Antiga , História MedievalRESUMO
Fascioliasis is a highly pathogenic zoonotic disease caused by the liver trematodes Fasciola hepatica and F. gigantica. Within the multidisciplinary initiative against this disease, there is the aim of understanding how this disease reached a worldwide distribution, with important veterinary and medical repercussions, by elucidating the spreading steps followed by the two fasciolids from their paleobiogeograhical origins. Fasciola eggs were detected in paleofaeces of a donkey, probably the present-day endangered Persian onager Equus hemionus onager, found in the Chehrabad salt mine archaeological site, Zanjan province, northwestern Iran. The biological remains dated back to the Sassanid period, 224-651 AD. Egg characteristics allowed for their specific ascription to F. hepatica. The interest of this finding relies on the fact of being the first archaeological finding of Fasciola in Asia and the Near East. Moreover, it allows to reach many conclusions about historical, epidemiological and spreading aspects of the disease. The finding in Chehrabad indicates that, at that time, this fasciolid had already spread through the Zagros mountains eastward from the Fertile Crescent. In that region and in ancient Egypt, livestock domestication played a crucial role in facilitating the disease spread during the postdomestication period. Donkeys appear at present to be usually infected by fasciolids in countries of the Fertile Crescent - Ancient Egypt region or neighbouring that region, with prevalences from low to very high. The high pathogenicity and mortality induced by Fasciola in these equines should be considered as an additional potential factor among the causes of the extinctions of E. h. hemippus in Syria, E. h. hydruntinus in the Anatolia-Balkans area, E. h. onager in the Caucasus and maybe also its decline in Iran. Indeed, Eurasiatic wild asses were present in the region and neighbourhood of the Fertile Crescent when the domestication of the livestock reservoirs of Fasciola began.
Assuntos
Equidae/parasitologia , Fasciola hepatica/isolamento & purificação , Fasciolíase/veterinária , Animais , Fasciolíase/epidemiologia , Fasciolíase/história , Fasciolíase/parasitologia , História Antiga , História Medieval , Irã (Geográfico)/epidemiologiaRESUMO
OBJECTIVES: The island of Sardinia has one of the highest incidence rates of ß-thalassemia in Europe due to its long history of endemic malaria, which, according to historical records, was introduced around 2,600 years ago by the Punics and only became endemic around the Middle Ages. In particular, the cod39 mutation is responsible for more than 95% of all ß-thalassemia cases observed on the island. Debates surround the origin of the mutation. Some argue that its presence in the Western Mediterranean reflects the migration of people away from Sardinia, others that it reflects the colonization of the island by the Punics who might have carried the disease allele. The aim of this study was to investigate ß-globin mutations, including cod39, using ancient DNA (aDNA) analysis, to better understand the history and origin of ß-thalassemia and malaria in Sardinia. MATERIALS AND METHODS: PCR analysis followed by sequencing were used to investigate the presence of ß-thalassemia mutations in 19 individuals from three different Roman and Punic necropolises in Sardinia. RESULTS: The cod39 mutation was identified in one male individual buried in a necropolis from the Punic/Roman period. Further analyses have shown that his mitochondrial DNA (mtDNA) and Y-chromosome haplogroups were U5a and I2a1a1, respectively, indicating the individual was probably of Sardinian origin. CONCLUSIONS: This is the earliest documented case of ß-thalassemia in Sardinia to date. The presence of such a pathogenic mutation and its persistence until present day indicates that malaria was likely endemic on the island by the Roman period, earlier than the historical sources suggest.
Assuntos
Globinas beta/genética , Talassemia beta/genética , Talassemia beta/história , Antropologia Física , Cromossomos Humanos Y/genética , DNA Mitocondrial/análise , DNA Mitocondrial/genética , Doenças Endêmicas/história , Feminino , Haplótipos/genética , História Antiga , Humanos , Itália , Malária/história , Masculino , Mutação/genéticaRESUMO
The CCR5-Δ32 mutation present in European populations is among the most prominently debated cases of recent positive selection in humans. This allele, a 32-bp deletion that renders the T-cell CCR5 receptor nonfunctional, has important epidemiological and public health significance, as homozygous carriers are resistant to several HIV strains. However, although the function of this allele in preventing HIV infection is now well described, its human evolutionary origin is poorly understood. Initial attempts to determine the emergence of the CCR5-Δ32 allele pointed to selection during the 14th-century Black Death pandemic; however, subsequent analyses suggest that the allele rose in frequency more than 5,000 years ago, possibly through drift. Recently, three studies have identified populations predating the 14th century CE that are positive for the CCR5-Δ32 allele, supporting the claim for a more ancient origin. However, these studies also suggest poorly understood regional differences in the recent evolutionary history of the CCR5-Δ32 allele. Here a new hydrolysis-probe-based real-time PCR assay was designed to ascertain CCR5 allele frequency in 53 individuals from a 10th- to 12th-century CE church and convent complex in central Germany that predates outbreaks of the Black Death pandemic. High-confidence genotypes were obtained for 32 individuals, and results show that CCR5-Δ32 allele frequency has remained unchanged in this region of Central Europe over the last millennium, suggesting that there has been no strong positive selective pressure over this time period and confirming a more ancient origin for the allele.
Assuntos
DNA Antigo/análise , Frequência do Gene/genética , Receptores CCR5/genética , População Branca/genética , Cemitérios , Surtos de Doenças , Etnicidade/genética , Genótipo , Alemanha/etnologia , História Medieval , Homozigoto , Humanos , Peste/epidemiologia , Deleção de Sequência/genéticaRESUMO
Queen Nefertari, the favourite Royal Consort of Pharaoh Ramses II (Ancient Egypt, New Kingdom, 19th Dynasty c. 1250 BC) is famous for her beautifully decorated tomb in the Valley of the Queens. Her burial was plundered in ancient times yet still many objects were found broken in the debris when the tomb was excavated. Amongst the found objects was a pair of mummified legs. They came to the Egyptian Museum in Turin and are henceforth regarded as the remains of this famous Queen, although they were never scientifically investigated. The following multidisciplinary investigation is the first ever performed on those remains. The results (radiocarbon dating, anthropology, paleopathology, genetics, chemistry and Egyptology) all strongly speak in favour of an identification of the remains as Nefertari's, although different explanations-albeit less likely-are considered and discussed. The legs probably belong to a lady, a fully adult individual, of about 40 years of age. The materials used for embalming are consistent with Ramesside mummification traditions and indeed all objects within the tomb robustly support the burial as of Queen Nefertari.
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Embalsamamento/métodos , Perna (Membro)/anatomia & histologia , Múmias/história , Paleopatologia/métodos , Sequência de Bases , DNA Mitocondrial/genética , Antigo Egito , História Antiga , Humanos , Datação Radiométrica , Análise de Sequência de DNARESUMO
Archaeogenetics is the study of exploration of ancient DNA (aDNA) of more than 70 years old. It is an important part of the wider studies of many different areas of our past, including animal, plant and pathogen evolution and domestication events. Hereby, we address specifically the impact of research in archaeogenetics in the broader field of evolutionary medicine. Studies on ancient hominid genomes help to understand even modern health patterns. Human genetic microevolution, e.g. related to abilities of post-weaning milk consumption, and specifically genetic adaptation in disease susceptibility, e.g. towards malaria and other infectious diseases, are of the upmost importance in contributions of archeogenetics on the evolutionary understanding of human health and disease. With the increase in both the understanding of modern medical genetics and the ability to deep sequence ancient genetic information, the field of archaeogenetic evolutionary medicine is blossoming.
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Arqueologia , Evolução Molecular , Estudos de Associação Genética , Predisposição Genética para Doença , Interações Hospedeiro-Patógeno/genética , Animais , Arqueologia/métodos , DNA/genética , Meio Ambiente , Interação Gene-Ambiente , Estudos de Associação Genética/métodos , Genética Populacional , Genômica/métodos , HumanosRESUMO
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.
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Fragmentação do DNA , DNA Mitocondrial/genética , Adulto , Feminino , Humanos , Múmias , Músculo Esquelético , Reação em Cadeia da Polimerase , Pele , Cloreto de Sódio/química , Preservação de TecidoRESUMO
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 history of the European lactase persistence trait and its global cultural implications.
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Lactase/genética , Intolerância à Lactose/genética , Alelos , Animais , DNA Mitocondrial/genética , Evolução Molecular , Feminino , Frequência do Gene , Alemanha , História Medieval , Humanos , Intolerância à Lactose/história , Masculino , Leite , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNARESUMO
The use of ancient DNA in paleopathological studies of tuberculosis has largely been restricted to confirmation of disease identifications made by skeletal analysis; few attempts at obtaining genotype data from archaeological samples have been made because of the need to perform different PCRs for each genetic locus being studied in an ancient DNA extract. We used a next generation sequencing approach involving hybridization capture directed at specific polymorphic regions of the Mycobacterium tuberculosis genome to identify a detailed genotype for a historic strain of M. tuberculosis from an individual buried in the 19th century St. George's Crypt, Leeds, West Yorkshire, England. We obtained 664,500 sequencing by oligonucleotide ligation and detection (SOLiD) reads that mapped to the targeted regions of the M. tuberculosis genome; the coverage included 218 of 247 SNPs, 10 of 11 insertion/deletion regions, and the repeat elements IS1081 and IS6110. The accuracy of the SOLiD data was checked by conventional PCRs directed at 11 SNPs and two insertion/deletions. The data placed the historic strain of M. tuberculosis in a group that is uncommon today, but it is known to have been present in North America in the early 20th century. Our results show the use of hybridization capture followed by next generation sequencing as a means of obtaining detailed genotypes of ancient varieties of M. tuberculosis, potentially enabling meaningful comparisons between strains from different geographic locations and different periods in the past.
Assuntos
Mycobacterium tuberculosis/genética , Paleontologia , Técnicas de Tipagem Bacteriana , Sequência de Bases , Inglaterra , Feminino , Genoma Bacteriano/genética , Genótipo , Humanos , Dados de Sequência Molecular , Oligonucleotídeos/genética , Filogenia , Reação em Cadeia da Polimerase , Alinhamento de Sequência , Análise de Sequência de DNARESUMO
The major problems concerning ancient DNA studies are related to the amount of extractable DNA and the precautions needed to avoid contamination. From the very first step of the analyses, the DNA extraction, these problems must be confronted. There are several extraction methods available for DNA in ancient tissue; several of them are complicated and time consuming, and none of the methods have reached an acceptance level such that they are routinely used on a widespread basis. Here we investigate the efficiency of two methods, one based on magnetic separation of the targeted molecules, and one based on silica binding. The efficiency rate of these two on the material studied seems to be identical. The silica binding method has the benefit of relative simplicity, but the magnetic separation technique also has advantages. For example, it is possible to reuse the extract several times for different loci, and it is possible to concentrate all extracted DNA from one locus into one PCR.
Assuntos
DNA/análise , DNA/isolamento & purificação , Fósseis , História Antiga , Animais , Biotinilação , Osso e Ossos/química , Bovinos , DNA/química , Primers do DNA/metabolismo , Ácido Edético/química , Ácido Edético/farmacologia , Feminino , Magnetismo , Técnicas de Amplificação de Ácido Nucleico , Paleontologia , Reação em Cadeia da Polimerase , Dióxido de Silício/química , Dióxido de Silício/economia , Fatores de Tempo , Dente/químicaRESUMO
We present a method to distinguish authentic ancient DNA from contaminating DNA in a human bone. This is achieved by taking account of the spatial distribution of the various sequence families within the bone and the extent of degradation of the template DNAs, as revealed by the error content of the sequences. To demonstrate the veracity of the method, we handled two ancient human tibiae in order to contaminate them with modern DNA, and then subjected segments of the bones to various decontaminating treatments, including removal of the outer 1-2 mm, before extracting DNA, cloning, and obtaining a total of 107 mitochondrial DNA sequences. Sequences resulting from the deliberate contamination were located exclusively in the outer 1-2 mm of the bones, and only one of these 27 sequences contained an error that could be ascribed to DNA degradation. A second, much smaller set of relatively error-free sequences, which we ascribe to contamination during excavation or curation, was also located exclusively in the outer 1-2 mm. In contrast, a family of 72 sequences, displaying extensive degradation products but identifiable as haplogroup U5a1a, was distributed throughout one of the bones and represents the authentic ancient DNA content of this specimen.
Assuntos
Osso e Ossos/química , DNA/isolamento & purificação , Primers do DNA , Inglaterra , Fósseis , Grécia Antiga , História Antiga , Humanos , Tíbia/químicaRESUMO
The geographic situation of the Iberian Peninsula makes it a natural link between Europe and North Africa. However, it is a matter of debate to what extent African influences via the Straits Gibraltar have affected Iberia's prehistoric development. Because early African pastoralist communities were dedicated to cattle breeding, a possible means to detect prehistoric African-Iberian contacts might be to analyze the origin of cattle breeds on the Iberian Peninsula. Some contemporary Iberian cattle breeds show a mtDNA haplotype, T1, that is characteristic to African breeds, generally explained as being the result of the Muslim expansion of the 8th century A.D., and of modern imports. To test a possible earlier African influence, we analyzed mtDNA of Bronze Age cattle from the Portalón cave at the Atapuerca site in northern Spain. Although the majority of samples showed the haplotype T3 that dominates among European breeds of today, the T1 haplotype was found in one specimen radiocarbon dated 1800 calibrated years B.C. Accepting T1 as being of African origin, this result indicates prehistoric African-Iberian contacts and lends support to archaeological finds linking early African and Iberian cultures. We also found a wild ox haplotype in the Iberian Bronze Age sample, reflecting local hybridization or backcrossing or that aurochs were hunted by these farming cultures.