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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Archaeogenomics illuminates 4000 years of Northern European Short Tailed Sheep in the Baltic Sea region

Larsson, Martin January 2022 (has links)
Sheep were domesticated ~10 000 years ago from Asiatic Mouflon. They then spread to Europe via the migration of farming human populations and had reached Scandinavia by ~6000 years ago. Another migration of humans stemming from the Pontic-Caspian steppe reached Scandinavia around ~5000 years ago, possibly with new types of sheep. Ancient sheep have mostly been studied using mitochondrial DNA. The few examples to date that have applied genome wide sequencing have shown that modern northern European sheep are most closely related to ~9000-year-old Anatolian sheep. Northern European Short Tailed sheep are a group known for their “rustic” phenotype. Their visual appearance together with mitochondrial DNA studies has led to the hypothesis that these sheep are a relict of early migrations. In this study I present five new ancient domestic sheep genomes, from the islands Gotland and Åland in the Baltic Sea, covering the timespan ~4000-500 years ago. Most samples show exceptionally good preservation, with four having over 1x nuclear coverage, ranging up to 11.6x. I use these genomes together with two large panels of Eurasian genome wide SNPs, which includes the three Norther European Short Tailed breeds from these islands, Gotland- Gute-, and Åland sheep. I study how these ancient sheep relate to modern populations. I also evaluate their wool phenotype based on two genetic markers and find that these ancient sheep probably had medium-coarse wool fiber thickness. The results also show that sheep in the Baltic Sea area show a remarkable degree of continuity between 4000 and 500 years ago, and that these ancient sheep are closely related to modern breeds from the area, Åland sheep being the closest extant population.
52

A bear-y strong comeback: Investigating temporal genomic consequences of a recent demographic bottleneck in the Scandinavian brown bear

Lindahl, Amanda January 2023 (has links)
The Scandinavian brown bear went through a severe bottleneck due to human actions in the early 1900’s that reduced the population to low numbers. After protective measures were taken, the population recovered and today it consists of around 3000 individuals. Such loss of genetic variation can have long-lasting effects on population viability even as populations recover, and is therefore important to consider in the management and conservation of species. Previous studies investigating the genetic effects of the bottleneck based on genetic markers, such as microsatellites and mitochondrial DNA, have rendered inconclusive results. Here, whole-genome sequencing of historical and contemporary bears was used to estimate heterozygosity, inbreeding and mutational load in the pre- and post- bottleneck population. Surprisingly, a significant increase in heterozygosity was found in the contemporary population and no significant increase in inbreeding over time was found. However, mutational load was higher in the contemporary subpopulation in the south of Sweden compared to the subpopulation in the north, and the southern subpopulation seems to have lost unique genetic variation after the bottleneck. The results indicate that although the population was negatively affected by the bottleneck, a following increase in gene flow could have contributed to successful recovery of the population.
53

DNA from keratinous tissue. Part I: Hair and nail

Bengtsson, C.F., Olsen, M.E., Brandt, L.O., Bertelsen, M.F., Willerslev, E., Tobin, Desmond J., Wilson, Andrew S., Gilbert, M.T.P. January 2012 (has links)
No / Keratinous tissues such as nail, hair, horn, scales and feather have been used as a source of DNA for over 20 years. Particular benefits of such tissues include the ease with which they can be sampled, the relative stability of DNA in such tissues once sampled, and, in the context of ancient genetic analyses, the fact that sampling generally causes minimal visual damage to valuable specimens. Even when freshly sampled, however, the DNA quantity and quality in the fully keratinized parts of such tissues is extremely poor in comparison to other tissues such as blood and muscle – although little systematic research has been undertaken to characterize how such degradation may relate to sample source. In this review paper we present the current understanding of the quality and limitations of DNA in two key keratinous tissues, nail and hair. The findings indicate that although some fragments of nuclear and mitochondrial DNA appear to be present in almost all hair and nail samples, the quality of DNA, both in quantity and length of amplifiable DNA fragments, vary considerably not just by species, but by individual, and even within individual between hair types.
54

Multi-Proxy Characterisation of the Storegga Tsunami and Its Impact on the Early Holocene Landscapes of the Southern North Sea

Gaffney, Vincent L., Fitch, Simon, Bates, M., Ware, R.L., Kinnaird, T., Gearey, B., Hill, T., Telford, Richard, Batt, Catherine M., Stern, Ben, Whittaker, J., Davies, S., Ben Sharada, Mohammed, Everett, R., Cribdon, R., Kistler, L., Harris, Sam, Kearney, K., Walker, James, Muru, Merle, Hamilton, D., Law, M., Finlay, A., Bates, R., Allaby, R.G. 13 August 2020 (has links)
Yes / Doggerland was a landmass occupying an area currently covered by the North Sea until marine inundation took place during the mid-Holocene, ultimately separating the British landmass from the rest of Europe. The Storegga Event, which triggered a tsunami reflected in sediment deposits in the northern North Sea, northeast coastlines of the British Isles and across the North Atlantic, was a major event during this transgressive phase. The spatial extent of the Storegga tsunami however remains unconfirmed as, to date, no direct evidence for the event has been recovered from the southern North Sea. We present evidence of a tsunami deposit in the southern North Sea at the head of a palaeo-river system that has been identified using seismic survey. The evidence, based on lithostratigraphy, geochemical signatures, macro and microfossils and sedimentary ancient DNA (sedaDNA), supported by optical stimulated luminescence (OSL) and radiocarbon dating, suggests that these deposits were a result of the tsunami. Seismic identification of this stratum and analysis of adjacent cores showed diminished traces of the tsunami which was largely removed by subsequent erosional processes. Our results confirm previous modelling of the impact of the tsunami within this area of the southern North Sea, and also indicate that these effects were temporary, localized, and mitigated by the dense woodland and topography of the area. We conclude that clear physical remnants of the wave in these areas are likely to be restricted to now buried, palaeo-inland basins and incised river valley systems.
55

Archaeological dental calculus reveals patterns of dietary shifts related to the farming transition in Africa

Argueta Mejia, Ivany Jocelyne January 2023 (has links)
Archaeological dental calculus represents a depositional environment that entraps oral microbes, and debris of dietary, environmental, and cultural material that entered the mouth throughout the host’s life. Hence, they represent valuable archives of information about the host’s lifestyle, health, and environment. The aim of this study was to identify if the farming transition and its’ associated change in diet composition, may have influenced species composition in the oral cavity. To shed some light into the evolution of ancient oral microbiomes from Africa, 3 novel Iron Age dental calculus metagenomes together with a comparative dataset of 18 archaeological dental calculus metagenomes from North African Upper Palaeolithic, Later Stone Age, Iron Age, and 18th-19th century populations where analysed. Shotgun sequencing data was used to reconstruct 21 oral metagenomes from the past 15,000 years. This study found an oral microbiome that has been maintained from the Upper Palaeolithic (North Africa) to the 19th Century. However, closer examination to the relative abundance of three keystone species of the subgingival plaque, portray a chronological evolution that reflects that of its host during the major dietary and cultural transition that occurred during the farming revolution in the Iron Age.
56

Mammoth phylogeography south of the ice: large-scale sequencing of degraded DNA from temperate deposits

Enk, Jacob M. 04 1900 (has links)
<p>Mammoths (<em>Mammuthus</em>) have been studied extensively at the genetic level. However due to both taphonomic and technological limitations, only one of several late Pleistocene mammoth species, the woolly mammoth (<em>M. primigenius</em>), has been investigated. This limits our impression of mammoth population history to the the northern latitudes, just one of several environments in which mammoths lived and went extinct. It also obscures their evolutionary chronology, which prevents proper climatic and biogeographic contextualization of their history. Fortunately recent technological advances in high-throughput sequencing and targeted enrichment promise to expand Pleistocene faunal population phylogeography to non-permafrost, non-cave burial contexts. However the capacity and behavior of these combined technologies for characterizing ancient DNA is largely unexplored, preventing efficient and routine use for population-level studies. In this thesis I test and apply these technologies to remains of mammoth species from throughout North America. I first demonstrate their potential for poorly-preserved DNA, and then I evaluate their efficient application to large sample sets, as well as for capturing complete nuclear genomes. I then use these technologies to sequence dozens of mitochondrial genomes from Columbian (<em>M. columbi</em>)<em> </em>and other non-woolly mammoths, reconstructing their matrilineal phylogeography south of the ice. The revealed patterns not only imply a deep chronology for mammoth matrilineal diversity, but also that North American mammoth evolution was occurred via separate episodes of interbreeding between resident and invading populations, and between ecotypes. Overall the biological and methodological discoveries afforded by this body of work outline future research avenues on mammoth evolution, behavior, and extinction.</p> / Doctor of Philosophy (PhD)
57

Assessing Migration and Demographic Change in pre-Roman and Roman Period Southern Italy Using Whole-Mitochondrial DNA and Stable Isotope Analysis / The Biogeographic Origins of Iron Age Peucetians and Working-Class Romans From Southern Italy

Emery, Matthew 06 1900 (has links)
Assessing population diversity in southern Italy has traditionally relied on archaeological and historic evidence. Although informative, these lines of evidence do not establish specific instances of within lifetime mobility, nor track population diversity over time. In order to investigate the population structure of ancient South Italy I sequenced the mitochondrial DNA (mtDNA) from 15 Iron Age (7th – 4th c. BCE) and 30 Roman period (1st – 4th c. BCE) individuals buried at Iron Age Botromagno and Roman period Vagnari, in southern Italy, and analyzed δ18O and 87Sr/86Sr values from a subset of the Vagnari skeletal assemblage. Phylogenetic analysis of 15 Iron Age mtDNAs together with 231 mtDNAs spanning European prehistory suggest that southern Italian Iapygians share close genetic affinities to Neolithic populations from eastern Europe and the Near East. Population pairwise analysis of Iron Age, Roman, and mtDNA datasets spanning the pan-Mediterranean region (n=357), indicate that Roman maternal genetic diversity is more similar to Neolithic and Bronze Age populations from central Europe and the eastern Mediterranean, respectively, than to Iron Age Italians. Genetic distance between population age categories imply moderate mtDNA turnover and constant population size during the Roman conquest of South Italy in the 3rd century BCE. In order to determine the local versus non-local demographic at Vagnari, I measured the 87Sr/86Sr and 18O/16O of composition of 43 molars, and the 87Sr/86Sr composition of an additional 13 molars, and constructed a preliminary 87Sr/86Sr variation map of the Italian peninsula using disparate 87Sr/86Sr datasets. The relationship between 87Sr/86Sr and previously published δ18O data suggest a relatively low proportion of migrants lived at Vagnari (7%). This research is the first to generate whole-mitochondrial DNA sequences from Iron Age and Roman period necropoleis, and demonstrates the ability to gain valuable information from the integration of aDNA, stable isotope, archaeological and historic evidence. / Thesis / Doctor of Philosophy (PhD) / With biochemical information obtained from teeth, this study examines the population structure and geographic origins in two archaeological communities located in southern Italy. Analysis of classical remains has traditionally been the subject of historical and archaeological inquiry. However, new applications evaluate these population changes with integrated stable isotope and ancient DNA techniques. Overall, the biochemical results suggest that the pre-Roman communities harbor deep maternal ancestry originating from eastern Europe and the eastern Mediterannean. These results, when compared to the genetic diversity of Roman and broader Mediterranean populations, indicate that the Romans share closer genetic similarity with ancient Stone and Bronze Age communites from Europe and the eastern Mediterranean, than with the pre-Roman community studied here. Furthermore, tooth chemistry results indicate a predominantly local population buried in the Roman period cemetery.
58

Entwicklung neuer Markersysteme für die ancient DNA Analyse / Erweiterung des molekulargenetischen Zugangs zu kultur- und sozialgeschichtlichen Fragestellungen der Prähistorischen Anthropologie / Development of new marker systems for ancient DNA research / Extending the molecular approach to historico-cultural questions in Prehistoric Anthropology

Schmidt, Diane Manuela 30 June 2004 (has links)
No description available.
59

Etude des parentés génétiques dans les populations humaines anciennes : estimation de la fiabilité et de l'efficacité des méthodes d'analyse / Genetic kinship in ancient human populations : estimating the reliability and efficiency of analysis methods

Zvénigorosky-Durel, Vincent 13 November 2018 (has links)
L'étude des parentés génétiques permet à l'anthropologie d'identifier la place du sujet au sein des différentes structures dans lesquelles il évolue : l'individu est membre d'une famille biologique, d'un groupe social et d'une population. L'application des méthodes probabilistes classiques (établies pour répondre à des problématiques de médecine légale, comme la méthode des Likelihood Ratios (LR) ou " Rapports de vraisemblance ") aux données STR issues du matériel archéologique a permis la découverte de nombreux liens de parenté, qui ensemble constituent des généalogies parfois complexes. Notre pratique prolongée de ces méthodes nous a cependant amenés à identifier certaines limites de l'interprétation des données STR, en particulier dans les cas de parentés complexes, distantes ou consanguines, ou dans des populations isolées, méconnues ou disparues. Ce travail de thèse s'attache en premier lieu à quantifier la fiabilité et l'efficacité de la méthode des LR dans quatre situations : une population moderne avec une grande diversité allélique, une population moderne avec une faible diversité allélique, une population ancienne de grande taille et une population ancienne de petite taille. Les publications récentes font usage des marqueurs plus nombreux issus des nouvelles technologies de séquençage (NGS) pour mettre en place de nouvelles stratégies de détection des parentés, basées en particulier sur l'analyse des segments chromosomiques partagés par ascendance entre les individus (segments IBD). Ces méthodes ont rendu possible l'estimation plus fiable de probabilités de parenté dans le matériel ancien. Elles sont néanmoins inadaptées à certaines situations caractéristiques de la génétique des parentés archéologiques : elles ne sont pas conçues pour fonctionner avec une seule paire isolée d'individus et reposent, comme les méthodes classiques, sur l'estimation de la diversité allélique dans la population. Nous proposons donc une quantification de la fiabilité et de l'efficacité de la méthode des segments partagés à partir de données NGS, en s'attachant à déterminer la qualité des résultats dans les différentes situations qui correspondent à des tailles de population plus ou moins importantes et à une hétérogénéité plus ou moins grande de l'échantillonnage.[...] / The study of genetic kinship allows anthropology to identify the place of an individual within which they evolve: a biological family, a social group, a population. The application of classical probabilistic methods (that were established to solve cases in legal medicine, such as Likelihood Ratios, or LR) to STR data from archaeological material has permitted the discovery of numerous parental links which together constitute genealogies both simple and complex. Our continued practice of these methods has however led us to identify limits to the interpretation of STR data, especially in cases of complex, distant or inbred kinship. The first part of the present work is constituted by the estimation of the reliability and the efficacy of the LR method in four situations: a large modern population with significant allelic diversity, a large modern population with poor allelic diversity, a large ancient population and a small ancient population. Recent publications use the more numerous markers analysed using Next generation Sequencing (NGS) to implement new strategies in the detection of kinship, especially based on the analysis of chromosome segments shared due to common ancestry (IBD "Identity-by-Descent" segments). These methods have permitted the more reliable estimation of kinship probabilities in ancient material. They are nevertheless ill-suited to certain typical situations that are characteristic of ancient DNA studies: they were not conceived to function using single pairs of isolated individuals and they depend, like classical methods, on the estimation of allelic diversity in the population. We therefore propose the quantification of the reliability and efficiency of the IBD segment method using NGS data, focusing on the estimation of the quality of results in different situations with populations of different sizes and different sets of more or less heterogeneous samples.[...]
60

Pre-Columbian Population Dynamics and Cultural Development in South Coast Perú as Revealed by Analysis of Ancient DNA / Dinámica poblacional y desarrollo cultural prehispánicos en la costa sur del Perú: lo que revelan los análisis de ADN antiguo

Fehren-Schmitz, Lars 10 April 2018 (has links)
In this paper I report on a study whose principal aim is to understand the development and decline of the southern Peruvian Nasca culture in the upper Río Grande de Nasca drainage, and its cultural and biological affinities to the preceding Paracas culture. Ancient DNA analyses were conducted on over 300 pre-Columbian individuals from various cemeteries in southern Perú, from periods ranging from the Formative Period to the Middle Horizon. Our results show that the Nasca populations are close related to those of the preceding Paracas culture, and combined with archaeological data, suggest that the Nasca culture was autochthonous to the Río Grande drainage. Furthermore, one can observe how changes in socioeconomic complexity influence the genetic diversity. The pre-Columbian coastal populations of southern Perú differ significantly from both ancient highland and all present-day Peruvian populations. The genetic differentiation between the main cultural areas of western South America seems to fade with the Middle Horizon. / Se presenta aquí un estudio cuyo objetivo principal es la comprensión del desarrollo y decadencia de la cultura Nasca en la parte alta de la cuenca del Río Grande de Nasca, así como sus afinidades biológicas y culturales con su antecesora, la cultura Paracas. Se realizaron análisis de ADN antiguo en más de 300 individuos procedentes de varios cementerios prehispánicos del sur del Perú correspondientes a un lapso que se inicia en el Período Formativo y alcanza el Horizonte Medio. Los resultados muestran que las poblaciones nasca son cercanas a las de su cultura precedente. Esta información, combinada con los datos arqueológicos, sugiere que la cultura Nasca se desarrolló, de manera autóctona, en la cuenca del Río Grande. Más aún, se puede observar que los cambios socioeconómicos de este período influyeron en la diversidad genética. Las poblaciones prehispánicas costeñas del sur del Perú difieren, significativamente, de las antiguas poblaciones de la sierra y de las poblaciones peruanas actuales. La diferenciación genética entre las principales áreas culturales de la parte oeste de Sudamérica parece desaparecer en el Horizonte Medio.

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