102,302 research outputs found
Mitochondrial and Y-chromosome diversity of the Tharus (Nepal): a reservoir of genetic variation
No full textBackground
Central Asia and the Indian subcontinent represent an area considered as a source and a reservoir for human genetic diversity, with many markers taking root here, most of which are the ancestral state of eastern and western haplogroups, while others are local. Between these two regions, Terai (Nepal) is a pivotal passageway allowing, in different times, multiple population interactions, although because of its highly malarial environment, it was scarcely inhabited until a few decades ago, when malaria was eradicated. One of the oldest and the largest indigenous people of Terai is represented by the malaria resistant Tharus, whose gene pool could still retain traces of ancient complex interactions. Until now, however, investigations on their genetic structure have been scarce mainly identifying East Asian signatures.
Results
High-resolution analyses of mitochondrial-DNA (including 34 complete sequences) and Y-chromosome (67 SNPs and 12 STRs) variations carried out in 173 Tharus (two groups from Central and one from Eastern Terai), and 104 Indians (Hindus from Terai and New Delhi and tribals from Andhra Pradesh) allowed the identification of three principal components: East Asian, West Eurasian and Indian, the last including both local and inter-regional sub-components, at least for the Y chromosome.
Conclusion
Although remarkable quantitative and qualitative differences appear among the various population groups and also between sexes within the same group, many mitochondrial-DNA and Y-chromosome lineages are shared or derived from ancient Indian haplogroups, thus revealing a deep shared ancestry between Tharus and Indians. Interestingly, the local Y-chromosome Indian component observed in the Andhra-Pradesh tribals is present in all Tharu groups, whereas the inter-regional component strongly prevails in the two Hindu samples and other Nepalese populations.
The complete sequencing of mtDNAs from unresolved haplogroups also provided informative markers that greatly improved the mtDNA phylogeny and allowed the identification of ancient relationships between Tharus and Malaysia, the Andaman Islands and Japan as well as between India and North and East Africa. Overall, this study gives a paradigmatic example of the importance of genetic isolates in revealing variants not easily detectable in the general population
Formal Properties of the SCIFF-AF Multiagent Argumentation Framework
No full textArgumentation theories have recently emerged and gained popularity in the agents community, since argumentation represents a natural and intuitive way to model non-monotonic reasoning. In a multi-agent context, argumentation has recently been proposed as a component of dialogue frameworks. However, despite the large interest in argumentation theories in multiagent domains, most proposed frameworks stay at a general though abstract level, and operational counterparts to abstract frameworks are not many. The aim of this work is to present the main formal properties of the SCIFF-AF: an operational argumentation-based multiagent dialogue framework
In search of the genetic footprints of Sumerians: a survey of Y-chromosome and mtDNA variation in the Marsh Arabs of Iraq
No full textBackground
For millennia, the southern part of the Mesopotamia has been a wetland region generated by the Tigris and Euphrates rivers before flowing into the Gulf. This area has been occupied by human communities since ancient times and the present-day inhabitants, the Marsh Arabs, are considered the population with the strongest link to ancient Sumerians. Popular tradition, however, considers the Marsh Arabs as a foreign group, of unknown origin, which arrived in the marshlands when the rearing of water buffalo was introduced to the region.
Results
To shed some light on the paternal and maternal origin of this population, Y chromosome and mitochondrial DNA (mtDNA) variation was surveyed in 143 Marsh Arabs and in a large sample of Iraqi controls. Analyses of the haplogroups and sub-haplogroups observed in the Marsh Arabs revealed a prevalent autochthonous Middle Eastern component for both male and female gene pools, with weak South-West Asian and African contributions, more evident in mtDNA. A higher male than female homogeneity is characteristic of the Marsh Arab gene pool, likely due to a strong male genetic drift determined by socio-cultural factors (patrilocality, polygamy, unequal male and female migration rates).
Conclusions
Evidence of genetic stratification ascribable to the Sumerian development was provided by the Y-chromosome data where the J1-Page08 branch reveals a local expansion, almost contemporary with the Sumerian City State period that characterized Southern Mesopotamia. On the other hand, a more ancient background shared with Northern Mesopotamia is revealed by the less represented Y-chromosome lineage J1-M267*. Overall our results indicate that the introduction of water buffalo breeding and rice farming, most likely from the Indian sub-continent, only marginally affected the gene pool of autochthonous people of the region. Furthermore, a prevalent Middle Eastern ancestry of the modern population of the marshes of southern Iraq implies that if the Marsh Arabs are descendants of the ancient Sumerians, also the Sumerians were most likely autochthonous and not of Indian or South Asian ancestry
Association of the mtDNA m.4171C>A/MT-ND1 mutation with both optic neuropathy and bilateral brainstem lesions
No full textBackground: An increasing number of mitochondrial DNA (mtDNA) mutations, mainly in complex I genes, have
been associated with variably overlapping phenotypes of Leber’s hereditary optic neuropathy (LHON),
mitochondrial encephalomyopathy with stroke-like episodes (MELAS) and Leigh syndrome (LS). We here describe
the first case in which the m.4171C>A/MT-ND1 mutation, previously reported only in association with LHON, leads
also to a Leigh-like phenotype.
Case presentation: A 16-year-old male suffered subacute visual loss and recurrent vomiting and vertigo associated
with bilateral brainstem lesions affecting the vestibular nuclei. His mother and one sister also presented subacute
visual loss compatible with LHON. Sequencing of the entire mtDNA revealed the homoplasmic m.4171C>A/MT-ND1
mutation, previously associated with pure LHON, on a haplogroup H background. Three additional non-synonymous
homoplasmic transitions affecting ND2 (m.4705T>C/MT-ND2 and m.5263C>T/MT-ND2) and ND6 (m.14180T>C/MT-ND6)
subunits, well recognized as polymorphisms in other mtDNA haplogroups but never found on the haplogroup H
background, were also present.
Conclusion: This case widens the phenotypic expression of the rare m.4171C>A/MT-ND1 LHON mutation, which
may also lead to Leigh-like brainstem lesions, and indicates that the co-occurrence of other ND non-synonymous
variants, found outside of their usual mtDNA backgrounds, may have increased the pathogenic potential of the
primary LHON mutation
Author Correction: Uncovering the sources of DNA found on the Turin Shroud
No full textAn amendment to this paper has been published and can be accessed via a link at the top of the paper
First International Workshop, ArgNMR 2007, Tempe, Arizona, US, May 14, 2007, Proceedings
No full textResearch on argumentation and non-monotonic reasoning began in full force in the early eighties. The first attempts showed how argumentation results in a very natural way of conceptualizing commonsense reasoning, appropriately reflecting its defeasible nature. Further work in the knowledge representation and reasoning community has shown that argumentation provides a useful perspective for relating different non-monotonic formalisms. More recently, argumentation has been revealed as a powerful conceptual tool for exploring the theoretical foundations of reasoning and interaction in autonomous agents and multiagent systems.
This volume contains the papers that will be presented at the First International Workshop on Argumentation and Non-Monotonic Reasoning (ArgNMR 2007) on May 14, 2007 in Tempe, Arizona, US. Each submission was reviewed by at least 3 programme committee members.
In covers topics ranging from fundamental theoretical basis to design and implementation of argument-based systems including semantics, proof theory, applications and the comparison of those systems with other types of non-monotonic reasoning
The importance of the head and neck region in regression of advanced MCC: a clinical report.
No full textThis paper presents the case of a 76-year-old woman who experienced a total regression of a Merkel cell carcinoma (MCC). The primary site of the tumor was on her right eyebrow. After this lesion was excised, the patient presented a massive locoregional metastasis on the right parotid gland and the laterocervical lymph nodes. No distant metastases were detected. An incisional biopsy into the right parotid gland confirmed the diagnosis of MCC metastasis. No surgical treatment was prescribed because of the advanced stage of the disease. Spontaneous total regression on the parotid and the neck mass was observed within 3 months. This is the 15th case of spontaneous regression in total and the 14th case with a site of origin in the head and neck region. ©2007Muntaz B. Habal, MD
Reactions of C5H5M+ (M=Fe, Ni) with substituted thiophenes.
No full textThe ion molecule reactions between C5H5M+ (M =Fe, Ni) with some substituted thiophenes have been studied in an ion trap mass
spectrometer. The reactions of halogen substituted thiophenes lead to the formation of a new C–C bond between the cyclopentadiene ring and the thiophene with the loss of a neutral HX. The reaction mechanism has been investigated by means of DFT calculations
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