Complete mitochondrial DNA sequences provide new insights into the Polynesian motif and the peopling of Madagascar

More than a decade of mitochondrial DNA (mtDNA) studies have given the 'Polynesian motif' renowned status as a marker for tracing the late-Holocene expansion of Austronesian speaking populations. Despite considerable research on the Polynesian motif in Oceania, there has been little equivalent work on the western edge of its expansion - leaving major issues unresolved regarding the motif's evolutionary history. This has also led to considerable uncertainty regarding the settlement of Madagascar. In this study, we assess mtDNA variation in 266 individuals from three Malagasy ethnic groups: the Mikea, Vezo, and Merina. Complete mtDNA genome sequencing reveals a new variant of the Polynesian motif in Madagascar; two coding region mutations define a Malagasy-specific sub-branch. This newly defined 'Malagasy motif' occurs at high frequency in all three ethnic groups (13-50%), and its phylogenetic position, geographic distribution, and estimated age all support a recent origin, but without conclusively identifying a specific source region. Nevertheless, the haplotype's limited diversity, similar to those of other mtDNA haplogroups found in our Malagasy groups, best supports a small number of initial settlers arriving to Madagascar through the same migratory process. Finally, the discovery of this lineage provides a set of new polymorphic positions to help localize the Austronesian ancestors of the Malagasy, as well as uncover the origin and evolution of the Polynesian motif itself

Multiple ethnic origins of mitochondrial DNA lineages for the population of Mauritius

This article reports on the first genetic assessment of the contemporary Mauritian population. Small island nodes such as Mauritius played a critical role in historic globalization processes and revealing high-resolution details of labour sourcing is crucial in order to better understand early-modern diaspora events. Mauritius is a particularly interesting case given detailed historic accounts attesting to European (Dutch, French and British), African and Asian points of origin. Ninety-seven samples were analysed for mitochondrial DNA to begin unravelling the complex dynamics of the island’s modern population. In corroboration with general demographic information, the majority of maternal lineages were derived from South Asia (58.76%), with Malagasy (16.60%), East/Southeast Asian (11.34%) and Sub-Saharan African (10.21%) also making significant contributions. This study pinpoints specific regional origins for the South Asian genetic contribution, showing a greater influence on the contemporary population from northern and southeast India. Moreover, the analysis of lineages related to the slave trade demonstrated that Madagascar and East Asia were the main centres of origin, with less influence from West Africa

Vierecksgittergenerierung und Symmetrische Pflasterung von Geschlossenen Oberflächen

This thesis concerns two fundamental concepts in surface topology. The first part proposes a solution of the problem of generating an all quadrilateral patch layout on a given surface. We approach the problem from a combinatorial graph optimization point of view. Mainly, finding a nice quad layout of a given surface is equivalent to solving a minimum weight perfect matching problem with additional quad guarantee constraints. The results are of high quality in terms of coarseness and alignment to important features of the geometry which can be used for wide range of applications such as hierarchical subdivision or high order surface fitting. The second part suggests an algorithm to symmetrically generate high genus surfaces suitable for space models of regular maps. It is based on a novel identification in hyperbolic space to derive directly the tubular neighborhood of the edge of a tiling directly the the hyperbolic representation followed by a spring relaxation procedure with intersection-free guarantee. We succeed to produce new embeddings of regular maps ranging from genus 5 to 85.Diese Dissertation beschäftigt sich mit zwei grundsätzlichen Konzepten in der Oberflächentopologie. Der erste Teil behandelt das Problem, eine gegebene Oberfläche in Vierecksgitter zu pflastern. Ist eine regelmässige Pflasterung gegeben, werden im zweiten Teil Methoden vorgeschlagen, um eine symmetrische geschlossene Oberfläche zu bauen und diese symmetrisch einzubetten. Oberflächepflasterung hat eine breite Reihe von Anwendung in der Computergrafik und Geometrieverarbeitung. Für eine gegebene Oberfläche schlagen wir einen flexiblen Algorithmus vor, welcher autmoatisch Vierecksgitter von hoher Qualität auf dieser Oberfläche erzeugt. Strukturierte Darstellung einer Oberfläche durch Vierecksgitter hat praktische Anwendungen in unterschiedlichen Bereichen, wie Unterteilungsflächen, Approximation von Oberflächen, Kompression und Hierarchien in der finiten Element Methode. Unser Ansatz besteht darin, einen Singularitäten-Graph eines Rahmenfeldes zu konstruieren. Dieses Feld dekodiert die lokalen Strukturen der Geometrie. Das Problem, ein Vierecksgitter auf der Oberfläche zu erzeugen ist damit äquivalent zur Konstruktion eines minimalen gewichteten Matchings mit disjunkten Nebenbedingungen. Das resultierende Vierecksgitter ist von hoher Qualität in dem Sinne, als das es trotz grober Auflösung den lokalen Strukturen der Geometrie folgt. Anwendungen unserer Methode auf Dreiecks- und Vierecksgitter zeigen, dass die Ergebnisse sich mit denen anderer aktueller Methoden messen können. Für eine gegebene reguläre Pflasterung, präziser eine reguläre Karte, führen wir die entsprechende reguläre Oberfläche ein. Diese ist die passendste Oberfläche von hohem Genus, welche die gegebene Pflasterung realisiert. Das Visualisieren regulärer Karten ist ein schwieriges Problem. Alle regulären Karten, bzw. symmetrischen Pflasterungen einer Oberfläche von Genus bis 302 sind algebraisch bereits bekannt. Sie liegen in Form von Symmetriegruppen vor, welche auf den entsprechenden universellen Abdeckungsräumen agieren. Jedoch ist wenig über die geometrischen Realisierungen bekannt, d.h. über das Finden hoch-symmetrischer Einbettungen abgeschlossener Oberflächen und die passenden hoch-symmetrischen Pflasterungen. In dieser Arbeit führen wir einen Algorithmus ein, welcher automatisch räumliche Modelle für einige dieser regulären Karten erstellt und dabei schöne Oberflächen mit sehr hoher Symmetrie erzeugt

Le projet RESHAPE : connecter les approches évolutives et historiques en santé humaine.

International audienc

Data from: Hodge decomposition of wall shear stress vector fields characterizing biological flows

A discrete boundary-sensitive Hodge decomposition is proposed as a central tool for the analysis of wall shear stress (WSS) vector fields in aortic blood flows. The method is based on novel results for the smooth and discrete Hodge-Morrey-Friedrichs decomposition on manifolds with boundary and subdivides the WSS vector field into five components: gradient (curl-free), co-gradient (divergence-free), and three harmonic fields induced from the boundary, which are called the center, Neumann and Dirichlet fields. First, an analysis of WSS in several simulated simplified phantom geometries (duct and idealized aorta) was performed in order to understand the impact of the five components. It was shown that the decomposition is able to distinguish harmonic blood flow arising from the inlet from harmonic circulations induced by the interior topology of the geometry. Finally, a comparative analysis of 11 patients with coarctation of the aorta (CoA) before and after treatment as well as 10 controls patient was done. The study shows a significant difference between the CoA patients and the healthy controls before and after the treatment. This means a global difference between aortic shapes of diseased and healthy subjects, thus leading to a new type of WSS-based analysis and classification of pathological and physiological blood flow

Genetic neuro-anthropology: Add fun phenotyping to your next field trip!

International audienc