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Abstract: The Global Positioning System (GPS) has been increasingly used during the past decade to monitor the movements of free-ranging animals. This technology allows to automatically relocate fitted animals, which often results into a high-frequency sampling of their trajectory during the study period. However, depending on the objective of trajectory analysis, this study may quickly become difficult, due to the lack of well designed computer programs. For example, the trajectory may be built by several “parts” corresponding to different behaviours of the animal, and the aim of the analysis could be to identify the different parts, and thereby the different activities, based on the properties of the trajectory. This complex task needs to be performed into a flexible computing environment, to facilitate exploratory analysis of its properties. In this paper, we present a new class of object of the R software, the class “ltraj” included in the package adehabitat, allowing the analysis of animals'' trajectories. We developed this class of data after an extensive review of the literature on the analysis of animal movements. This class of data facilitates the computation of descriptive parameters of the trajectory (such as the relative angles between successive moves, distance between successive relocations, etc.), graphical exploration of these parameters, as well a numerous tests and analyses developed in the literature (first passage time, trajectory partitioning, etc.). Finally, this package also contains numerous examples of animal trajectories, and a working example illustrating the use of the package. [Copyright &y& Elsevier]

Abstract: We studied the possible effects of the expansion of ancient Mediterranean civilizations during the five centuries before and after Christ on the European distribution of the mutant allele for the chemokine receptor gene CCR5 which has a 32-bp deletion (CCR5-Δ32). There is a strong evidence for the unitary origin of the CCR5-Δ32 mutation, this it is found principally in Europe and Western Asia, with generally a north–south downhill cline frequency. Homozygous carriers of this mutation show a resistance to HIV-1 infection and a slower progression towards AIDS. However, HIV has clearly emerged too recently to have been the selective force on CCR5. Our analyses showed strong negative correlations in Europe between the allele frequency and two historical parameters, i.e. the first colonization dates by the great ancient Mediterranean civilizations, and the distances from the Northern frontiers of the Roman Empire in its greatest expansion. Moreover, other studies have shown that the deletion frequencies in both German Bronze Age and Swedish Neolithic populations were similar to those found in the corresponding modern populations, and this deletion has been found in ancient DNA of around 7000 years ago, suggesting that in the past, the deletion frequency could have been relatively high in European populations. In addition, in West Nile virus pathogenesis, CCR5 plays an antimicrobial role showing that host genetic factors are highly pathogen-specific. Our results added to all these previous data suggest that the actual European allele frequency distribution might not be due to genes spreading, but to a negative selection resulting in the spread of pathogens principally during Roman expansion. Indeed, as gene flows from colonizers to European native populations were extremely low, the mutational changes might be associated with vulnerability to imported infections. To date, the nature of the parasites remains unknown; however, zoonoses could be incriminated. [Copyright &y& Elsevier]