7 research outputs found
Drivers of population structure of the bottlenose dolphin (Tursiops truncatus) in the Eastern Mediterranean Sea
The drivers of population differentiation in oceanic high dispersal organisms, have been crucial for research in evolutionary biology. Adaptation to different environments is commonly invoked as a driver of differentiation in the oceans, in alternative to geographic isolation. In this study, we investigate the population structure and phylogeography of the bottlenose dolphin (Tursiops truncatus) in the Mediterranean Sea, using microsatellite loci and the entire mtDNA control region. By further comparing the Mediterranean populations with the well described Atlantic populations, we addressed the following hypotheses: (1) bottlenose dolphins show population structure within the environmentally complex Eastern Mediterranean Sea; (2) population structure was gained locally or otherwise results from chance distribution of preexisting genetic structure; (3) strong demographic variations within the Mediterranean basin have affected genetic variation sufficiently to bias detected patterns of population structure. Our results suggest that bottlenose dolphin exhibits population structures that correspond well to the main Mediterranean oceanographic basins. Furthermore, we found evidence for fine scale population division within the Adriatic and the Levantine seas. We further describe for the first time, a distinction between populations inhabiting pelagic and coastal regions within the Mediterranean. Phylogeographic analysis suggests that current genetic structure, results mostly from stochastic distribution of Atlantic genetic variation, during a recent postglacial expansion. Comparison with Atlantic mtDNA haplotypes, further suggest the existence of a metapopulation across North Atlantic/Mediterranean, with pelagic regions acting as source for coastal environments
Neue linguistische Methoden und arbeitstechnische Verfahren in der Erschliessung der Àgyptischen Grammatik
15 pĂĄginas, 1 tabla, 6 figuras.Does diversity beget diversity? Diversity
includes a diversity of concepts because it is linked to
variability in and of life and can be applied to multiple
levels. The connections between multiple levels of
diversity are poorly understood. Here, we investigated
the relationships between genetic, bacterial, and
chemical diversity of the endangered Atlanto-Mediterranean sponge Spongia lamella. These levels of
diversity are intrinsically related to sponge evolution
and could have strong conservation implications. We
used microsatellite markers, denaturing gel gradient
electrophoresis and quantitative polymerase chain
reaction, and high performance liquid chromatography to quantify genetic, bacterial, and chemical
diversity of nine sponge populations. We then used
correlations to test whether these diversity levels
covaried. We found that sponge populations differed
signiïŹcantly in genetic, bacterial, and chemical
diversity. We also found a strong geographic pattern
of increasing genetic, bacterial, and chemical dissimilarity with increasing geographic distance between
populations. However, we failed to detect signiïŹcant
correlations between the three levels of diversity
investigated in our study. Our results suggest that
diversity fails to beget diversity within a single species
and indicates that a diversity of factors regulates a
diversity of diversities, which highlights the complex
nature of the mechanisms behind diversityResearch funded by grants from the Agence Nationale de la
Recherche (ECIMAR), from the Spanish Ministry of Science
and Technology SOLID (CTM2010-17755) and Benthomics
(CTM2010-22218-C02-01) and the BIOCAPITAL project
(MRTN-CT-2004-512301) of the European Union. This is a
contribution of the Consolidated Research Group ââGrupo de
EcologıŽa BentoÂŽnica,ââ SGR2009-655.Peer reviewe
Governing through the border : (post)colonial governmentality in Gibraltar
While the management of the frontier separating Gibraltar from Spain is frequently contested by the inhabitants and the tiny British Overseas Territory and stays at the core of a tense international dispute between the United Kingdom and Spain, this work subverts views of the border as a threat or an obstacle to the normalization of political life in the tiny (post)colonial enclave. Here, Gibraltar is analysed as a micro state whose inhabitantsâ identity and practices of self-government generate from the border â rather than in opposition to it. As such, we show how the tightening of the frontier allows the discursive production of a Gibraltarian national identity as distinct from that of the Spanish neighbours that is central to maintain British control on the enclave.This chapter offers a critical analysis of the functioning of the border dividing Gibraltar from Spain. Whereas the management of this frontier is frequently contested by the inhabitants and the government of the Rock, and often causes tense disputes between the UK and Spain, this chapter challenges views of the border as a threat or an obstacle to the normalisation of political life in the tiny enclave. Here, Gibraltar is analysed instead as a microstate whose inhabitantsâ identity and practices of self-government generate from the borderârather than in opposition to it. By concentrating on the period when the frontier between Gibraltar and the neighbouring Spanish town of La LĂnea de la ConcepciĂłn was closed by Francoâs regime, we show how the tightening of the frontier allowed the discursive production of a Gibraltarian national identity as distinct from that of the Spanish neighboursâas well as, partly, from that of the British colonial mastersâthat played a central role for the partial decolonisation of Gibraltar. Here, we discuss the border between Gibraltar and the Spanish town of La LĂnea as a security apparatus that stays at the foundations of Gibraltariansâ ambiguous articulation of independent self-government and British control
Adaptation Without Boundaries: Population Genomics in Marine Systems
From the surface, the worldâs oceans appear vast and boundless. Ocean currents, which can transport marine organisms thousands of kilometers, coupled with species that spend some or all of their life in the pelagic zone, the open sea, highlight the potential for well-mixed, panmictic marine populations. Yet these ocean habitats do harbor boundaries. In this largely three-dimensional marine environment, gradients form boundaries. These gradients include temperature, salinity, and oxygen gradients. Ocean currents also form boundaries between neighboring water masses even as they can break through barriers by transporting organisms huge distances. With the advent of next-generation sequencing approaches, which allow us to easily generate a large number of genomic markers, we are in an unprecedented position to study the effects of these potential oceanic boundaries and can ask how often and when do locally adapted marine populations evolve. This knowledge will inform our understanding of how marine organisms respond to climate change and affect how we protect marine diversity. In this chapter I first discuss the major boundaries present in the marine environment and the implications they have for marine organisms. Next, I discuss the how genomic approaches are impacting our understanding of genetic connectivity, ocean fisheries, and local adaptation, including the potential for epigenetic adaptation. I conclude with considerations for marine conservation and management and future prospects