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Browsing by Author "Garcia, M."

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  • Applying genomic approaches to delineate conservation strategies using the freshwater mussel Margaritifera margaritifera in the Iberian Peninsula as a model
    Publication . Perea, S.; Mendes, Sofia L.; Sousa-Santos, C.; Ondina, P.; Amaro, R.; Castro, J.; San-Miguel, E.; Lima, C. S.; Garcia, M.; Velasquez, V.; Garcia-Roves, P.; Fernández, D.; Araujo, R.; Sousa, Vitor C; Reis, J.
    Effective conservation actions to counteract the current decline of populations and species require a deep knowledge on their genetic structure. We used Single Nucleotide Polymorphisms (SNPs) to infer the population structure of the highly threatened freshwater pearl mussel Margaritifera margaritifera in the Iberian Peninsula. A total of 130 individuals were collected from 26 locations belonging to 16 basins. We obtained 31,692 SNPs through Genotyping by Sequencing (GBS) and used this dataset to infer population structure. Genetic diversity given as observed heterozygosity was low. Pairwise FST comparisons revealed low levels of genetic differentiation among geographically close populations. Up to 3 major genetic lineages were determined: Atlantic, Cantabrian and Douro. This structure suggests a close co-evolutionary process with brown trout (Salmo trutta), the primordial fish host of this mussel in the studied area. Some sub-basins showed some genetic structuring, whereas in others no intrapopulation differentiation was found. Our results confirm that genetic conservation units do not match individual basins, and that knowledge about the genetic structure is necessary before planning recovery plans that may involve relocation or restocking. The same reasoning should be applied to strictly freshwater species that are sessile or have restricted dispersal abilities and are currently imperiled worldwide.
    2022-10Journal article Unknown Show more
  • Increased frequency of circulating CCR5+ CD4+ T cells in human immunodeficiency virus type 2 infection
    Publication . Soares, R.; Foxall, R.; Albuquerque, A.; Cortesão, C.; Garcia, M.; Victorino, R. M.; Sousa, A. E.
    CCR5 expression determines susceptibility to infection, cell tropism, and the rate of human immunodeficiency virus type 1 (HIV-1) disease progression. CCR5 is also considered the major HIV-2 coreceptor in vivo, in spite of broad coreceptor use in vitro. Here we report a significantly increased proportion of memory-effector CD4 T cells expressing CCR5 in HIV-2-infected patients correlating with CD4 depletion. Moreover, HIV-2 proviral DNA was essentially restricted to memory-effector CD4, suggesting that this is the main target for HIV-2. Similar levels of proviral DNA were found in the two infection categories. Thus, the reduced viremia and slow rate of CD4 decline that characterize HIV-2 infection seem to be unrelated to coreceptor availability.
    2006Journal article Unknown Show more