Navegando por Palavras-chave "microsatellites"

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    Phylogeography and genetic differentiation along the distributional range of the orchid Epidendrum fulgens: a Neotropical coastal species not restricted to glacial refugia
    (Wiley-Blackwell, 2011-10-01) Pinheiro, Fabio [UNIFESP]; Barros, Fabio de; Palma-Silva, Clarisse; Fay, Michael F.; Lexer, Christian; Cozzolino, Salvatore; Inst Bot; Universidade Federal de São Paulo (UNIFESP); Royal Bot Gardens; Univ Fribourg; Univ Naples Federico II
    Aim Phylogeographical studies in the Brazilian Atlantic Forest (BAF) have mostly included species associated with forest habitats, whereas taxa associated with grassland and sand-dune plant communities have so far been largely overlooked. This study examines the phylogeography of the orchid Epidendrum fulgens, which occurs on coastal sand dunes and granitic outcrops, in order to identify major genetic divergences or disjunctions across the range of the species and to investigate the genetic signatures of past range contractions and expansions.Location Southern and south-eastern seashore vegetation along the BAF biome, and granitic and arenitic outcrops that occur in the subtropical grassland plant communities located south of the BAF.Methods Nine nuclear and four plastid microsatellite loci were used to genotype 424 individuals from 16 populations across the distributional range of E. fulgens. for both sets of markers, we estimated genetic diversity and population differentiation, testing for a north-south gradient of genetic diversity. the plastid haplotype network and a Bayesian assignment analysis of nuclear markers were used to infer population structure. Past demographic changes were investigated using a coalescence approach.Results A deep disjunction was found between northern populations within the BAF and southern populations outside the BAF that occur on granitic and arenitic outcrops. Recent demographic reductions were detected in northern populations on coastal sands. Such demographic changes were not expected for those populations, as previous studies with forest species had found evidence of population expansion in the same areas. Higher genetic diversity was found in southern populations on granite, in contrast to patterns observed in previous studies of forest species.Main conclusions the results are consistent with the long-term persistence of E. fulgens. Bottlenecks were detected in populations from areas where population expansion events have been detected in other plant (and animal) species, suggesting that forest expansion after the Last Glacial Maximum played a role in the population fragmentation and decrease in genetic diversity in E. fulgens. A substantial genetic division in E. fulgens corresponds to the 'Portal de Torres', a region that demarcates the northern limits of subtropical grassland plant communities and the southern limits of the BAF.
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    Recurrent connections between Amazon and Atlantic forests shaped diversity in Caatinga four-eyed frogs
    (Wiley-Blackwell, 2016) Thome, Maria Tereza C.; Sequeira, Fernando; Brusquetti, Francisco; Carstens, Bryan; Haddad, Celio F. B.; Rodrigues, Miguel Trefaut; Alexandrino, Joao [UNIFESP]
    Aim The Caatinga is a widespread but poorly known biome in South America. Its historical stability is controversial and different types of evidence provide support to contrasting hypotheses. We investigate how past biome dynamics may have caused diversification in the endemic four-eyed frog genus Pleurodema. Location Caatinga biome. Methods We sampled 353 individuals of Pleurodema alium and Pleurodema diplolister from 60 localities and genotyped them at 12 (P. alium) or 20 (P. diplolister) microsatellite loci. We sequenced a mitochondrial fragment for a subset (199) of the samples. After exploratory analyses to infer genetic structure between and within species, we designed seven biogeographical scenarios based on the literature on species distributions, palaeomodels and geological palaeoindicators. We tested these hypotheses by calculating the posterior probability of models using multilocus approximate Bayesian computation (ABC). Results Both markers recovered well-defined interspecific limits with restricted introgression, but population structure within P. diplolister is subtle and affected by isolation by distance. Model selection using ABC supported two scenarios of diversification that included recent demographic growth. Genetic breaks at intra-and interspecific levels were geographically coincident, and correlated with past forest invasions reported in the literature. Main conclusions Our data support the idea that past expansions of the Amazon and Atlantic forests over the current Caatinga distribution shaped the genetic structure in endemic four-eyed frogs at more than one level by promoting intermittent vicariance. Additional support comes from the distribution patterns of forest and Caatinga taxa. Variation among groups suggests differential organismal responses to past habitat shifts, probably mediated by specific natural-history traits. This paper provides the first direct evidence that taxa endemic to the Caatinga were affected by past forest interactions.
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    Transposable elements and two other molecular markers as typing tools for the genus Paracoccidioides
    (Oxford Univ Press, 2015-02-01) Alves, Fernanda Lourenco; Ribeiro, Mariceli Araujo; Hahn, Rosane Christine; Teixeira, Marcus de Melo; Camargo, Zoilo Pires de [UNIFESP]; Cisalpino, Patricia Silva; Marini, Marjorie Mendes [UNIFESP]; Universidade Federal de Minas Gerais (UFMG); Univ Fed Espirito Santo; Univ Fed Mato Grosso; Universidade de Brasília (UnB); Universidade Federal de São Paulo (UNIFESP)
    Studies comparing Paracoccidioides brasiliensis and Paracoccidioides lutzii have shown that these fungi have significant genomic differences that may have implications in the clinical manifestation, diagnosis, and treatment of paracoccidioidomycosis caused by them. Thus, molecular typing methods are required that can distinguish between various species of Paracoccidioides. the aim of this study was to explore the potential use as molecular markers of the transposable elements Trem A-H recently identified and characterized in the genus Paracoccidioides as a means of differentiating the species. We take advantage of the abundance and distribution of these transposons in the Paracoccidioides genomes to develop a simple and highly reproducible polymerase chain reaction (PCR)-based technique. Furthermore we compare the performance of this test with two other molecular markers already in use to identify these fungi.