Abstract
The reconstruction of the complex evolutionary history of species is not a simple task as taxonomically problematic groups are often a result of recent speciation events or rapid speciation. Although orchids belonging to the 'Cattleya coccinea' complex have clear diagnostic morphological characters that allow their identification, the delimitation of its seven currently recognized species is problematic. Results of a preliminary study based on ISSR markers and plastid DNA sequences corroborate previous observations on unclear patterns of morphological variation among taxa currently recognized. Within this view, the objective of this study is to understand patterns of diversity between and within populations of the 'Cattleya coccinea' complex from a wider geographic and genetic sampling than the previous study, in order to identify distinct evolutionary lineages and review current delimitation of species for the entire 'Cattleya coccinea' complex. Specifically, this study aims to: (1) measure levels of genetic differentiation within and among populations of species currently belonging to the 'Cattleya coccinea' complex considering the full range of morphological and geographical variation, microsatellite markers and plastid sequences, (2) infer important historical demographic processes, and ecological and evolutionary mechanisms generating the structure patterns observed, and (3) discuss potential evolutionary and conservationist implications of the results for the orchids from the Brazilian Atlantic Forest. With this purpose on mind we intend to develop phylogeographic and population genetic studies based on plastidial DNA sequences and microsatellite markers. Collections will be held in 11 locations in the states of Rio Grande do Sul, Santa Catarina, São Paulo, Rio de Janeiro, Minas Gerais and Espirito Santo, covering all the geographical and morphological distribution observed for the 'Cattleya coccinea' complex. For the plastid sequences analysis, two non-coding sequences already identified as polymorphic will be used, while other primers will be tested to check for the occurrence of additional polymorphic regions. For the microsatellite analysis eight primers already identified as polymorphic will be used and ten extra primers will be tested. With this data, phylogenetic analysis, diversity and population genetic structure analysis will be made, and finally phylogeographic analysis will be held in order to meet the objectives proposed in the study. (AU)
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