Filogeografia de populações naturais do buriti (Mauritia flexuosa L. f., Arecaceae) do Brasil Central
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2012-04-23
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Universidade Federal de Goiás
Resumo
Mauritia flexuosa, popularly known as buriti, is a large palm that occurs especially in
association with wetlands (veredas) in South America. It is distinguished because of its
economic importance for local populations from Central Brazil, and as source of food,
breeding site and haven for the terrestrial and aquatic fauna. The effect of historical
demographic events and climatic fluctuations in the current distribution of buriti can
provide clues about the responses of this species to anthropic pressures and to future
climatic changes. For this purpose we studied the phylogeography of M. flexuosa. The
results were based on the differences of sequences from the following chloroplast
intergenic regions: psbA-trnH, trnC-ycf6 and trnS-trnG. We sampled 170 individuals
from 14 localities throughout Central Brazil, including populations in the Amazon,
Araguaia/Tocantins, Paraná and São Francisco Basins. Since the distribution of M.
flexuosa is restricted to wetlands, which are surrounded by large areas of dry lands that
may act as barriers to gene flow, we hypothesized that populations are highly
differentiated and that River Basins act as phylogeographic breaks. The combined data
from the three sequence regions generated a fragment of 1205bp, with 11 haplotypes.
Nucleotide diversity was low (π = 0.005314 +/- 0.002800) and haplotipic diversity was
high (h =0,791) for the combined data. The population parameter θ, and nucleotide and
haplotype diversity per population, shows a pattern where populations from different
geographic regions have a relative genetic uniformity, separated by steep losses on the
diversity; what characterizes colonization by sectors. Differentiation among populations
was significant (P< 0.001), but no sign of recent bottleneck on population size followed
by expansion was found (D Tajima=-1.955 p = 0.00210; Mismatch Distribution=0.034
p=0.7467 and growth parameter g=402. 402, 95% = -334.961 ICredi, ICreds 95% =
999.91). We could group populations by location in the phylogenetic analysis (Network
software), but they do not support the initial hypothesis that the major basins act as
important phylogeographic breaks for the distribution of maternal lineages of M.
flexuosa. The studied populations showed ancient time of coalescence. This research
provided more details on the dynamics and genetic structure of the remnant of buriti
populations, helping to elucidate the evolutionary history of this neotropical palm.
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LIMA, N. E. Filogeografia de populações naturais do buriti (Mauritia flexuosa L. f., Arecaceae) do Brasil Central. 2012. 76 f. Dissertação (Mestrado em Genética e Melhoramento de Plantas)–Universidade Federal de Goiás, Goiânia, 2012.