Estrutura populacional de Aspidosperma polyneuron Muel. Arg. (Apocynaceae) em fragmento florestal do baixo Rio Tibagi por marcadores AFLP

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

02/03/2010

RESUMO

The XXI century is characterized by intense fragmentation of tropical forests around the word which is responsible for environmental degradation, climate changes and loss of biodiversity. Such process is the focus of many studies that intend, primarily, to identify the effect of devastation in the gene pool of species that occupy degraded areas. The Tibagi River basin, situated in the east-center portion of the ParanA State with an approximate area of 24.711Km2, comprising around 13% of the area of the State. Extending through different climate zones, the vegetation of the Tibagi River basin is highly heterogeneous. However, due to the colonization process that occurred in the last 50 years, the flora of the region has being highly impacted and the native forest cover corresponds, nowadays, to only 3.8% of its original area. Within these fragments many populations of tree species are more or less isolated. Molecular markers techniques have been widely used in studies of anthropogenic impacted areas. In the present study AFLP molecular markers were used to investigate the genetic structure of two native samples of A. polyneuron Muell. Arg. from an accentuated slope area (AS) and a flat area (FA) situated in the Doralice Farm, IbiporA County, ParanA State, Brazil. The distance between the slope and the flat areas was of 200 meters. Seven pairs of selective primers generated 200 AFLP markers of which 99% and 88.5% were polymorphic for the AS and FA areas, respectively. The coefficient of variation for the number of amplified markers was below 1%, revealing a good level of trustworthiness in our results. The genetic diversity (Hs) was 0.3719 for the AS sample and 0.3072 for the FA area, showing a higher genetic diversity for the sample of slope area. The value of Fst was 0.26485 with a genetic distance of 0.1479 between the samples. PCoA clustering analysis revealing the formation of three distinct clusters. The first cluster was formed by individuals from AS samples, the second group contains both individuals from AS and FA samples, and the third cluster contains only individuals from FA area. Bayesian analysis for K number of clusters further supported the results from PCoA, indicating that in 95.3% of the times individuals were assigned to the three clusters. These results can be used as a parameter to evaluate the genetic impact of disturbed habitat for this and other tree species in semideciduous forest fragments and to provide a source of genetic variation for recovering degraded areas.

ASSUNTO(S)

apocináceas genética florestal florestas - conservação degradação ambiental marcadores biológicos apocynaceae forest genetics

ACESSO AO ARTIGO

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