title: Population genetic structure  of the tropical tree species Aegiphila sellowiana (Lamiaceae).
abstract: The  Tibagi River, located in southern Brazil, is associated with a significant  degree of environmental heterogeneity, along its 550 km extension. There is  concern about the integrity of this river's ecosystem, as human interference  has been increasing. Aegiphila sellowiana (Lamiaceae) is an important  pioneer tree species, commonly found near rivers; the fruit is consumed by  avifauna. We studied this species along three ecological gradients, comprising  the upper, middle, and lower regions of the Tibagi River basin. The genetic  structure of nine subpopulations of A. sellowiana distributed along  these gradients was investigated using RAPDs. Moderate levels of gene diversity  (ranging from 0.091 to 0.132) were identified, inferred by a traditional  approach and a Bayesian model-based method. The F-statistic, G(ST) parameters  and molecular variance analysis showed high genetic differentiation among the  three regions (39.5 to 50.26%). Analysis of molecular variance revealed high  levels of genetic variation between populations (50.26%), while lower values of  genetic variation (ranging from 9.56 to 16.35%) were seen between  subpopulations within the upper, middle, and lower regions of the Tibagi River  basin. The validity of these results was confirmed by principal coordinate  analysis. Linear regression analysis showed significant correlations (r =  0.621, P = 0.0001) between the genetic and geographical distances. The  differences observed in genetic variation between regions are probably due to  habitat fragmentation; for conservation purposes, we recommend that at least  one subpopulation from each region of the Tibagi River should be maintained.
authors.affiliation: Departamento de Biologia Geral, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Londrina, PR, Brasil.
authors.forename: C
authors.initials: C
authors.lastname: Medri
authors.forename: E A
authors.initials: EA
authors.lastname: Ruas
authors.forename: C F
authors.initials: CF
authors.lastname: Ruas
authors.forename: P S
authors.initials: PS
authors.lastname: Medri
authors.forename: M E
authors.initials: ME
authors.lastname: Medri
authors.forename: P M
authors.initials: PM
authors.lastname: Ruas
mesh_terms: D001499:Bayes Theorem; D001938:Brazil; D017753:Ecosystem; D005819:Genetic Markers; D014644:Genetic Variation; D019686:Lamiaceae / Q000235:genetics*; D025341:Principal Component Analysis; D019105:Random Amplified Polymorphic DNA Technique; D045483:Rivers; D014197:Trees / Q000235:genetics*
chemical_list: D005819:Genetic Markers