title: A preliminary study of genetic variation in populations of Monstera adansonii var. klotzschiana (Araceae) from North-East Brazil, estimated with AFLP molecular markers.
abstract: OBJECTIVE
  This study sought genetic evidence of long-term isolation in populations of Monstera adansonii var. klotzschiana (Araceae), a herbaceous, probably outbreeding, humid forest hemi-epiphyte, in the brejo forests of Ceará (north-east Brazil), and clarification of their relationships with populations in Amazonia and the Atlantic forest of Brazil.
  
  
  METHODS
  Within-population genetic diversity and between-population dissimilarity were estimated using AFLP molecular markers in 75 individuals from eight populations located in Ceará, the Brazilian Atlantic Forest and Amazonia.
  
  
  RESULTS
  The populations showed a clinal pattern of weak genetic differentiation over a large geographical region (F(ST) = 0.1896). A strong correlation between genetic and geographical distance (Mantel test: r = 0.6903, P = 0.002) suggests a historical pattern of isolation by distance. Genetic structure analysis revealed at least two distinct gene pools in the data. The two isolated Ceará populations are significantly different from each other (pairwise Phi(PT) = 0.137, P = 0.003) and as diverse (Nei's gene diversity, average H(e) = 0.1832, 0.1706) as those in the Atlantic and Amazon forest regions. The population in southern Brazil is less diverse (Nei's gene diversity, average H(e) = 0.127) than the rest. The Ceará populations are related to those of the Atlantic forest rather than those from Amazonia (AMOVA, among-groups variation = 11.95 %, P = 0.037).
  
  
  CONCLUSIONS
  The gene pools detected within an overall pattern of clinal variation suggest distinct episodes of gene flow, possibly correlated with past humid forest expansions. The Ceará populations show no evidence of erosion of genetic diversity, although this was expected because of their isolation. Their genetic differentiation and relatively high diversity reinforce the importance of conserving the endangered brejo forests.
authors.affiliation: Programa de Pós-Graduação em Botânica, Universidade Estadual de Feira de Santana (UEFS), Departamento de Ciências Biológicas, Avenida Universitária s/n, 44031-460, Feira de Santana, Bahia, Brazil.
authors.forename: I M
authors.initials: IM
authors.lastname: Andrade
authors.forename: S J
authors.initials: SJ
authors.lastname: Mayo
authors.forename: C
authors.initials: C
authors.lastname: van den Berg
authors.forename: M F
authors.initials: MF
authors.lastname: Fay
authors.forename: M
authors.initials: M
authors.lastname: Chester
authors.forename: C
authors.initials: C
authors.lastname: Lexer
authors.forename: D
authors.initials: D
authors.lastname: Kirkup
mesh_terms: D054458:Amplified Fragment Length Polymorphism Analysis; D029064:Araceae / Q000235:genetics*; D001938:Brazil; D051456:Gene Flow / Q000235:genetics; D005819:Genetic Markers / Q000235:genetics; D014644:Genetic Variation; D005828:Genetics, Population; D011110:Polymorphism, Genetic