|Publication Type:||Journal Article|
|Year of Publication:||2007|
|Authors:||Andrade, IM, Mayo, SJ, van den Berg, C, Fay, MF, Chester, M, Lexer, C, Kirkup, D|
|Journal:||Annals of Botany|
† Background and Aims 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 Ceara´ (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 Ceara´, the Brazilian Atlantic Forest and Amazonia. † Key Results The populations showed a clinal pattern of weak genetic differentiation over a large geographical region (FST ¼ 0.1896). A strong correlation between genetic and geographical distance (Mantel test: r ¼ 0.6903, P ¼ 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 Ceara´ populations are significantly different from each other ( pairwise FPT ¼ 0.137, P ¼ 0.003) and as diverse (Nei’s gene diversity, average He ¼ 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 He ¼ 0.127) than the rest. The Ceara´ populations are related to those of the Atlantic forest rather than those from Amazonia (AMOVA, among-groups variation ¼ 11.95 %, P ¼ 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 Ceara´ 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..
A Preliminary Study of Genetic Variation in Populations of Monstera adansonii var. klotzschiana (Araceae) from North-East Brazil, Estimated with AFLP Molecular Markers