title: Could refuge theory and rivers acting as barriers explain the genetic variability distribution in the Atlantic Forest?
abstract: The Atlantic Forest is one of the most species-rich ecoregions in the world. The historical origins of this richness and the evolutionary processes that produced diversification and promoted speciation in this ecosystem remain poorly understood. In this context, focusing on Passiflora contracta, an endemic species from the Atlantic Forest distributed exclusively at sea level along forest edges, this study aimed to characterize the patterns of genetic variability and explore two hypotheses that attempt to explain the possible causes of the genetic diversity in this region: the refuge and riverine barrier theories. We employed Bayesian methods combined with niche modeling to identify genetically homogeneous groups, to determine the diversification age, and identify long-term climate stability areas to species survival. The analyses were performed using molecular markers from nuclear and plastid genomes, with samples collected throughout the entire geographic distribution of the species, and comparisons with congeners species. The results indicated that populations were genetically structured and provided evidence of demographic stability. The molecular markers indicated the existence of a clear structure and the presence of five homogeneous groups. Interestingly, the separation of the groups coincides with the geographical locations of local rivers, corroborating the hypothesis of rivers acting as barriers to gene flow in this species. The highest levels of genetic diversity and the areas identified as having long-term climate stability were found in the same region reported for other species as a possible refuge area during the climatic changes of the Quaternary.
authors.affiliation: Laboratory of Molecular Evolution, Department of Genetics, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501-970, Brazil.
authors.forename: Ana Luiza R
authors.initials: ALR
authors.lastname: Cazé
authors.affiliation: Laboratory of Molecular Evolution, Department of Genetics, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501-970, Brazil.
authors.forename: Geraldo
authors.initials: G
authors.lastname: Mäder
authors.affiliation: Department of Biological Sciences, Universidade Estadual de Feira de Santana, Av. Universitária Km 3, 44031-460 Feira de Santana, BA, Brazil.
authors.forename: Teonildes S
authors.initials: TS
authors.lastname: Nunes
authors.affiliation: Department of Biological Sciences, Universidade Estadual de Feira de Santana, Av. Universitária Km 3, 44031-460 Feira de Santana, BA, Brazil.
authors.forename: Luciano P
authors.initials: LP
authors.lastname: Queiroz
authors.affiliation: Department of Ecology, Universidade Federal de Goiás, Campus II, 74001-970 Goiânia, GO, Brazil; Laboratory of Conservation Biogeography and Animal Behavior, Center of Agricultural, Environmental and Biological Sciences, Universidade Federal do Recôncavo da Bahia, Rua Rui Barbosa 710, Centro, Cruz das Almas, BA, Brazil.
authors.forename: Guilherme
authors.initials: G
authors.lastname: de Oliveira
authors.affiliation: Department of Ecology, Universidade Federal de Goiás, Campus II, 74001-970 Goiânia, GO, Brazil.
authors.forename: José Alexandre F
authors.initials: JAF
authors.lastname: Diniz-Filho
authors.affiliation: Laboratory of Genomic and Molecular Biology, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS 90610-001, Brazil.
authors.forename: Sandro L
authors.initials: SL
authors.lastname: Bonatto
authors.affiliation: Laboratory of Molecular Evolution, Department of Genetics, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501-970, Brazil. Electronic address: loreta.freitas@ufrgs.br.
authors.forename: Loreta B
authors.initials: LB
authors.lastname: Freitas
mesh_terms: D005075:Biological Evolution; D018744:DNA, Plant / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D017753:Ecosystem; D065928:Forests; D051456:Gene Flow; D014644:Genetic Variation; D031683:Passifloraceae / Q000145:classification* / Q000235:genetics; D010802:Phylogeny; D045483:Rivers; D017422:Sequence Analysis, DNA
chemical_list: D018744:DNA, Plant
keywords: Bayesian inference; Ecological niche modeling; Passiflora contracta; Phylogenetic positioning; Pleistocene; Quaternary