title: The past and present of an estuarine-resident fish, the "four-eyed fish" Anableps anableps (Cyprinodontiformes, Anablepidae), revealed by mtDNA sequences.
abstract: Historical events, such as changes in sea level during the Pleistocene glacial cycles, had a strong impact on coastal habitats, limiting connectivity and promoting the genetic divergence of various species. In this study, we evaluated the influence of climate oscillations and the possibility of estuary function as a barrier to gene flow among populations of the four-eyed fish, Anableps anableps. This species is fully estuarine-resident, has internal fertilization, is viviparous and does not migrate across long distances. These features make the four-eyed fish an excellent model for the study of evolutionary processes related to genetic differentiation of species and populations in estuaries. The evolutionary history of A. anableps was inferred from phylogeographic and population analyses using sequences of the mitochondrial DNA Control Region of 13 populations distributed in the Amazon and Northeast Coast of Brazil from Calcoene (Amapa) to Parnaiba (Piaui). The 83 retrieved haplotypes show a pattern of four distinct mitochondrial lineages, with up to 3.4% nucleotide divergence among them. The evolutionary reconstruction suggests that these lineages diverged recently in the late Pleistocene/early Holocene after the Atlantic Ocean reaching current levels. Analysis of variability, neutrality and the genetic expansion pattern revealed that the lineages have distinct characteristics, which were shaped by the different geomorphological features of coastal regions combined with sea level oscillations over a very long period of time. Only few neighboring populations show a discreet gene flow. This study may also be helpful for designing new experiments to better understand the geomorphological evolutionary history of the estuaries of the Amazon and the Northeast Coast of Brazil using estuarine-resident species as a model.
authors.affiliation: Laboratório de Filogenômica e Bioinformática, Instituto de Estudos Costeiros, Universidade Federal do Para (UFPA), Campus de Bragança, Brazil.
authors.forename: Luciana Almeida
authors.initials: LA
authors.lastname: Watanabe
authors.affiliation: Laboratório de Filogenômica e Bioinformática, Instituto de Estudos Costeiros, Universidade Federal do Para (UFPA), Campus de Bragança, Brazil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Vallinoto
authors.affiliation: Laboratório de Geologia Costeira, Instituto de Estudos Costeiros, Universidade Federal do Para (UFPA), Campus de Bragança, Brazil.
authors.forename: Nils Asp
authors.initials: NA
authors.lastname: Neto
authors.affiliation: Laboratório de Filogenômica e Bioinformática, Instituto de Estudos Costeiros, Universidade Federal do Para (UFPA), Campus de Bragança, Brazil.
authors.forename: Janice
authors.initials: J
authors.lastname: Muriel-Cunha
authors.affiliation: Center for Marine Tropical Ecology, University of Bremen, Bremen, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Saint-Paul
authors.affiliation: Laboratório de Filogenômica e Bioinformática, Instituto de Estudos Costeiros, Universidade Federal do Para (UFPA), Campus de Bragança, Brazil.
authors.forename: Horacio
authors.initials: H
authors.lastname: Schneider
authors.affiliation: Laboratório de Filogenômica e Bioinformática, Instituto de Estudos Costeiros, Universidade Federal do Para (UFPA), Campus de Bragança, Brazil.
authors.forename: Iracilda
authors.initials: I
authors.lastname: Sampaio
mesh_terms: D000818:Animals; D001938:Brazil; D003532:Cyprinodontiformes / Q000145:classification / Q000235:genetics*; D004272:DNA, Mitochondrial; D019143:Evolution, Molecular; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes; D008969:Molecular Sequence Data; D010802:Phylogeny; D058974:Phylogeography
chemical_list: D004272:DNA, Mitochondrial