title: Cytogenetic variation of repetitive DNA elements in Hoplias malabaricus (Characiformes - Erythrinidae) from white, black and clear water rivers of the Amazon basin.
abstract: Hoplias malabaricus is a common fish species occurring in white, black and clear water rivers of the Amazon basin. Its large distribution across distinct aquatic environments can pose stressful conditions for dispersal and creates possibilities for the emergence of local adaptive profiles. We investigated the chromosomal localization of repetitive DNA markers (constitutive heterochromatin, rDNA and the transposable element REX-3) in populations from the Amazonas river (white water), the Negro river (black water) and the Tapajós river (clear water), in order to address the variation/association of cytogenomic features and environmental conditions. We found a conserved karyotypic macrostructure with a diploid number of 40 chromosomes (20 metacentrics + 20 submetacentrics) in all the samples. Heteromorphism in pair 14 was detected as evidence for the initial differentiation of an XX/XY system. Minor differences detected in the amount of repetitive DNA markers are interpreted as possible signatures of local adaptations to distinct aquatic environments.
authors.affiliation: Laboratório de Genética & Biodiversidade, Instituto de Ciências da Educação, Universidade Federal do Oeste do Pará, Santarém, PA, Brazil.
authors.forename: Fabíola Araújo Dos
authors.initials: FA
authors.lastname: Santos
authors.affiliation: Laboratório de Genética & Biodiversidade, Instituto de Ciências da Educação, Universidade Federal do Oeste do Pará, Santarém, PA, Brazil.
authors.forename: Diego Ferreira
authors.initials: DF
authors.lastname: Marques
authors.affiliation: Laboratório de Citogenética Animal, Instituto de Pesquisas da Amazônia, Manaus, AM, Brazil.
authors.forename: Maria Leandra
authors.initials: ML
authors.lastname: Terencio
authors.affiliation: Laboratório de Citogenética Animal, Instituto de Pesquisas da Amazônia, Manaus, AM, Brazil.
authors.forename: Eliana
authors.initials: E
authors.lastname: Feldberg
authors.affiliation: Laboratório de Genética & Biodiversidade, Instituto de Ciências da Educação, Universidade Federal do Oeste do Pará, Santarém, PA, Brazil.
authors.forename: Luís Reginaldo R
authors.initials: LR
authors.lastname: Rodrigues