Análise populacional de Cichlasoma paranaense (Osteichthyes, Perciformes, Cichlidae) da região do Triângulo Mineiro, Minas Gerais, com base em marcadores citogenéticos e DNA mitocondrial

Abstract

In Brazil, several hydropower plants were bilt over time in Triângulo Mineiro and Alto Paranaiba mesoregion, isolating parts of the rivers. With the construction of reservoirs fish have suffered major impacts, changing the life cycle of those species that are related to hydrological cycles, changing the connectivity between the river and breeding areas. The species Cichlasoma paranaense (family Cichlidae), was chosen because it occurs in different regions of Triângulo Mineiro, and cytogenetic markers used were Ag-NORs, DAPI, Chromomycin and C banding and a molecular was the partial sequencing of the mitochondrial COI. Therefore, the objective was to assess whether the implementation time of the dams on the Rivers Araguari, Tijuco, Paranaiba and Grande was enough to affect the genetic variability of the populations of this species. The basin of the Paranaiba River has a total of sixteen hydroelectric plants installed along its main watercourses. Cytogenetic data on the number and chromosome morphology (2n) of the population confirm the karyotype conservatism of Neotropical cichlids, featuring mostly chromosomes with 2n = 48 subtelo-acrocentrics simple Ag-NORs. Variations in karyotype formula (KF) and markings C banding, and variations in the haplotype network were observed and may be a consequence of population isolation imposed by dam construction over the years in these rivers. The genetic similarity between populations of Rio Grande and Paranaiba, geographically distant, lead us to suggest that other regions of the mtDNA and nuclear DNA must be sequenced and new markers should be employed, such as microsatellites, which will enable to identify more precisely the genetic relationships among populations studied here, and possibly with populations of rivers where there are no dams, and may help future conservation actions in the rivers of Triângulo Mineiro.