Unstable environment of coastal lagoons drives genetic variation in the amphipod Quadrivisio lutzi.

The freshwater/brackish amphipod Quadrivisio lutzi inhabits coastal lagoons, highly unstable environments subject to sudden inflow of marine water. Our aim was to evaluate how the genetic composition varies in these populations. Brazilian populations were compared by 16S rRNA and COI gene sequences. The genetic structure of four Rio de Janeiro amphipod populations was evaluated during the period of 2011-2019 by COI. Rio de Janeiro population was compared with Alagoas and São Paulo populations, which was genetically distinct, at species level (16S, d > 7%; COI, d >14%). The genetic structure in Rio de Janeiro showed the Imboassica subpopulation as the most divergent (Imboassica & Carapebus, F ST = 0.238), followed by Lagamar population (Lagamar & Carapebus, F ST = 0.049). The geographic distance and urbanization around these lagoons explain the degree of genetic isolation of these amphipod subpopulations. Paulista and Carapebus populations were not structured. Temporal variation in haplotype number and frequency were evident in both populations that were evaluated (Carapebus and Imboassica). Changes in salinity and water volume variation at these lagoons may be responsible for the observed changes in genetic composition, which may be the results of genetic drift effects over temporally fluctuating size subpopulations, without loss of genetic diversity.

Genotoxicity Biomonitoring Along a Coastal Zone Under Influence of Offshore Petroleum Exploration (Southeastern Brazil).

Offshore oil exploration creates threats to coastal ecosystems, including increasing urbanization and associated effluent releases. Genotoxicity biomarkers in mussels were determined across a gradient of coastal zone influences of offshore petroleum exploration in southeastern Brazil. Coastal ecosystems such as estuaries, beaches and islands were seasonally monitored for genotoxicity evaluation using the brown mussel Perna perna. The greatest DNA damage (5.2% ± 1.9% tail DNA and 1.5‰  ± 0.8‰ MN) were observed in urban estuaries, while Santana Archipelago showed levels of genotoxicity near zero and is considered a reference site. Mussels from urban and pristine beaches showed intermediate damage levels, but were also influenced by urbanization. Thus, mussel genotoxicity biomarkers greatly indicated the proposed oil exploration and urbanization scenarios that consequently are genetically affecting coastal organisms.

Successful amplification of mitochondrial DNA from dentin of the bottlenose dolphin Tursiops truncatus

Twenty-four teeth of Tursiops truncatus from the collection of the Marine Mammals Laboratory (FURG-RS) were analysed for their potential as DNA source for population genetic and taxonomic studies. All teeth were submitted to decontamination, grinding and demineralisation processes. Dentin powder was weighed for DNA extraction, which was evaluated by the amplification of two mitochondrial genes through PCR using universal primers. Cytochrome-b gene was amplified successfully. PCR products showed concentrations of 3-12 ng/µl for dentin powder, which was positively correlated to the quantity of dentin powder used for DNA extraction. To rule out contamination a SSCP was carried out including positive controls, and samples of humans involved in the analysis. The SSCP patterns for T. truncatus differed from all others, showing also polymorphism for the region. It was concluded that dentin was a good source of mtDNA for genetic studies in dolphins.

Vinte e quatro amostras de material dentário de Tursiops truncatus oriundas da coleção do Laboratório de Mamíferos Marinhos (FURG-RS) foram avaliadas para determinar seu potencial como fonte de DNA para estudos genético-populacionais e sistemáticos. Todos os dentes foram submetidos a processos de desinfecção, trituração e desmineralização. A dentina obtida foi pesada previamente à extração de DNA, a qual foi avaliada através da amplificação de dois genes mitocondriais, através da técnica de PCR (Reação em Cadeia da Polimerase), utilizando oligonucleotídeos iniciadores universais. Obteve-se sucesso apenas na amplificação do gene Citocromo-b. Destes produtos obtiveram-se concentrações de 3-12 ng/µl para o material dentário, observando-se uma relação linear positiva com a quantidade em gramas utilizada na extração de DNA. Com o objetivo de eliminar a possibilidade de contaminação foi realizada uma análise SSCP (Polimorfismo Conformacional de Fita Simples) incluindo os controles positivos e amostras de pessoas envolvidas nas análises. Os padrões SSCP de T. truncatus obtidos diferiram das outras amostras, observando-se polimorfismo na região para os exemplares de T. truncatus analisados. Concluiu-se que é possível obter DNA mitocondrial para estudos genético-populacionais e taxonômicos a partir de material dentário de golfinhos.