Identification and characterization of repetitive DNA in the genus Didelphis Linnaeus, 1758 (Didelphimorphia, Didelphidae) and the use of satellite DNAs as phylogenetic markers.

Didelphis species have been shown to exhibit very conservative karyotypes, which mainly differ in their constitutive heterochromatin, known to be mostly composed by repetitive DNAs. In this study, we used genome skimming data combined with computational pipelines to identify the most abundant repetitive DNA families of Lutreolina crassicaudata and all six Didelphis species. We found that transposable elements (TEs), particularly LINE-1, endogenous retroviruses, and SINEs, are the most abundant mobile elements in the studied species. Despite overall similar TE proportions, we report that species of the D. albiventris group consistently present a less diverse TE composition and smaller proportions of LINEs and LTRs in their genomes than other studied species. We also identified four new putative satDNAs (sat206, sat907, sat1430 and sat2324) in the genomes of Didelphis species, which show differences in abundance and nucleotide composition. Phylogenies based on satDNA sequences showed well supported relationships at the species (sat1430) and groups of species (sat206) level, recovering topologies congruent with previous studies. Our study is one of the first attempts to present a characterization of the most abundant families of repetitive DNAs of Lutreolina and Didelphis species providing insights into the repetitive DNA composition in the genome landscape of American marsupials.

Bees and the Environmental Impact of the Rupture of the Fundão Dam.

The environmental consequences associated with the Fundão tailings dam failure in Mariana, Minas Gerais, Brazil on 5 November 2015 are still being investigated. Bees are the main pollinators believed to be most affected by the accident because they occur throughout the area affected by the dam rupture and build their nests in the soil. In this study, we evaluated the richness of different bee species in areas affected and not affected by the accident and measured the concentration of different metals on the pollen basket, or corbicula, located on the hind legs of Apis mellifera. Diversity indices were similar and there was no statistical difference in the diversity of bees sampled when comparing the sites affected and not affected by the tailings mud, either before or after the dam rupture. It is possible that the similarity is due to nearby forests that may be serving as areas of refuge. The levels of Al, Cu, Cd, Hg, and Pb in A. mellifera suggest no change in the level of metals in pollen collected by the bees that can be attributed to the rupture of the dam. Integr Environ Assess Manag 2020;16:631-635. © 2020 SETAC.

As consequências ambientais da ruptura da barragem de Fundão, ocorrida em Mariana, Minas Gerais, Brasil, em 5 de novembro de 2015, ainda estão sendo investigadas. As abelhas, principal grupo de polinizadores, podem ter sido afetadas direta e indiretamente, uma vez que a maioria das espécies constrói seus ninhos no solo. Neste estudo, avaliamos a riqueza de espécies de abelhas nas áreas afetadas e não afetadas e medimos a concentração de metais pesados nas corbículas de Apis mellifera, espécie que ocorre em toda a área afetada pela ruptura da barragem. Os índices de diversidade foram semelhantes e não houve diferença estatística na diversidade de abelhas amostradas quando comparamos locais afetados e não afetados pela lama de rejeitos após o rompimento da barragem. É possível que a semelhança se deva a florestas próximas que possam estar servindo como áreas de refúgio. Os resultados mostraram a presença de Al, Cu, Cd, Hg e Pb em A. mellifera. Nossos resultados indicam que não há efeito da contaminação de metais pesados nas abelhas devido à ruptura da barragem. Integr Environ Assess Manag 2020;16:631-635.