Contrasting patterns of RUNX2 repeat variations are associated with palate shape in phyllostomid bats and New World primates.

Establishing the genetic basis that underlies craniofacial variability in natural populations is one of the main topics of evolutionary and developmental studies. One of the genes associated with mammal craniofacial variability is RUNX2, and in the present study we investigated the association between craniofacial length and width and RUNX2 across New World bats (Phyllostomidae) and primates (Catarrhini and Platyrrhini). Our results showed contrasting patterns of association between the glutamate/alanine ratios (Q/A ratio) and palate shape in these highly diverse groups. In phyllostomid bats, we found an association between shorter/broader faces and increase of the Q/A ratio. In New World monkeys (NWM) there was a positive correlation of increasing Q/A ratios to more elongated faces. Our findings reinforced the role of the Q/A ratio as a flexible genetic mechanism that would rapidly change the time of skull ossification throughout development. However, we propose a scenario in which the influence of this genetic adjustment system is indirect. The Q/A ratio would not lead to a specific phenotype, but throughout the history of a lineage, would act along with evolutionary constraints, as well as other genes, as a facilitator for adaptive morphological changes.

Molecular detection of fungi of public health importance in wild animals from Southern Brazil.

Some animals have an important relationship with fungal infections, and searching for pathogens in animal samples may be an opportunity for eco-epidemiological research. Since studies involving wildlife are generally restricted, using samples from road kills is an alternative. The aim of this study was to verify whether pathogenic fungi of public health importance occur in wildlife road kills from Santa Catarina State, Brazil. Organ samples (n = 1063) from 297 animals were analysed according to Polymerase Chain Reaction (PCR) using universal primers to detect fungi in general and, subsequently, using primers specific to Paracoccidioides brasiliensis, Histoplasma capsulatum and Cryptococcus spp. There were 102 samples positive for fungal species. Eight samples were positive for P. brasiliensis, three samples were positive for Cryptococcus spp. and one sample had coinfection by these two fungi. No sample was positive for Histoplasma spp. according to the molecular detection. Genetic sequencing allowed the identification of Fungal sp. in 89 samples, Cryptococcus neoformans in two samples and Aspergillus penicillioides in three samples. This study shows the importance of wild animals in the epidemiology of fungal infections and assists in the mapping of pathogen occurrence in a region that was not previously evaluated.

Pleistocene climatic oscillations in Neotropical open areas: Refuge isolation in the rodent Oxymycterus nasutus endemic to grasslands.

Pleistocene climatic oscillations favoured the expansion of grassland ecosystems and open vegetation landscapes throughout the Neotropics, and influenced the evolutionary history of species adapted to such environments. In this study, we sampled populations of the rodent Oxymycterus nasutus endemic to open areas in the Pampas and Atlantic Forest biomes to assess the tempo and mode of population divergence using an integrative approach, including coalescence theory, ecological niche models, and morphometry. Our results indicated that these O. nasutus populations exhibited high levels of genetic structure. Six major mtDNA clades were found, structuring these biomes into distinct groups. Estimates of their divergence times was indicated to be 0.571 myr. The high degree of genetic structure is reflected in the analyses of geometric morphometric; skull differences between lineages in the two ecoregions were detected. During the last glacial maximum, there was a strong increase in suitable abiotic conditions for O. nasutus. Distinct molecular markers revealed a population expansion over time, with a possible demographic retraction during the post-glacial period. Considering that all clades coalesce with the last interglacial maximum, our results indicated that reduction in suitable conditions during this period may have resulted in a possible vicariance associated with refuge isolation.

DNA barcoding of sigmodontine rodents: identifying wildlife reservoirs of zoonoses.

Species identification through DNA barcoding is a tool to be added to taxonomic procedures, once it has been validated. Applying barcoding techniques in public health would aid in the identification and correct delimitation of the distribution of rodents from the subfamily Sigmodontinae. These rodents are reservoirs of etiological agents of zoonoses including arenaviruses, hantaviruses, Chagas disease and leishmaniasis. In this study we compared distance-based and probabilistic phylogenetic inference methods to evaluate the performance of cytochrome c oxidase subunit I (COI) in sigmodontine identification. A total of 130 sequences from 21 field-trapped species (13 genera), mainly from southern Brazil, were generated and analyzed, together with 58 GenBank sequences (24 species; 10 genera). Preliminary analysis revealed a 9.5% rate of misidentifications in the field, mainly of juveniles, which were reclassified after examination of external morphological characters and chromosome numbers. Distance and model-based methods of tree reconstruction retrieved similar topologies and monophyly for most species. Kernel density estimation of the distance distribution showed a clear barcoding gap with overlapping of intraspecific and interspecific densities < 1% and 21 species with mean intraspecific distance < 2%. Five species that are reservoirs of hantaviruses could be identified through DNA barcodes. Additionally, we provide information for the description of a putative new species, as well as the first COI sequence of the recently described genus Drymoreomys. The data also indicated an expansion of the distribution of Calomys tener. We emphasize that DNA barcoding should be used in combination with other taxonomic and systematic procedures in an integrative framework and based on properly identified museum collections, to improve identification procedures, especially in epidemiological surveillance and ecological assessments.