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Optimization of protocols for DNA extraction from fecal samples

High-throughput sequencing offers new possibilities in molecular ecology and conservation studies. However, its potential has not yet become fully exploited for noninvasive studies of free–ranging animals, such as those based on feces. High–throughput sequencing allows sequencing of short DNA fragments and could allow simultaneous genotyping of a very large number of samples and markers at a low cost. The application of high throughput genotyping to fecal samples from wildlife has been hindered by several labor intensive steps. Alternative protocols which could allow higher throughput were evaluated for two of these steps: sample collection and DNA extraction. Two different field sampling and seven different DNA extraction methods were tested on grey wolf (Canis lupus) feces. There was high variation in genotyping success rates. The field sampling method based on surface swabbing performed much worse than the extraction from a fecal fragment. In addition, there is a lot of room for improvement in the DNA extraction step. Optimization of protocols can lead to very much more efficient, cheaper and higher throughput noninvasive monitoring. Selection of appropriate markers is still of paramount importance to increase genotyping success. informacion[at] Sarabia et al (2020) Towards high-throughput analyses of fecal samples from wildlife. Animal Biodiver Conserv 43.2: 271–283 Doi 10.32800/abc.2020.43.0271
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Ecological determinants of avian malaria infections

Ecological determinants of avian malaria infections

Vector and host communities, as well as habitat characteristics, may have important but different impacts on the prevalence, richness and evenness of vector-borne parasites. Here, the relative importance of (1) the mosquito community composition, (2) the vertebrate community composition and (3) landscape characteristics on the prevalence, richness and evenness of avian Plasmodium are investigated. Authors hypothesized that parasite prevalence will be more affected by vector-related parameters, while host parameters should be also important to explain Plasmodium richness and evenness. 2,588 wild house sparrows (Passer domesticus) and 340,829 mosquitoes were sampled, and vertebrate censuses at 45 localities in the Southwest of Spain were performed. These localities included urban, rural and natural landscapes that were characterized by several habitat variables. Twelve Plasmodium lineages were identified in house sparrows corresponding to three major clades. Variation partitioning showed that landscape characteristics explained the highest fraction of variation in all response variables. Plasmodium prevalence was in addition explained by vector-related variables and its interaction with landscape. Parasite richness and evenness were mostly explained by vertebrate community-related variables. The structuring role of landscape characteristics in vector and host communities was a key factor in determining parasite prevalence, richness and evenness, although the role of each factor differed according to the parasite parameters studied. These results show that the biotic and abiotic contexts are important to explain the transmission dynamics of mosquito-borne pathogens in the wild. informacion[at] Ferraguti et al (2018) Ecological determinants of avian malaria infections: an integrative analysis at landscape, mosquito and vertebrate community levels. J Anim Ecol DOI: 10.1111/1365-2656.12805