TMEM45A Is Dispensable for Epidermal Morphogenesis,Keratinization and Barrier Formation

TMEM45A gene encodes an initially uncharacterized predicted transmembrane protein. We previously showed that this gene is highly expressed in keratinocytes where its expression correlates with keratinization, suggesting a role in normal epidermal physiology. To test this hypothesis, we generated TMEM45A knockout mice and found that these mice develop without any evident phenotype. The morphology of the epidermis assessed by histology and by labelling differentiation markers in immunofluorescence was not altered. Toluidine blue permeability assay showed that the epidermal barrier develops normally during embryonic development. We also showed that depletion of TMEM45A in human keratinocytes does not alter their potential to form in vitro 3D-reconstructed epidermis. Indeed, epidermis with normal morphogenesis were generated from TMEM45A-silenced keratinocytes. Their expression of differentiation markers quantified by RT-qPCR and evidenced by immunofluorescence labelling as well as their barrier function estimated by Lucifer yellow permeability were similar to the control epidermis. In summary, TMEM45A gene expression is dispensable for epidermal morphogenesis, keratinization and barrier formation. If this protein plays a role in the epidermis, its experimental depletion can possibly be compensated by other proteins in the two experimental models analyzed in this study.     

There's no place like home: seedling mortality contributes to the habitat specialisation of tree species across Amazonia

Understanding the mechanisms generating species distributions remains a challenge, especially in hyperdiverse tropical forests. We evaluated the role of rainfall variation, soil gradients and herbivory on seedling mortality, and how variation in seedling performance along these gradients contributes to habitat specialisation. In a 4‐year experiment, replicated at the two extremes of the Amazon basin, we reciprocally transplanted 4638 tree seedlings of 41 habitat‐specialist species from seven phylogenetic lineages among the three most important forest habitats of lowland Amazonia. Rainfall variation, flooding and soil gradients strongly influenced seedling mortality, whereas herbivory had negligible impact. Seedling mortality varied strongly among habitats, consistent with predictions for habitat specialists in most lineages. This suggests that seedling performance is a primary determinant of the habitat associations of adult trees across Amazonia. It further suggests that tree diversity, currently mostly harboured in terra firme forests, may be strongly impacted by the predicted climate changes in Amazonia.     

RAD‐sequencing for estimating genomic relatedness matrix‐based heritability in the wild: A case study in roe deer

Estimating the evolutionary potential of quantitative traits and reliably predicting responses to selection in wild populations are important challenges in evolutionary biology. The genomic revolution has opened up opportunities for measuring relatedness among individuals with precision, enabling pedigree‐free estimation of trait heritabilities in wild populations. However, until now, most quantitative genetic studies based on a genomic relatedness matrix (GRM) have focused on long‐term monitored populations for which traditional pedigrees were also available, and have often had access to knowledge of genome sequence and variability. Here, we investigated the potential of RAD‐sequencing for estimating heritability in a free‐ranging roe deer (Capreolous capreolus) population for which no prior genomic resources were available. We propose a step‐by‐step analytical framework to optimize the quality and quantity of the genomic data and explore the impact of the single nucleotide polymorphism (SNP) calling and filtering processes on the GRM structure and GRM‐based heritability estimates. As expected, our results show that sequence coverage strongly affects the number of recovered loci, the genotyping error rate and the amount of missing data. Ultimately, this had little effect on heritability estimates and their standard errors, provided that the GRM was built from a minimum number of loci (above 7,000). Genomic relatedness matrix‐based heritability estimates thus appear robust to a moderate level of genotyping errors in the SNP data set. We also showed that quality filters, such as the removal of low‐frequency variants, affect the relatedness structure of the GRM, generating lower h² estimates. Our work illustrates the huge potential of RAD‐sequencing for estimating GRM‐based heritability in virtually any natural population.     

Algal Remodeling in a Ubiquitous Planktonic Photosymbiosis

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Comparative Analysis of Nucleotide Fluorescent Analogs for Registration of DNA Conformational Changes Induced by Interaction with Formamidopyrimidine-DNA Glycosylase Fpg

Russian Journal of Bioorganic Chemistry - DNA-substrates containing fluorescent DNA base analogs are widely used to study protein–nucleic acid interactions. In the case of DNA-recognizing...     

Neocortical Expansion Due to Increased Proliferation of Basal Progenitors Is Linked to Changes in Their Morphology

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The Influence of Hunting on Antipredator Behavior in Central African Monkeys and Duikers

Many animals can adjust their behavioral strategies to reduce predation risk. We investigated whether rain forest monkeys and duikers alter their antipredatory behavior in response to hunting by humans in southwestern Gabon. We compared monkey and duiker responses to human observers in an area where hunting is prohibited, to those in a nearby area where hunting pressure is moderate but spatially variable. The results of our study indicate that monkeys become more secretive when hunted, commencing alarm calls only when at a certain distance (typically > 50 m) from humans. We found no difference in monkey group size between hunted and no-hunting areas. In no-hunting areas, duikers often freeze in response to approaching observers, but in hunted areas they abandon this strategy and rapidly flee from humans. Duikers also whistle more often in areas where they are hunted frequently. Our findings have at least two important implications. First, behavioral observations of monkeys and duikers may be useful in gauging local hunting intensity in African rain forests. Second, duiker densities are likely to be overestimated in hunted areas, where they more readily flee and whistle, and underestimated in no-hunting areas, where they rely on freezing behavior to avoid detection. Because behavioral adaptations to hunting vary both among species and localities, these differences should be considered when attempting to derive population-density estimates for forest wildlife.