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Melton McKenna posted an update 22 hours, 55 minutes ago
Plant pests and diseases impact both food security and natural ecosystems, and the impact has been accelerated in recent years due to several confounding factors. The globalisation of trade has moved pests out of natural ranges, creating damaging epidemics in new regions. Climate change has extended the range of pests and the pathogens they vector. Resistance to agrochemicals has made pathogens, pests, and weeds more difficult to control. Early detection is critical to achieve effective control, both from a biosecurity as well as an endemic pest perspective. Molecular diagnostics has revolutionised our ability to identify pests and diseases over the past two decades, but more recent technological innovations are enabling us to achieve better pest surveillance. In this review, we will explore the different technologies that are enabling this advancing capability and discuss the drivers that will shape its future deployment.Understanding how selection shapes population differentiation and local adaptation in marine species remains one of the greatest challenges in the field of evolutionary biology. The selection of genes in response to environment-specific factors and microenvironmental variation often results in chaotic genetic patchiness, which is commonly observed in rocky shore organisms. To identify these genes, the expression profile of the marine gastropod Littoraria flava collected from four Southeast Brazilian locations in ten rocky shore sites was analyzed. In this first L. flava transcriptome, 250,641 unigenes were generated, and 24% returned hits after functional annotation. Independent paired comparisons between 1) transects, 2) sites within transects, and 3) sites from different transects were performed for differential expression, detecting 8,622 unique differentially expressed genes. Araçá (AR) and São João (SJ) transect comparisons showed the most divergent gene products. For local adaptation, fitness-related differentially expressed genes were chosen for selection tests. Nine and 24 genes under adaptative and purifying selection, respectively, were most related to biomineralization in AR and chaperones in SJ. The biomineralization-genes perlucin and gigasin-6 were positively selected exclusively in the site toward the open ocean in AR, with sequence variants leading to pronounced protein structure changes. Despite an intense gene flow among L. flava populations due to its planktonic larva, gene expression patterns within transects may be the result of selective pressures. Our findings represent the first step in understanding how microenvironmental genetic variation is maintained in rocky shore populations and the mechanisms underlying local adaptation in marine species.Specific fat distributions are risk factors for complex diseases, including coronary heart disease and obstructive sleep apnea. To demonstrate the utility of high-diversity mouse models for elucidating genetic associations, we describe the phenotyping and heritability of fat distributions within the five classical inbred and three wild-derived founder mouse strains of the Collaborative Cross and Diversity Outbred mice. Measurements of subcutaneous and internal fat volumes in the abdomen, thorax and neck, and fat volumes in the tongue and pericardium were obtained using magnetic resonance imaging in male mice from the A/J (n = 12), C57BL/6J (n = 17), 129S1/SvlmJ (n = 12), NOD/LtJ (n = 14), NZO/HILtJ (n = 12), CAST/EiJ (n = 14), PWK/PhJ (n = 12), and WSB/EiJ (n = 15) strains. Phenotypes were compared across strains using analysis of variance and heritability estimated as the proportion of phenotypic variability attributable to strain. Heritability ranged from 44 to 91% across traits, including >70% heritability of tongue fat. A majority of heritability estimates remained significant controlling for body weight, suggesting genetic influences independent of general obesity. Principal components analysis supports genetic influences on overall obesity and specific to increased pericardial and intra-neck fat. Thus, among the founder strains of the Collaborative Cross and Diversity Outbred mice, we observed significant heritability of subcutaneous and internal fat volumes in the neck, thorax and abdomen, pericardial fat volume and tongue fat volume, consistent with genetic architecture playing an important role in explaining trait variability. Findings pave the way for studies utilizing high-diversity mouse models to identify genes affecting fat distributions and, in turn, influencing risk for associated complex disorders.Compared with asexual reproduction, sex facilitates the transmission of transposable elements (TEs) from one genome to another, but boosts the efficacy of selection against deleterious TEs. Thus, theoretically, it is unclear whether sex has a positive net effect on TE’s proliferation. An empirical study concluded that sex is at the root of TE’s evolutionary success because the yeast TE load was found to decrease rapidly in approximately 1,000 generations of asexual but not sexual experimental evolution. However, this finding contradicts the maintenance of TEs in natural yeast populations where sexual reproduction occurs extremely infrequently. Here, we show that the purported TE load reduction during asexual experimental evolution is likely an artifact of low genomic sequencing coverages. We observe stable TE loads in both sexual and asexual experimental evolution from multiple yeast data sets with sufficient coverages. To understand the evolutionary dynamics of yeast TEs, we turn to asexual mutation accumulation lines that have been under virtually no selection. We find that both TE transposition and excision rates per generation, but not their difference, tend to be higher in environments where yeast grows more slowly. DEG-35 purchase However, the transposition rate is not significantly higher than the excision rate and the variance of the TE number among natural strains is close to its neutral expectation, suggesting that selection against TEs is at best weak in yeast. We conclude that the yeast TE load is maintained largely by a transposition-excision balance and that the influence of sex remains unclear.