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Steep hybrid zones provide key insights into the mechanisms of speciation by reflecting incomplete reproductive isolation between diverging populations. However, the specific reproductive barriers preventing the fusion of such populations generally remain unclear, particularly the role of ecologically‐based divergent selection. To address the latter, we investigate a steep zone of transition between lake and inlet stream ecoty...
Interpretable deep learning reveals spatiotemporal MRI features of brain aging that align with neurodegenerationNARA Subscribed
Cortical thinning and atrophy are hallmarks of brain aging that have been characterized using magnetic resonance imaging (MRI). Brain aging involves many neuroanatomic features whose effects on brain structure remain unexplored. To address this challenge, we trained interpretable deep neural networks (DNNs) to estimate brain age (BA) from T 1 -weighted ( T 1 w) MRI. By identifying MRI features unapparent to humans, DNNs can fi...
Alzheimer’s disease (AD) disproportionately affects women and carriers of the apolipoprotein E ε4 allele (APOE4), yet little is known about how sex and APOE interact to influence white matter (WM) integrity during disease progression. We integrated diffusion MRI and matched blood transcriptomic data to investigate these interactions and their underlying biological mechanisms. WM microstructure was quantified using diffusion te...
Predicting the progression of MCI and Alzheimer’s disease on structural brain integrity and other features with machine learningNARA Subscribed
Machine learning (ML) on structural MRI data shows high potential for classifying Alzheimer’s disease (AD) progression, but the specific contribution of brain regions, demographics, and proteinopathy remains unclear. Using Alzheimer’s Disease Neuroimaging Initiative (ADNI) data, we applied an extreme gradient-boosting algorithm and SHAP (SHapley Additive exPlanations) values to classify cognitively normal (CN) older adults, th...
Populations must continuously respond to environmental change or risk extinction. These responses can be measured as phenotypic rates of change, which allow researchers to predict their contemporary evolutionary responses. In 1999, a database of phenotypic rates of change in wild populations was compiled. Since then, researchers have used (and expanded) this database to examine the phenotypic responses as a function of the fea...
Invasion of Pieris mannii butterflies across Central Europe facilitated by urbanizationNARA Subscribed
Urbanization progresses world-wide and the frequency of biological invasions increases. Understanding to what extent urban environments facilitate biological invasions and how this affects ecosystems within and outside urbanized areas thus becomes crucial. We here examine the role of urban environments in the invasion of the butterfly Pieris mannii that expanded across Central Europe within the last two decades. Using standard...
The maintenance of standing genetic variation: Gene flow vs. selective neutrality in Atlantic stickleback fishNARA Subscribed
Adaptation to derived habitats often occurs from standing genetic variation. The maintenance within ancestral populations of genetic variants favourable in derived habitats is commonly ascribed to long‐term antagonism between purifying selection and gene flow resulting from hybridization across habitats. A largely unexplored alternative idea based on quantitative genetic models of polygenic adaptation is that variants favoured...
Unraveling spatiotemporal variability of arbuscular mycorrhizal fungi in a temperate grassland plotNARA Subscribed
Summary Soils provide a heterogeneous environment varying in space and time; consequently, the biodiversity of soil microorganisms also differs spatially and temporally. For soil microbes tightly associated with plant roots, such as arbuscular mycorrhizal fungi (AMF), the diversity of plant partners and seasonal variability in trophic exchanges between the symbionts introduce additional heterogeneity. To clarify the impact of...
Widespread intersex differentiation across the stickleback genome – The signature of sexually antagonistic selection?NARA Subscribed
Females and males within a species commonly have distinct reproductive roles, and the associated traits may be under perpetual divergent natural selection between the sexes if their sex‐specific control has not yet evolved. Here, we explore whether such sexually antagonistic selection can be detected based on the magnitude of differentiation between the sexes across genome‐wide genetic polymorphisms by whole‐genome sequencing...
TRY plant trait database – enhanced coverage and open accessNARA Subscribed
Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodivers...
Meta‐analysis of chromosome‐scale crossover rate variation in eukaryotes and its significance to evolutionary genomicsNARA Subscribed
Understanding the distribution of crossovers along chromosomes is crucial to evolutionary genomics because the crossover rate determines how strongly a genome region is influenced by natural selection on linked sites. Nevertheless, generalities in the chromosome‐scale distribution of crossovers have not been investigated formally. We fill this gap by synthesizing joint information on genetic and physical maps across 62 animal,...
Genomics of adaptive divergence with chromosome‐scale heterogeneity in crossover rateNARA Subscribed
Genetic differentiation between divergent populations is often greater in chromosome centres than peripheries. Commonly overlooked, this broadscale differentiation pattern is sometimes ascribed to heterogeneity in crossover rate and hence linked selection within chromosomes, but the underlying mechanisms remain incompletely understood. A literature survey across 46 organisms reveals that most eukaryotes indeed exhibit a reduce...
Parallel adaptation is common and may often occur from shared genetic variation, but the genomic consequences of this process remain poorly understood. We first use individual‐based simulations to demonstrate that comparisons between populations adapted in parallel to similar environments from shared variation reveal a characteristic genomic signature around a selected locus: a low‐divergence valley centred at the locus and fl...
Heterogeneity in recombination rate may strongly influence genome evolution and entail methodological challenges to genomic investigation. Nevertheless, a solid understanding of these issues awaits detailed information across a broad range of taxa. Based on 282 F 2 individuals and 1872 single nucleotide polymorphisms, we characterize recombination in the threespine stickleback fish genome. We find an average genome‐wide recomb...
Genome divergence during evolutionary diversification as revealed in replicate lake–stream stickleback population pairsNARA Subscribed
Evolutionary diversification is often initiated by adaptive divergence between populations occupying ecologically distinct environments while still exchanging genes. The genetic foundations of this divergence process are largely unknown and are here explored through genome scans in multiple independent lake–stream population pairs of threespine stickleback. We find that across the pairs, overall genomic divergence is associate...
Human DimensionsNARA Subscribed
12The University of MD Extension (UME) has been very effective in teaching forest landowners concepts and principles of forest management through seminars, workshops and field days. After evaluating these techniques and recognizing people learn differently, new delivery methods were developed. UME developed a landowner based forestry correspondence course in two formats, first a traditional paper then a web based version. Thes...
Constraints on speciation suggested by comparing lake‐stream stickleback divergence across two continentsNARA Subscribed
Adaptation to ecologically distinct environments can coincide with the emergence of reproductive barriers. The outcome of this process is highly variable and can range along a continuum from weak population differentiation all the way to complete, genome‐wide divergence. The factors determining how far diverging taxa will move along this continuum remain poorly understood but are most profitably investigated in taxa under repl...
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