Biology subjects

Wolf, S. E.

Publications and source records attributed to Wolf, S. E..

6 recordsLinked to original sources

bioRxiv2026

Wild wood mouse gut microbiota are influenced by captivity and cross-fostering

Background Wild and laboratory animals harbour profoundly different gut microbiota, but how microbiomes shift between these states, and the relative roles of captivity, microbial history, and host identity in shaping that shift, remain unclear. Here, we developed a unique wood mouse (Apodemus sylvaticus) system comprising free-living mice (Wild:As), a wild-derived colony maintained in captivity for over a decade (Wild-like:As), and a second colony that we generated from the Wild-like:As mice by caesarean rederivation and cross-fostering to laboratory Mus musculus (Lab-like:As). We compared these three Apodemus cohorts with conventional laboratory Mus musculus (Lab:Mm) to ask how microbial diversity, community composition, and functional potential vary across a spectrum of wild-to-laboratory conditions. Results We found that alpha diversity varied substantially among cohorts but showed no consistent wild-to-laboratory trend: Shannon diversity was higher in Lab:Mm and Lab-like:As than in Wild:As and Wild-like:As mice, whereas phylogenetic diversity was similarly high in both the Wild:As and Lab:Mm groups. Community composition more closely reflected cohort histories. Despite over a decade in captivity, Wild-like:As mice remained most similar to Wild:As conspecifics, whereas Lab-like:As mice shifted strongly away from Wild-like:As and toward, but remained distinct from, Lab:Mm mice. The clearest wild-to-laboratory pattern emerged in microbiome consistency: core ASVs (present in [≥]90% of individuals) increased from 9 in Wild:As to 46 in Wild-like:As, 72 in Lab-like:As, and 138 in Lab:Mm mice. Predicted functional potential revealed a further distinction between taxonomic and functional patterns: Wild:As and Wild-like:As microbiomes did not differ significantly, whereas Lab-like:As shifted toward the Lab:Mm state despite remaining taxonomically distinct. Conclusions Together, these results show that laboratory-associated microbiomes do not emerge through simple loss of wild microbial diversity, but through broader reorganisation of community composition, consistency, and predicted functional potential reflecting microbial history and host context. The persistent Wild-like and Lab-like microbiome states within Apodemus provide a powerful experimental system for future timely work testing how microbiome history influences host physiology, resilience, and responses to environmental challenges.

microbiology↗

bioRxiv2025

Reducing food stress and parasitism may have unexpected consequences on faecal corticosterone in a wild rodent

In wild animals, glucocorticoid hormones play a key role in responses to environmental stressors and the maintenance of homeostasis, allocating energy between energy-demanding processes. Although acute rises in glucocorticoids are beneficial for short-term survival, prolonged exposure can be detrimental to reproduction and survival. Thus, understanding the factors driving glucocorticoid concentrations is crucial for understanding key processes in ecology and evolution. Here, we examined how manipulation of two environmental stressors - food availability and parasite burden, influence levels of faecal corticosterone in a wild population of wood mice (Apodemus sylvaticus). To do so, we experimentally altered nutrition via food supplementation and reduced gastrointestinal nematode infection by anthelmintic treatment, using Heligmosomoides polygyrus as an indicator of treatment efficacy. Faecal corticosterone was not found to be impacted by food supplementation or anthelminthic treatment. However, our results may be mediated by variation in resource availability or masked by other factors that affect corticosterone. For example, corticosterone declined seasonally and was higher in adult, female mice. While we expected higher food availability and lower worm burden to decrease stress, putatively higher rates of reproduction in food supplemented areas could neutralise any decreases in corticosterone associated with alleviation of food and parasite stress. Thus, alleviating stress in the wild may have unintended consequences on fitness.

evolutionary biology↗

bioRxiv2025

A DNA methylation-based clock for age estimates in the wood mouse (Apodemus sylvaticus)

Environmental stressors are expected to accelerate senescence but demonstrating this requires both a measure of senescence and knowledge of chronological age - data rarely available for most wild animals. Here, we constructed a DNA methylation-based epigenetic clock for the wood mouse (Apodemus sylvaticus) using known-aged laboratory individuals and applied it to a wild population of unknown ages. This represents one of the first demonstrations that a laboratory-trained epigenetic clock can be used to infer age structure in free-living animals. Multiple lines of evidence validated use of the clock in wild individuals: age estimates fell within expected ranges, recapitulated population demographic structure, and recovered predicted signatures of senescence, including an increase in infection probability with age. Moreover, wild mice given experimental food supplementation and parasite-removal drugs exhibited slower epigenetic ageing rates. Together, our findings demonstrate that epigenetic clocks can infer both chronological age and ageing rates in the wild, providing a powerful framework to identify the ecological and individual determinants of ageing.

genomics↗

bioRxiv2024

Phylotranscriptomics reveals convergent behavioral evolution associated with shared and unique mechanisms in cavity-nesting songbirds

Uncovering the genomic bases of phenotypic adaptation is a major goal in biology, but this has been hard to achieve for complex behavioral traits. Here, we leverage the repeated, independent evolution of obligate cavity-nesting in birds to test the hypothesis that pressure to compete for a limited breeding resource has facilitated convergent evolution in behavior, hormones, and gene expression. We used an integrative approach, combining aggression assays in the field, testosterone measures, and transcriptome-wide analyses of the brain in wild-captured females and males. Our experimental design compared species pairs across five avian families, each including one obligate cavity-nesting species and a related species with a more flexible nest strategy. We find behavioral convergence, with higher levels of territorial aggression in obligate cavity-nesters, particularly among females. Across species, levels of testosterone in circulation were not associated with nest strategy, nor aggression. Phylogenetic analyses of individual genes and co-regulated gene networks revealed more shared patterns of brain gene expression than expected by drift, but the scope of convergent gene expression evolution was limited to a small percent of the genome. When comparing our results to other studies that did not use phylogenetic methods, we suggest that accounting for shared evolutionary history may reduce the number of genes inferred as convergently evolving. Altogether, we find that behavioral convergence in response to shared ecological pressures is associated with largely independent gene expression evolution across different avian families, punctuated by a narrow set of convergently evolving genes.

evolutionary biology↗

bioRxiv2023

Cross-tissue comparison of telomere length and quality metrics of DNA among individuals aged 8 to 70 years

Telomere length (TL) is an important biomarker of cellular aging, yet its links with health outcomes may be complicated by use of different tissues. We evaluated within- and between-individual variability in TL and quality metrics of DNA across five tissues using a cross-sectional dataset ranging from 8 to 70 years (N=197). DNA was extracted from all tissue cells using the Gentra Puregene DNA Extraction Kit. Absolute TL (aTL) in kilobase pairs was measured in buccal epithelial cells, saliva, dried blood spots (DBS), buffy coat, and peripheral blood mononuclear cells (PBMCs) using qPCR. aTL significantly shortened with age for all tissues except saliva and buffy coat, although buffy coat was available for a restricted age range (8 to 15 years). aTL did not significantly differ across blood-based tissues (DBS, buffy coat, PBMC), which had significantly longer aTL than buccal cells and saliva. Additionally, aTL was significantly correlated for the majority of tissue pairs, with partial Spearmans correlations controlling for age and sex ranging from = 0.18 to 0.51. We also measured quality metrics of DNA including integrity, purity, and quantity of extracted DNA from all tissues and explored whether controlling for DNA metrics improved predictions of aTL. We found significant tissue variation: DNA from blood-based tissues had high DNA integrity, more acceptable A260/280 and A260/230 values, and greater extracted DNA concentrations compared to buccal cells and saliva. Longer aTL was associated with lower DNA integrity, higher extracted DNA concentrations, and higher A260/230, particularly for saliva. Model comparisons suggested that incorporation of quality DNA metrics improves models of TL, although relevant metrics vary by tissue. These findings highlight the merits of using blood-based tissues and suggest that incorporation of quality DNA metrics as control variables in population-based studies can improve TL predictions, especially for more variable tissues like buccal and saliva.

genomics↗

bioRxiv2021

The telomere regulatory gene POT1 responds to stress and predicts performance in nature: implications for telomeres and life history evolution

Long telomeres have become nearly synonymous with a variety of fitness-related traits and may be mediators of ecologically relevant variation in life history strategies. Growing evidence suggests that telomere dynamics are more predictive of performance than length itself, but very little work considers how telomere regulatory mechanisms respond to environmental challenges or influence performance in nature. Here, we combine observational and experimental datasets from free-living tree swallows (Tachycineta bicolor) to assess how performance is predicted by the telomere regulatory gene POT1, which encodes a shelterin protein that sterically blocks telomerase from repairing the telomere. First, we show that lower POT1 gene expression was associated with higher female quality, i.e. earlier breeding, and heavier body mass. We next challenged mothers with an immune stressor (lipopolysaccharide injection) that led to sickness in mothers and 24h of food restriction in their offspring. While POT1 did not respond to maternal injection, females with lower constitutive gene expression were better able to maintain feeding rates following treatment. Maternal injection also generated a one-day stressor for chicks, who responded with decreased POT1 gene expression and elongated telomeres. Other putatively stress-responsive mechanisms (i.e. glucocorticoids, antioxidants) were not significantly different between control and stress-exposed chicks. Model comparisons indicated that POT1 mRNA abundance was a largely better predictor of performance than telomere dynamics, indicating that telomere regulators may be powerful modulators of variation in life history strategies.

molecular biology↗