Biology subjects

Reid, N.

Publications and source records attributed to Reid, N..

6 recordsLinked to original sources

bioRxiv2025

Rapid genome-wide introgression reveals fitness advantage of immigrant genotypes

Evolutionary biology has long recognized the tendency for populations to be locally adapted to their ancestral habitat, resulting in higher resident fitness. However, immigrants can also introduce beneficial alleles. The resulting adaptive introgression is usually inferred retrospectively, rather than as a contemporary process. Here, we document exceptionally rapid ongoing adaptive introgression in a lake population of threespine stickleback (Gasterosteus aculeatus). In the first generations after a discrete immigration event, all chromosomes exhibited large increases in immigrant ancestry due to linkage disequilibrium. After a decade, the extent of introgression varied across the genome. The fastest-evolving genes included Spi1b, which enables an increased fibrosis defense against a previously common tapeworm, whose prevalence then declined dramatically. This case study highlights the capacity for immigration to supply beneficial alleles that drive rapid genome-wide evolution.

evolutionary biology↗

bioRxiv2025

Mink by mink: stitching together signatures of subspecies adaptation through a pangenome of threatened mustelids

The American mink (Neogale vison), a semi-aquatic Mustelidae carnivoran with broad ecological range across North America, includes several putative subspecies of conservation concern. To investigate the evolutionary history and adaptive signatures of mink subspecies, chromosome-scale genome assemblies were generated for six individuals representing three southern subspecies: N. vison evergladensis, N. vison vulgivaga, and N. vison lutensis. Genomes were assembled using Illumina short reads, scaffolded with Oxford Nanopore long reads, and aligned to the phased N. vison reference genome. Assemblies ranged from 75.9% to 97.8% completeness, with five meeting thresholds for pangenome construction. A reference-free pangenome revealed an open architecture, highlighting considerable subspecies diversity. Subspecies-specific gene enrichment reflected adaptation: N. vison evergladensis showed enrichment in traits related to reproduction and sensory function; N. vison vulgivaga in cytoskeletal remodeling and oxidative stress; and N. vison lutensis in neuronal development, synaptic plasticity and cellular stress pathways. Assessment of the mitogenomes resolved N. vison lutensis as a distinct lineage, while nuclear data supported broader subspecies divergence but lacked fine scale resolution. N. vison evergladensis showed multiple signatures of small population size, including inbreeding coefficients (FROH) above 0.5, and displayed consistent population decline over time via demographic inference. Our findings support evergladensis as a distinct subspecies, supported by both the mitogenome phylogeny, and significant functional differentiation. As the first pangenome for Mustelidae, this study demonstrates the power of integrating cross-platform sequencing with natural history specimens to improve the resolution on signatures of adaptation and inform conservation policy and management of threatened populations.

genomics↗

bioRxiv2024

Constitutive differences in immune gene expression and energy storage phenotypes co-vary with winter environment in wood frogs

Many terrestrial ectotherms have gone to great evolutionary lengths to adapt to long cold winters; some have even evolved the ability to tolerate the freezing of most of the water in the body. Now, however, high-elevation, and high-latitude winters are experiencing an accelerated period of warming. Specialized winter adaptations that promoted fitness in a seasonally frozen environment may soon be superfluous or even maladaptive. We ask whether winter adaptations include changes in immune functions, and whether changing winter conditions could exert disparate effects on populations of a wide-ranging terrestrial ectotherm, the wood frog (Lithobates sylvaticus). By rearing wood frogs from ancestral winter environments that vary in length and temperature in a common garden, and reciprocally exposing post-metamorphic frogs to unfrozen and frozen artificial winter conditions in the lab, we were able to decompose transcriptomic differences in ventral skin gene expression into those that were environmentally induced (responsive to temperature), genetically determined, and those that varied as an interaction between genotype and environment. We found that frogs from harsh ancestral winter environments constitutively upregulated immune processes, including cellular immunity, inflammatory processes, and adaptive immune processes, as compared to frogs from mild ancestral winter environments. Further, we saw that expression of several genes varied in an interaction between genotype and artificial winter. We suggest that just as winter climates likely served as the selective force resulting in remarkable winter adaptations such as freeze tolerance, they also induced constitutive changes in immune gene expression.

evolutionary biology↗

bioRxiv2024

Reduction of Deformed Wing Virus-B levels in Colonies of the Honey bee Apis mellifera after Queen Vaccination with inactivated Paenibacillus larvae

Deformed wing virus (DWV) is a virulent and ubiquitous disease that affects honey bee colonies. DWV infects bees at all life stages, but is most noticeable in adult bees, where clinical symptoms include shriveled, non-functional wings, and a drastically shortened lifespan. DWV is recorded in upwards of 90% of honey bee colonies worldwide, and has been linked to colony loss in symptomatic hives. DWV is primarily spread by Varroa destructor mites, who feed on the fat bodies of honey bee adults and pupae. There is currently no direct treatment or preventative for DWV, with the primary method of reduction being vector control using acaracides. In this study, we tested the effect that vaccinating honey bee queens using killed Paenibacillus larvae bacterin, the causative agent of the honey bee disease American Foulbrood, had on deformed wing virus load in honey bee colonies. We placed vaccinated queens in 200 honey bee colonies, and unvaccinated queens in 200 colonies, and measured quantities of DWV-B in both groups immediately before, and 4 months after vaccination. We found that levels of DWV-B were identical before vaccination, but were significantly reduced in colonies 4 months post vaccination. This change was found despite no difference in mite quantities between groups. Overall, these data provide evidence that vaccination of queens with P. larvae bacterin is an effective method for reduction of DWV-B quantities in honey bee colonies in a commercially relevant field setting.

immunology↗

bioRxiv2023

Spatial-extent inference for testing variance components in reliability and heritability studies

Clusterwise inference is a popular approach in neuroimaging to increase sensitivity, but most existing methods are currently restricted to the General Linear Model (GLM) for testing mean parameters. Statistical methods for testing variance components, which are critical in neuroimaging studies that involve estimation of narrow-sense heritability or test-retest reliability, are underdeveloped due to methodological and computational challenges, which would potentially lead to low power. We propose a fast and powerful test for variance components called CLEAN-V (CLEAN for testing Variance components). CLEAN-V models the global spatial dependence structure of imaging data and computes a locally powerful variance component test statistic by data-adaptively pooling neighborhood information. Correction for multiple comparisons is achieved by permutations to control family-wise error rate (FWER). Through analysis of task-fMRI data from the Human Connectome Project across five tasks and comprehensive data-driven simulations, we show that CLEAN-V outperforms existing methods in detecting test-retest reliability and narrow-sense heritability with significantly improved power, with the detected areas aligning with activation maps. The computational efficiency of CLEAN-V also speaks of its practical utility, and it is available as an R package.

neuroscience↗

bioRxiv2021

The evolutionary pathways for local adaptation in mountain hares

Understanding the evolution of local adaptations is a central aim of evolutionary biology and key for the identification of unique populations and lineages of conservation relevance. By combining RAD sequencing and whole-genome sequencing, we identify genetic signatures of local adaptation in mountain hares (Lepus timidus) from isolated and distinctive habitats of its wide distribution: Ireland, the Alps and Fennoscandia. Demographic modelling suggested that the split of these mountain hares occurred around 20 thousand years ago, providing the opportunity to study adaptive evolution over a short timescale. Using genome-wide scans, we identified signatures of extreme differentiation among hares from distinct geographic areas that overlap with area-specific selective sweeps, suggesting targets for local adaptation. Several identified candidate genes are associated with traits related to the uniqueness of the different environments inhabited by the three groups of mountain hares, including coat colour, ability to live at high altitudes and variation in body size. In Irish mountain hares, a variant of ASIP, a gene previously implicated in introgression-driven winter coat colour variation in mountain and snowshoe hares (L. americanus), may underlie brown winter coats, reinforcing the repeated nature of evolution at ASIP moulding adaptive seasonal colouration. Comparative genomic analyses across several hare species suggested that mountain hares adaptive variants appear predominantly species-specific. However, using coalescent simulations we also show instances where the candidate adaptive variants have been introduced via introgressive hybridization. Our work shows that standing adaptive variation, including that introgressed from other species, was a crucial component of the post-glacial dynamics of species.

evolutionary biology↗