Studies of species that experience environmental heterogeneity across their distributions have become an important tool for understanding mechanisms of adaptation and predicting responses to climate change. We examine population structure, demographic history and environmentally associated genomic variation in
- Award ID(s):
- 1921585
- NSF-PAR ID:
- 10171881
- Date Published:
- Journal Name:
- G3
- ISSN:
- 2160-1836
- Page Range / eLocation ID:
- g3.401437.2020
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Bombus vosnesenskii , a common bumble bee in the western USA, using whole genome resequencing of populations distributed across a broad range of latitudes and elevations. We find thatB. vosnesenskii exhibits minimal population structure and weak isolation by distance, confirming results from previous studies using other molecular marker types. Similarly, demographic analyses with Sequentially Markovian Coalescent models suggest that minimal population structure may have persisted since the last interglacial period, with genomes from different parts of the species range showing similar historical effective population size trajectories and relatively small fluctuations through time. Redundancy analysis revealed a small amount of genomic variation explained by bioclimatic variables. Environmental association analysis with latent factor mixed modelling (LFMM2) identified few outlier loci that were sparsely distributed throughout the genome and although a few putative signatures of selective sweeps were identified, none encompassed particularly large numbers of loci. Some outlier loci were in genes with known regulatory relationships, suggesting the possibility of weak selection, although compared with other species examined with similar approaches, evidence for extensive local adaptation signatures in the genome was relatively weak. Overall, results indicateB. vosnesenskii is an example of a generalist with a high degree of flexibility in its environmental requirements that may ultimately benefit the species under periods of climate change. -
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Abstract Understanding evolutionary responses to variation in temperature and precipitation across species ranges is of fundamental interest given ongoing climate change. The importance of temperature and precipitation for multiple aspects of bumble bee (
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Ware, Jessica (Ed.)Abstract Broadly distributed species experience divergent abiotic conditions across their ranges that may drive local adaptation. Montane systems where populations are distributed across both latitudinal and elevational gradients are especially likely to produce local adaptation due to spatial variation in multiple abiotic factors, including temperature, oxygen availability, and air density. We use whole-genome resequencing to evaluate the landscape genomics of Bombus vancouverensis Cresson (Hymenoptera: Apidae), a common montane bumble bee that is distributed throughout the western part of North America. Combined statistical approaches revealed several large windows of outlier SNPs with unusual levels of differentiation across the region and indicated that isothermality and elevation were the environmental features most strongly associated with these variants. Genes found within these regions had diverse biological functions, but included neuromuscular function, ion homeostasis, oxidative stress, and hypoxia that could be associated with tolerance of temperature, desiccation, or high elevation conditions. The whole-genome sequencing approach revealed outliers occurred in genome regions with elevated linkage disequilibrium, elevated mean FST, and low intrapopulation nucleotide diversity. Other kinds of structural variations were not widely associated with environmental predictors but did broadly match geographic separation. Results are consistent with other studies suggesting that regions of low recombination may harbor adaptive variation in bumble bees within as well as between species and refine our understanding of candidate genes that could be further investigated as possible targets of selection across the B. vancouverensis range.more » « less
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1534/g3.120.401437
