scholarly journals Misalignment of selection, plasticity, and among-individual variation: A test of theoretical predictions with Peromyscus maniculatus.

2020 ◽  
Author(s):  
Monica Anderson Berdal ◽  
Ned A Dochtermann

Genetic variation and phenotypic plasticity are predicted to align with selection surfaces, a prediction that has rarely been empirically tested. Understanding the relationship between sources of phenotypic variation, i.e. genetic variation and plasticity, with selection surfaces improves our ability to predict a population's ability to adapt to a changing environment and our understanding of how selection has shaped phenotypes. Here, we estimated the (co)variances among three different behaviors (activity, aggression, and anti-predator response) in a natural population of deer mice (Peromyscus maniculatus). Using multi-response generalized mixed effects models, we divided the phenotypic covariance matrix into among- and within-individual matrices. The among-individual covariances includes genetic and permanent environmental covariances (e.g. developmental plasticity) and is predicted to align with selection. Simultaneously, we estimated the within-individual (co)variances, which include reversible phenotypic plasticity. To determine whether genetic variation, plasticity and selection align in multivariate space we calculated the dimensions containing the greatest among-individual variation and the dimension in which most plasticity was expressed (i.e. the dominant eigenvector for the among- and within-individual covariance matrices respectively). We estimated selection coefficients based on survival estimates from a mark-recapture model. Alignment between the dominant eigenvectors of behavioural variation and the selection gradient was estimated by calculating the angle between them, with an angle of 0 indicating perfect alignment. The angle between vectors ranged from 68 to 89, indicating that genetic variation, phenotypic plasticity, and selection are misaligned in this population. This misalignment could be due to the behaviors being close to their fitness optima, which is supported by low evolvabilities, or because of low selection pressure on these behaviors.

1989 ◽  
Vol 264 (10) ◽  
pp. 5593-5597
Author(s):  
C Norsten ◽  
T Cronholm ◽  
G Ekström ◽  
J A Handler ◽  
R G Thurman ◽  
...  

Virology ◽  
1994 ◽  
Vol 204 (2) ◽  
pp. 563-568 ◽  
Author(s):  
Vivek R. Nerurkar ◽  
Jin-Won Song ◽  
Ki-Joon Song ◽  
James W. Nagle ◽  
Brian Hjelle ◽  
...  

1985 ◽  
Vol 58 (1) ◽  
pp. 193-199 ◽  
Author(s):  
L. R. Snyder

Whereas it is widely believed that animals native to high altitude show lower O2 partial pressures at 50% hemoglobin saturation (P50) than do related animals native to low altitude, that “fact” has not been well documented. Consequently, P50 at pH 7.4, PCO2(7.4), the CO2 Bohr effect, and the buffer slope (delta log PCO2/delta pH) were determined via the mixing technique in Peromyscus maniculatus native to a range of altitudes but acclimated to 340 or 3,800 m. PCO2(7.4) and buffer slope were substantially lower at high altitude. The change in P50(7.4) between acclimation altitudes was minimal (0.8% increase at 3,800 m), because of counterbalancing changes in PCO2, 2,3-diphospho-D-glycerate concentration, and perhaps other factors. At both acclimation altitudes there was a highly significant negative correlation between P50(7.4) and native altitude. Since pH in vivo probably increases slightly at high altitude, the data on P50 corrected to pH 7.4 are probably underestimates of the difference in in vivo P50 at low vs. high altitude. Hence these results corroborate theoretical predictions that low P50 is advantageous under severe hypoxic stress.


2018 ◽  
Author(s):  
Michelle F. DiLeo ◽  
Arild Husby ◽  
Marjo Saastamoinen

AbstractThere is now clear evidence that species across a broad range of taxa harbour extensive heritable variation in dispersal. While studies suggest that this variation can facilitate demographic outcomes such as range expansion and invasions, few have considered the consequences of intraspecific variation in dispersal for the maintenance and distribution of genetic variation across fragmented landscapes. Here we examine how landscape characteristics and individual variation in dispersal combine to predict genetic structure using genomic and spatial data from the Glanville fritillary butterfly. We used linear and latent factor mixed models to identify the landscape features that best predict spatial sorting of alleles in the dispersal-related gene phosphoglucose isomerase (Pgi). We next used structural equation modeling to test if variation in Pgi mediated gene flow as measured by Fst at putatively neutral loci. In a year when the population was expanding following a large decline, individuals with a genotype associated with greater dispersal ability were found at significantly higher frequencies in populations isolated by water and forest, and these populations showed lower levels of genetic differentiation at neutral loci. These relationships disappeared in the next year when metapopulation density was high, suggesting that the effects of individual variation are context dependent. Together our results highlight that 1) more complex aspects of landscape structure beyond just the configuration of habitat can be important for maintaining spatial variation in dispersal traits, and 2) that individual variation in dispersal plays a key role in maintaining genetic variation across fragmented landscapes.Impact summaryUnderstanding how fragmentation affects dispersal and gene flow across human-modified landscapes has long been a goal in evolutionary biology. It is typically assumed that individuals of the same species respond to the landscape in the same way, however growing evidence suggests that individuals can vary considerably in their dispersal traits. While the effects of this individual dispersal variation on range expansions and invasions have been well-characterized, knowledge of how it might mediate genetic responses to landscape fragmentation are almost entirely lacking. Here we demonstrate that individual variation in dispersal is key to the maintenance of genetic variation during a population expansion following a large decline in a butterfly metapopulation. We further show that spatial variation in dispersal is not maintained by the configuration of habitat patches alone, but by a more complex genotype-environment interaction involving the landscape matrix (i.e. landscape features found between habitat patches). This challenges the simplified landscape representations typically used in studies of dispersal evolution that ignore heterogeneity in the landscape matrix. More broadly, our results highlight the interplay of adaptive and neutral processes across fragmented landscapes, suggesting that an understanding of species vulnerability to landscape fragmentation requires consideration of both.


2021 ◽  
Author(s):  
Catherine M. Ivy ◽  
Oliver H. Wearing ◽  
Chandrasekhar Natarajan ◽  
Rena M. Schweizer ◽  
Natalia Gutiérrez-Pinto ◽  
...  

ABSTRACTPhysiological systems often have emergent properties but the effects of genetic variation on physiology are often unknown, which presents a major challenge to understanding the mechanisms of phenotypic evolution. We investigated the in vivo effects on respiratory physiology of genetic variants in haemoglobin (Hb) that contribute to hypoxia adaptation in high-altitude deer mice (Peromyscus maniculatus). We created F2 inter-population hybrids of highland and lowland deer mice to test the phenotypic effects of α- and β-globin variants on a mixed genetic background. High-altitude genotypes were associated with breathing phenotypes that enhance O2 uptake in hypoxia, including a deeper more effective breathing pattern and an augmented hypoxic ventilatory response. These effects could not be explained by erythrocyte Hb-O2 affinity or globin gene expression in the brainstem. Therefore, adaptive variation in haemoglobin can have unexpected effects on physiology that are distinct from the canonical function of this protein in circulatory O2 transport.


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