scholarly journals Large single-locus effects for maturation timing are mediated via body condition in Atlantic salmon

2019 ◽  
Author(s):  
Paul V Debes ◽  
Nikolai Piavchenko ◽  
Annukka Ruokolainen ◽  
Outi Ovaskainen ◽  
Jacqueline E Moustakas-Verho ◽  
...  
Keyword(s):  
Life History ◽  
Atlantic Salmon ◽  
Body Condition ◽  
Genetic Correlations ◽  
Common Garden ◽  
Life History Trait ◽  
Reverse Causality ◽  
Female Condition ◽  
Two Temperatures ◽  
Genetic Contributions

AbstractMaturation timing is a pivotal life-history trait balancing probabilities between mortality and reproduction. Environmental vs. genetic contributions to traits associated with maturation initiation, such as growth and body condition, remain uncertain because of difficulties in determining causality. In Atlantic salmon, maturation timing associates with a large-effect locus around vgll3, but how this locus affects maturation remains unknown. We combined controlled breeding with common-garden experimentation at two temperatures and show that vgll3 effects on maturation of males express primarily via body condition, which we demonstrate in the males’ non-maturing female relatives, thus avoiding reverse causality. Between homozygous vgll3 genotypes, maturation probability differed several folds and female condition differed 2% in both temperature environments. Vgll3 effects explained 25 and 16% of maturation probability heritability and 15 and 6% of female condition heritability, in the warm and cold environment, respectively. Non-significant vgll3 effects on female length were antagonistic to those on condition but of equal proportional size. When controlling for vgll3 effects, genetic correlations changed antagonistically between both maturation and condition vs. growth, suggesting vgll3 as a resource-allocation locus. The results support large vgll3 maturation effects being mediated via environmentally stable body condition effects, enabling rapid co-evolution between the life-history traits.

scholarly journals Genetic correlation between sea age at maturity and iteroparity in Atlantic salmon

2018 ◽  
Author(s):  
Tutku Aykanat ◽  
Mikhail Ozerov ◽  
Juha-Pekka Vähä ◽  
Panu Orell ◽  
Eero Niemelä ◽  
...  
Keyword(s):  
Life History ◽  
Atlantic Salmon ◽  
Genetic Correlations ◽  
Age Groups ◽  
Life History Trait ◽  
Age At Maturity ◽  
Life History Variation ◽  
Functional Link ◽  
Physiological Basis ◽  
Genome Region

AbstractGenetic correlations in life history traits may result in unpredictable evolutionary trajectories if not accounted for in life-history models. Iteroparity (the reproductive strategy of reproducing more than once) in Atlantic salmon (Salmo salar) is a fitness trait with substantial variation within and among populations. In the Teno River in northern Europe, iteroparous individuals constitute an important component of many populations and have experienced a sharp increase in abundance in the last 20 years, partly overlapping with a general decrease in age structure. The physiological basis of iteroparity bears similarities to that of age at first maturity, another life history trait with substantial fitness effects in salmon. Sea age at maturity in Atlantic salmon is controlled by a major locus around the vgll3 gene, and we used this opportunity demonstrate that the two traits are genetically correlated around this genome region. The odds ratio of survival until second reproduction was up to 2.4 (1.8-3.5 90% CI) times higher for fish with the early-maturing vgll3 genotype (EE) compared to fish with the late-maturing genotype (LL). The association had a dominance architecture, although the dominant allele was reversed in the late-maturing group compared to younger groups that stayed only one year at sea before maturation. Post hoc analysis indicated that iteroparous fish with the EE genotype had accelerated growth prior to first reproduction compared to first-time spawners, across all age groups, while this effect was not detected in fish with the LL genotype. These results broaden the functional link around the vgll3 genome region and help us understand constraints in the evolution of life history variation in salmon. Our results further highlight the need to account for genetic correlations between fitness traits when predicting demographic changes in changing environments.

scholarly journals Sex-specific lipid profiles in muscle of Atlantic salmon juveniles

2020 ◽  
Author(s):  
Andrew H. House ◽  
Paul V. Debes ◽  
Johanna Kurko ◽  
Jaakko Erkinaro ◽  
Reijo Käkelä ◽  
...  
Keyword(s):  
Life History ◽  
Atlantic Salmon ◽  
Juvenile Fish ◽  
Common Garden ◽  
Energy Allocation ◽  
Relative Energy ◽  
Life History Trait ◽  
Major Life ◽  
Muscle Lipid ◽  
Juvenile Development

AbstractEnergy allocation in juvenile fish can have important implications for future life-history progression. Inherited and environmental factors determine when and where individuals allocate energy, and timely and sufficient energy reserves are crucial for reaching key life stages involved in the timing of maturation and sea migration. In Atlantic salmon, lipid reserves are predominantly found in the viscera and myosepta in the muscle and have been shown to play a key role in determining the timing of maturity. This life-history trait is tightly linked to fitness in many species and can be different between males and females, however, the details of relative energy allocation in juveniles of different sexes is not well understood. Therefore, the aim of this study was to investigate the effects of sex, genetics and environment during juvenile development of salmon on the amount and composition of their lipid reserves. To do so, juvenile salmon were fed one of two different lipid food contents during their first summer and autumn under common-garden conditions. Muscle lipid composition and concentrations were determined by thin layer chromatography. The muscle lipid class concentrations covaried negatively with body length and males showed higher concentrations than females for phosphatidylcholine, sphingomyelin, cholesterol and triacylglycerol. This sex-specific difference in major lipid classes presents a new scope for understanding the regulation of lipids during juvenile development and gives direction for understand how lipids may interact and influence major life-history traits in Atlantic salmon.

scholarly journals Mapping the adaptive landscape of a major agricultural pathogen reveals evolutionary constraints across heterogeneous environments

2021 ◽  
Author(s):  
Anik Dutta ◽  
Fanny E. Hartmann ◽  
Carolina Sardinha Francisco ◽  
Bruce A. McDonald ◽  
Daniel Croll
Keyword(s):  
Life History ◽  
Large Scale ◽  
Life History Traits ◽  
Genetic Correlations ◽  
Stress Factors ◽  
Life History Trait ◽  
Adaptive Landscape ◽  
Heterogeneous Environments ◽  
Growth Responses ◽  
Trade Offs

AbstractThe adaptive potential of pathogens in novel or heterogeneous environments underpins the risk of disease epidemics. Antagonistic pleiotropy or differential resource allocation among life-history traits can constrain pathogen adaptation. However, we lack understanding of how the genetic architecture of individual traits can generate trade-offs. Here, we report a large-scale study based on 145 global strains of the fungal wheat pathogen Zymoseptoria tritici from four continents. We measured 50 life-history traits, including virulence and reproduction on 12 different wheat hosts and growth responses to several abiotic stressors. To elucidate the genetic basis of adaptation, we used genome-wide association mapping coupled with genetic correlation analyses. We show that most traits are governed by polygenic architectures and are highly heritable suggesting that adaptation proceeds mainly through allele frequency shifts at many loci. We identified negative genetic correlations among traits related to host colonization and survival in stressful environments. Such genetic constraints indicate that pleiotropic effects could limit the pathogen’s ability to cause host damage. In contrast, adaptation to abiotic stress factors was likely facilitated by synergistic pleiotropy. Our study illustrates how comprehensive mapping of life-history trait architectures across diverse environments allows to predict evolutionary trajectories of pathogens confronted with environmental perturbations.

scholarly journals Life history evolution and phenotypic plasticity in parasitic eyebrights (Euphrasia, Orobanchaceae)

2018 ◽  
Author(s):  
Alex D. Twyford ◽  
Natacha Frachon ◽  
Edgar L. Y. Wong ◽  
Chris Metherell ◽  
Max R. Brown
Keyword(s):  
Life History ◽  
Phenotypic Plasticity ◽  
Reproductive Success ◽  
Life History Traits ◽  
Common Garden ◽  
Parasitic Plant ◽  
Life History Strategies ◽  
Life History Trait ◽  
Lifetime Reproductive Success ◽  
Host Quality

ABSTRACTPremise of the studyParasite lifetime reproductive success is determined by both genetic variation and phenotypically plastic life history traits that respond to host quality and external environment. Here, we use the generalist parasitic plant genus Euphrasia to investigate life history trait variation, in particular whether there is a trade-off between growth and reproduction, and how life history traits are affected by host quality.MethodsWe perform a common garden experiment to evaluate life history trait differences between eleven Euphrasia taxa grown on a common host, document phenotypic plasticity when a single Euphrasia species is grown on eight different hosts, and relate our observations to trait differences recorded in the wild.Key resultsEuphrasia exhibit a range of life history strategies that differ between species that transition rapidly to flower at the expense of early season growth, and those that invest in vegetative growth and delay flowering. Many life history traits show extensive phenotypic plasticity in response to host quality and demonstrate the costs of attaching to a low-quality host.ConclusionsCommon garden experiments reveal trait differences between taxonomically complex Euphrasia species that are characterised by postglacial speciation and hybridisation. Our experiments suggest life history strategies in this generalist parasitic plant genus are the product of natural selection on traits related to growth and flowering. However, host quality may be a primary determinant of lifetime reproductive success.

scholarly journals Genetic growth potential, rather than phenotypic size, predicts migration phenotype in Atlantic salmon

2020 ◽  
Vol 287 (1931) ◽  
pp. 20200867 ◽  
Author(s):  
Paul V. Debes ◽  
Nikolai Piavchenko ◽  
Jaakko Erkinaro ◽  
Craig R. Primmer
Keyword(s):  
Atlantic Salmon ◽  
Genetic Correlations ◽  
Late Summer ◽  
Growth Potential ◽  
Developmental Transitions ◽  
Feed Resources ◽  
Warm Environment ◽  
Feeding Regimes ◽  
Two Temperatures ◽  
Highly Correlated

Knowledge of the relative importance of genetic versus environmental determinants of major developmental transitions is pertinent to understanding phenotypic evolution. In salmonid fishes, a major developmental transition enables a risky seaward migration that provides access to feed resources. In Atlantic salmon, initiation of the migrant phenotype, and thus age of migrants, is presumably controlled via thresholds of a quantitative liability, approximated by body size expressed long before the migration. However, how well size approximates liability, both genetically and environmentally, remains uncertain. We studied 32 Atlantic salmon families in two temperatures and feeding regimes (fully fed, temporarily restricted) to completion of migration status at age 1 year. We detected a lower migrant probability in the cold (0.42) than the warm environment (0.76), but no effects of male maturation status or feed restriction. By contrast, body length in late summer predicted migrant probability and its control reduced migrant probability heritability by 50–70%. Furthermore, migrant probability and length showed high heritabilities and between-environment genetic correlations, and were phenotypically highly correlated with stronger genetic than environmental contributions. Altogether, quantitative estimates for the genetic and environmental effects predicting the migrant phenotype indicate, for a given temperature, a larger importance of genetic than environmental size effects.

scholarly journals Estimating the evolution of human life history traits in age-structured populations

2014 ◽  
Author(s):  
Ryan Baldini
Keyword(s):  
Life History ◽  
Human Life ◽  
Life History Evolution ◽  
Selection Response ◽  
Structured Populations ◽  
Life History Trait ◽  
Vital Rates ◽  
Structured Population ◽  
Age Structured ◽  
Genetic Contributions

I propose a method that estimates the selection response of all vital rates in an age-structured population. I assume that vital rates are determined by the additive genetic contributions of many loci. The method uses all relatedness information in the sample to inform its estimates of genetic parameters, via an MCMC Bayesian framework. One can use the results to estimate the selection response of any life history trait that is a function of the vital rates, including the age at first reproduction, total lifetime fertility, survival to adulthood, and others. This method closely ties the empirical analysis of life history evolution to dynamically complete models of natural selection, and therefore enjoys some theoretical advantages over other methods. I demonstrate the method on a simulated model of evolution with two age classes. Finally I discuss how the method can be extended to more complicated cases.

scholarly journals Heterogeneous genetic basis of age at maturity in salmonid fishes

2020 ◽  
Author(s):  
Charles D. Waters ◽  
Anthony Clemento ◽  
Tutku Aykanat ◽  
John Carlos Garza ◽  
Kerry A. Naish ◽  
...  
Keyword(s):  
Life History ◽  
Atlantic Salmon ◽  
Sockeye Salmon ◽  
Genetic Basis ◽  
Coho Salmon ◽  
Strong Association ◽  
Life History Trait ◽  
Age At Maturity ◽  
A Genome ◽  
Conservation And Management

AbstractUnderstanding the genetic basis of repeated evolution of the same phenotype across taxa is a fundamental aim in evolutionary biology and has applications to conservation and management. However, the extent to which interspecific life-history trait polymorphisms share evolutionary pathways remains under-explored. We address this gap by studying the genetic basis of a key life-history trait, age at maturity, in four species of Pacific salmon (genus Oncorhynchus) that exhibit intra- and interspecific variation in this trait – Chinook Salmon, Coho Salmon, Sockeye Salmon, and Steelhead Trout. We tested for associations in all four species between age at maturity and two genome regions, six6 and vgll3, that are strongly associated with the same trait in Atlantic Salmon (Salmo salar). We also conducted a genome-wide association analysis in Steelhead to assess whether additional regions were associated with this trait. We found the genetic basis of age at maturity to be heterogeneous across salmonid species. Significant associations between six6 and age at maturity were observed in two of the four species, Sockeye and Steelhead, with the association in Steelhead being particularly strong in both sexes (p = 4.46×10−9 after adjusting for genomic inflation). However, no significant associations were detected between age at maturity and the vgll3 genome region in any of the species, despite its strong association with the same trait in Atlantic Salmon. We discuss possible explanations for the heterogeneous nature of the genetic architecture of this key life-history trait, as well as the implications of our findings for conservation and management.

scholarly journals Cis-regulatory differences in isoform expression associate with life history strategy variation in Atlantic salmon

2019 ◽  
Author(s):  
Jukka-Pekka Verta ◽  
Paul Vincent Debes ◽  
Nikolai Piavchenko ◽  
Annukka Ruokolainen ◽  
Outi Ovaskainen ◽  
...  
Keyword(s):  
Life History ◽  
Atlantic Salmon ◽  
Life Histories ◽  
Life History Traits ◽  
Life History Strategies ◽  
Life History Trait ◽  
Gene Transcript ◽  
Genome Wide Association Studies ◽  
Age At Maturity ◽  
Life History Variation

AbstractA major goal in biology is to understand how evolution shapes variation in individual life histories. Genome-wide association studies have been successful in uncovering genome regions linked with traits underlying life history variation in a range of species. However, lack of functional studies of the discovered genotype-phenotype associations severely restrains our understanding how alternative life history traits evolved and are mediated at the molecular level. Here, we report a cis-regulatory mechanism whereby expression of alternative isoforms of the transcription co-factor vestigial-like 3 (vgll3) associate with variation in a key life history trait, age at maturity, in Atlantic salmon (Salmo salar). Using a common-garden experiment, we first show that vgll3 genotype associates with puberty timing in one-year-old salmon males. By way of temporal sampling of vgll3 expression in ten tissues across the first year of salmon development, we identify a pubertal transition in vgll3 expression where maturation coincided with a 66% reduction in testicular vgll3 expression. The late maturation allele was not only associated with a tendency to delay puberty, but also with expression of a rare transcript isoform of vgll3 pre-puberty. By comparing absolute vgll3 mRNA copies in heterozygotes we show that the expression difference between the early and late maturity alleles is largely cis-regulatory. We propose a model whereby expression of a rare isoform from the late allele shifts the liability of its carriers towards delaying puberty. These results reveal how regulatory differences can be a central mechanism for the evolution of life history traits.Author summaryAlternative life history strategies are an important source of diversity within populations and promote the maintenance of adaptive capacity and population resilience. However, in many cases the molecular basis of different life history strategies remains elusive. Age at maturity is a key adaptive life history trait in Atlantic salmon and has a relatively simple genetic basis. Using salmon age at maturity as a model, we report a mechanism whereby different transcript isoforms of the key age at maturity gene, vestigial-like 3 (vgll3), associate with variation in the timing of male puberty. Our results show how gene regulatory differences in conjunction with variation in gene transcript structure can encode for complex alternative life histories.

scholarly journals Natural variation in fecundity is correlated with species-wide levels of divergence in Caenorhabditis elegans

2021 ◽  
Author(s):  
Gaotian Zhang ◽  
Jake D Mostad ◽  
Erik C Andersen
Keyword(s):  
Life History ◽  
Caenorhabditis Elegans ◽  
Life History Traits ◽  
Life History Trait ◽  
Selective Sweeps ◽  
C Elegans ◽  
Genome Wide ◽  
Genetic Complexity ◽  
Genomic Regions ◽  
Global Population

Abstract Life history traits underlie the fitness of organisms and are under strong natural selection. A new mutation that positively impacts a life history trait will likely increase in frequency and become fixed in a population (e.g. a selective sweep). The identification of the beneficial alleles that underlie selective sweeps provides insights into the mechanisms that occurred during the evolution of a species. In the global population of Caenorhabditis elegans, we previously identified selective sweeps that have drastically reduced chromosomal-scale genetic diversity in the species. Here, we measured the fecundity of 121 wild C. elegans strains, including many recently isolated divergent strains from the Hawaiian islands and found that strains with larger swept genomic regions have significantly higher fecundity than strains without evidence of the recent selective sweeps. We used genome-wide association (GWA) mapping to identify three quantitative trait loci (QTL) underlying the fecundity variation. Additionally, we mapped previous fecundity data from wild C. elegans strains and C. elegans recombinant inbred advanced intercross lines that were grown in various conditions and detected eight QTL using GWA and linkage mappings. These QTL show the genetic complexity of fecundity across this species. Moreover, the haplotype structure in each GWA QTL region revealed correlations with recent selective sweeps in the C. elegans population. North American and European strains had significantly higher fecundity than most strains from Hawaii, a hypothesized origin of the C. elegans species, suggesting that beneficial alleles that caused increased fecundity could underlie the selective sweeps during the worldwide expansion of C. elegans.

Effect of time of day, time of year, and life history strategy on time budgeting in juvenile Atlantic salmon, Salmo salar

1999 ◽  
Vol 56 (12) ◽  
pp. 2397-2403 ◽  
Author(s):  
Sveinn K Valdimarsson ◽  
Neil B Metcalfe
Keyword(s):  
Life History ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Life History Strategy ◽  
Time Of Day ◽  
Life History Strategies ◽  
Foraging Efficiency ◽  
Atlantic Salmon Salmo Salar ◽  
Juvenile Atlantic Salmon ◽  
Time Of Year

Traditionally, behavioural studies on juvenile Atlantic salmon, Salmo salar, have been conducted during the day in summer. It is known that Atlantic salmon become nocturnal in winter, but very little is known about their behaviour at that time. Therefore, observations in a seminatural stream were carried out during the day and night, from February to June, comparing diel and seasonal differences in behaviour between fish adopting alternative life history strategies. The results showed a general trend for more activity in spring than in winter, and the fish were found to be foraging at surprisingly low light levels. There were differences in relative feeding rate between the life history strategies; the early migrant fish foraged mostly during the day whereas the delayed migrant fish did more foraging at night. There is some evidence that the early migrant fish made fewer feeding attempts over the winter, which is surprising, since they grow faster over that period. This suggests differences in foraging efficiency, which could contribute to the separation into these two life history strategies.

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