scholarly journals Rapid sex-specific evolution of age at maturity is shaped by genetic architecture in Atlantic salmon

2018 ◽  
Author(s):  
Y. Czorlich ◽  
T. Aykanat ◽  
J. Erkinaro ◽  
P. Orell ◽  
CR. Primmer

AbstractUnderstanding the mechanisms by which populations adapt to their environments is a fundamental aim in biology. However, it remains challenging to identify the genetic basis of traits, provide evidence of genetic changes and quantify phenotypic responses. Age at maturity in Atlantic salmon represents an ideal trait to study contemporary adaptive evolution as it has been associated with a single locus in the vgll3 region, and has also strongly changed in recent decades. Here, we provide an empirical example of contemporary adaptive evolution of a large effect locus driving contrasting sex-specific evolutionary responses at the phenotypic level. We identified an 18% decrease in the vgll3 allele associated with late maturity (L) in a large and diverse salmon population over 36 years, induced by sex-specific selection during the sea migration. Those genetic changes resulted in a significant evolutionary response in males only, due to sex-specific dominance patterns and vgll3 allelic effects. The vgll3 allelic and dominance effects differed greatly in a second population and were likely to generate different selection and evolutionary patterns. Our study highlights the importance of knowledge of genetic architecture to better understand fitness trait evolution and phenotypic diversity. It also emphasizes the potential role of adaptive evolution in the trend toward earlier maturation observed in numerous Atlantic salmon populations worldwide.

2017 ◽  
Vol 372 (1712) ◽  
pp. 20160035 ◽  
Author(s):  
Anna Kuparinen ◽  
Jeffrey A. Hutchings

Life-history traits are generally assumed to be inherited quantitatively. Fishing that targets large, old individuals is expected to decrease age at maturity. In Atlantic salmon ( Salmo salar ), it has recently been discovered that sea age at maturity is under strong control by a single locus with sexually dimorphic expression of heterozygotes, which makes it less intuitive to predict how life histories respond to selective fishing. We explore evolutionary responses to fishing in Atlantic salmon, using eco-evolutionary simulations with two alternative scenarios for the genetic architecture of age at maturity: (i) control by multiple loci with additive effects and (ii) control by one locus with sexually dimorphic expression. We show that multi-locus control leads to unidirectional evolution towards earlier maturation, whereas single-locus control causes largely divergent and disruptive evolution of age at maturity without a clear phenotypic trend but a wide range of alternative evolutionary trajectories and greater trait variability within trajectories. Our results indicate that the range of evolutionary responses to selective fishing can be wider than previously thought and that a lack of phenotypic trend need not imply that evolution has not occurred. These findings underscore the role of genetic architecture of life-history traits in understanding how human-induced selection can shape target populations. This article is part of the themed issue ‘Human influences on evolution, and the ecological and societal consequences’.


2006 ◽  
Vol 63 (7) ◽  
pp. 1286-1289 ◽  
Author(s):  
Fernando Ayllon ◽  
Jose L. Martinez ◽  
Francis Juanes ◽  
Stephen Gephard ◽  
Eva Garcia-Vazquez

Abstract The Connecticut River lost its Atlantic salmon population as a result of human activity 200 years ago. Cultured stocks, derived mainly from the Penobscot River, were employed to restore the population, and an annual run of salmon has been successfully re-established, although the population is not yet self-sustaining. We examined variation at microsatellite loci in historical scale and modern tissue samples to evaluate the degree and direction of any genetic changes that have occurred in the introduced population. The current genetic pattern of the Connecticut River population is very similar to that of its Penobscot River donor population. We found no differences in heterozygosity, mean number of alleles per locus, number of migrants, or FST values between the two populations, suggesting that no genetic bottlenecks had occurred during the restoration programme.


2018 ◽  
Vol 2 (11) ◽  
pp. 1800-1807 ◽  
Author(s):  
Yann Czorlich ◽  
Tutku Aykanat ◽  
Jaakko Erkinaro ◽  
Panu Orell ◽  
Craig Robert Primmer

PLoS ONE ◽  
2015 ◽  
Vol 10 (7) ◽  
pp. e0132980
Author(s):  
Ulrike Ober ◽  
Wen Huang ◽  
Michael Magwire ◽  
Martin Schlather ◽  
Henner Simianer ◽  
...  

2017 ◽  
Vol 33 (7) ◽  
pp. 1004-1015 ◽  
Author(s):  
G. A. Maynard ◽  
M. T. Kinnison ◽  
J. D. Zydlewski

1986 ◽  
Vol 43 (6) ◽  
pp. 1242-1248 ◽  
Author(s):  
Ransom A. Myers ◽  
Jeffrey A. Hutchings ◽  
R. John Gibson

The covariation of growth and maturation in male Atlantic salmon parr, Salmo salar, produces a relationship characterized by a size threshold below which individuals generally do not mature. The threshold of 70–72 mm fork length is evident both within and among populations. Parr maturation can reduce growth during the second year of life by an average of 4.0%. Among-year variation in growth rate affects the yearly incidence of maturation for males at age 1 + but has no detectable effect on the total proportion of male parr maturing in a population. Increases in the proportion of mature parr in the Matamek River, Quebec, can be explained by variation in growth alone; there is no evidence for genetic changes in this population.


2015 ◽  
Author(s):  
Fernando Ayllon ◽  
Erik Kjærner-Semb ◽  
Tomasz Furmanek ◽  
Vidar Wennevik ◽  
Monica F Solberg ◽  
...  

Wild and domesticated Atlantic salmon males display large variation for sea age at sexual maturation, which varies between 1-5 years. Previous studies have uncovered a genetic predisposition for age at maturity with moderate heritability, thus suggesting a polygenic or complex nature of this trait. The aim of this study was to identify associated genetic loci, genes and ultimately specific sequence variants conferring sea age at maturity in salmon. We performed a GWAS using a pool sequencing approach (20 individuals per river and trait) of salmon returning to rivers as sexually mature either after one sea winter (2009) or three sea winters (2011) in six rivers in Norway. The study revealed one major selective sweep, which covered 76 significant SNP in which 74 were found in a 370 kb region of chromosome 25. Genotyping other smolt year classes of wild salmon and domesticated salmon confirmed this finding. Genotyping domesticated fish narrowed the haplotype region to four SNPs covering 2386 bp, containing thevgll3gene, including two missense mutations explaining 33-36% phenotypic variation. This study demonstrates a single locus playing a highly significant role in governing sea age at maturation in this species. The SNPs identified may be both used as markers to guide breeding for late maturity in salmon aquaculture and in monitoring programs of wild salmon. Interestingly, a SNP in proximity of the VGLL3 gene in human (Homo sapiens), has previously been linked to age at puberty suggesting a conserved mechanism for timing of puberty in vertebrates.


2021 ◽  
Author(s):  
Yihan Wu ◽  
Robert I Colautti

The extent to which evolution can rescue a species from extinction, or facilitate range expansion, depends critically on the rate, duration, and geographical extent of the evolutionary response to natural selection. While field experiments have demonstrated that adaptive evolution can occur quickly, our understanding of the duration and geographical extent of contemporary evolution in natural systems remains limited. This is particularly true for species with large geographical ranges and for timescales that lie between 'long-term' field experiments and the fossil record. Here, we introduce the Virtual Common Garden (VCG) to estimate genetic differences among phenotypes observed in natural history collections. Reconstructing 150 years of evolution in Lythrum salicaria (purple loosestrife) as it invaded across North America, we analyze phenology measurements of 3,429 herbarium records, reconstruct growing conditions from more than 12 million local temperature records, and validate predictions across three common gardens spanning 10 degrees of latitude. We find that phenology evolves rapidly and repeatedly along parallel climatic gradients during the first century of evolution. However, the rate of microevolution stalls thereafter, recapitulating macroevolutionary stasis observed in the fossil record. Our study demonstrates why preserved specimens are a critical resource for understanding limits to evolution in natural. Our results show predictability of evolution emerging at a continental scale across 15 decades of rapid, adaptive evolution.


2018 ◽  
Vol 14 (5) ◽  
pp. 20180064 ◽  
Author(s):  
Lars Schmitz ◽  
Timothy E. Higham

Geckos feature a large range of eye sizes, but what drives this phenotypic diversity is currently unknown. Earlier studies point towards diel activity patterns (DAPs) and locomotory mode, but phylogenetic comparative studies in support of the proposed adaptive mode of eye evolution are lacking. Here, we test the hypothesis of DAPs as the driver of eye size evolution with a dataset on 99 species of gecko. Results from phylogenetic generalized least-square analysis (PGLS) and multivariate model-fitting reveal smaller eyes in diurnal geckos consistent with different phenotypic optima. However, Bayesian analyses of selective regime shifts demonstrate that only two of nine transitions from nocturnal to diurnal activity are coupled with decreases in eye size, and two other regime shifts are not associated with DAP transitions. This non-uniform evolutionary response suggests that eye size is not the only functionally relevant variable. Evolutionary adaptations may therefore include different combinations of several traits (e.g. photoreceptors), all with the same functional outcome. Our results further demonstrate that DAP only partially explains eye size diversity in geckos. As open habitats favour the evolution of large eyes while obstructed habitats favour small eyes, the degree of habitat clutter emerges as another potential axis of eye diversification.


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