Skip header and navigation

6 records – page 1 of 1.

Differences among families in craniofacial shape at early life-stages of Arctic charr (Salvelinus alpinus).

https://arctichealth.org/en/permalink/ahliterature304365
Source
BMC Dev Biol. 2020 10 26; 20(1):21
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
10-26-2020
Author
Samantha V Beck
Katja Räsänen
Camille A Leblanc
Skúli Skúlason
Zophonías O Jónsson
Bjarni K Kristjánsson
Author Affiliation
Department of Aquaculture and Fish Biology, Hólar University, 551, Sauðárkrókur, Iceland. beck@holar.is.
Source
BMC Dev Biol. 2020 10 26; 20(1):21
Date
10-26-2020
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Abstract
Organismal fitness can be determined at early life-stages, but phenotypic variation at early life-stages is rarely considered in studies on evolutionary diversification. The trophic apparatus has been shown to contribute to sympatric resource-mediated divergence in several taxa. However, processes underlying diversification in trophic traits are poorly understood. Using phenotypically variable Icelandic Arctic charr (Salvelinus alpinus), we reared offspring from multiple families under standardized laboratory conditions and tested to what extent family (i.e. direct genetic and maternal effects) contributes to offspring morphology at hatching (H) and first feeding (FF). To understand the underlying mechanisms behind early life-stage variation in morphology, we examined how craniofacial shape varied according to family, offspring size, egg size and candidate gene expression.
Craniofacial shape (i.e. the Meckel's cartilage and hyoid arch) was more variable between families than within families both across and within developmental stages. Differences in craniofacial morphology between developmental stages correlated with offspring size, whilst within developmental stages only shape at FF correlated with offspring size, as well as female mean egg size. Larger offspring and offspring from females with larger eggs consistently had a wider hyoid arch and contracted Meckel's cartilage in comparison to smaller offspring.
This study provides evidence for family-level variation in early life-stage trophic morphology, indicating the potential for parental effects to facilitate resource polymorphism.
PubMed ID
33106153 View in PubMed
Less detail

Gene expression in the phenotypically plastic Arctic charr (Salvelinus alpinus): A focus on growth and ossification at early stages of development.

https://arctichealth.org/en/permalink/ahliterature296155
Source
Evol Dev. 2018 Nov 26; :
Publication Type
Journal Article
Date
Nov-26-2018
Author
Samantha V Beck
Katja Räsänen
Ehsan P Ahi
Bjarni K Kristjánsson
Skúli Skúlason
Zophonías O Jónsson
Camille A Leblanc
Author Affiliation
Department of Aquaculture and Fish Biology, Hólar University College, Háskólinn á Hólum, Sauðárkrókur, Iceland.
Source
Evol Dev. 2018 Nov 26; :
Date
Nov-26-2018
Language
English
Publication Type
Journal Article
Abstract
Gene expression during development shapes the phenotypes of individuals. Although embryonic gene expression can have lasting effects on developmental trajectories, few studies consider the role of maternal effects, such as egg size, on gene expression. Using qPCR, we characterize relative expression of 14 growth and/or skeletal promoting genes across embryonic development in Arctic charr (Salvelinus alpinus). We test to what extent their relative expression is correlated with egg size and size at early life-stages within the study population. We predict smaller individuals to have higher expression of growth and skeletal promoting genes, due to less maternal resources (i.e., yolk) and prioritization of energy toward ossification. We found expression levels to vary across developmental stages and only three genes (Mmp9, Star, and Sgk1) correlated with individual size at a given developmental stage. Contrary to our hypothesis, expression of Mmp9 and Star showed a non-linear relationship with size (at post fertilization and hatching, respectively), whilst Sgk1 was higher in larger embryos at hatching. Interestingly, these genes are also associated with craniofacial divergence of Arctic charr morphs. Our results indicate that early life-stage variation in gene expression, concomitant to maternal effects, can influence developmental plasticity and potentially the evolution of resource polymorphism in fishes.
PubMed ID
30474913 View in PubMed
Less detail

Genetic architecture of body weight, condition factor and age of sexual maturation in Icelandic Arctic charr (Salvelinus alpinus).

https://arctichealth.org/en/permalink/ahliterature100997
Source
Mol Genet Genomics. 2011 May 28;
Publication Type
Article
Date
May-28-2011
Author
Eva Küttner
Hooman K Moghadam
Skúli Skúlason
Roy G Danzmann
Moira M Ferguson
Author Affiliation
Department of Integrative Biology, University of Guelph, 50 Stone Road West, Guelph, ON, N1G 2W1, Canada.
Source
Mol Genet Genomics. 2011 May 28;
Date
May-28-2011
Language
English
Publication Type
Article
Abstract
The high commercial value from the aquaculture of salmonid fishes has prompted many studies into the genetic architecture of complex traits and the need to identify genomic regions that have repeatable associations with trait variation both within and among species. We searched for quantitative trait loci (QTL) for body weight (BW), condition factor (CF) and age of sexual maturation (MAT) in families of Arctic charr (Salvelinus alpinus) from an Icelandic breeding program. QTL with genome-wide significance were detected for each trait on multiple Arctic charr (AC) linkage groups (BW: AC-4, AC-20; CF: AC-7, AC-20, AC-23, AC-36; MAT: AC-13/34, AC-39). In addition to the genome-wide significant QTL for both BW and CF on AC-20, linkage groups AC-4, AC-7, AC-8, and AC-16 contain QTL for both BW and CF with chromosome-wide significance. These regions had effects (albeit weaker) on MAT with the exception of the region on AC-8. Comparisons with a North American cultured strain of Arctic charr, as well as North American populations of Atlantic salmon (Salmo salar), and rainbow trout (Oncorhynchus mykiss), reveal some conservation in QTL location and structure, particularly with respect to the joint associations of QTL influencing BW and CF. The detection of some differences in genetic architecture between the two aquaculture strains of Arctic charr may be reflective of the differential evolutionary histories experienced by these fishes, and illustrates the importance of including different strains to investigate genetic variation in a species where the intent is to use that variation in selective breeding programs.
PubMed ID
21626198 View in PubMed
Less detail

Hidden genetic variation evolves with ecological specialization: the genetic basis of phenotypic plasticity in Arctic charr ecomorphs.

https://arctichealth.org/en/permalink/ahliterature259330
Source
Evol Dev. 2014 Jul-Aug;16(4):247-57
Publication Type
Article
Author
Eva Küttner
Kevin J Parsons
Anne A Easton
Skuli Skúlason
Roy G Danzmann
Moira M Ferguson
Source
Evol Dev. 2014 Jul-Aug;16(4):247-57
Language
English
Publication Type
Article
Keywords
Animals
Body Size
Female
Gene-Environment Interaction
Genetic Variation
Male
Quantitative Trait Loci
Skull - anatomy & histology
Trout - anatomy & histology - genetics
Abstract
The genetic variance that determines phenotypic variation can change across environments through developmental plasticity and in turn play a strong role in evolution. Induced changes in genotype-phenotype relationships should strongly influence adaptation by exposing different sets of heritable variation to selection under some conditions, while also hiding variation. Therefore, the heritable variation exposed or hidden from selection is likely to differ among habitats. We used ecomorphs from two divergent populations of Arctic charr (Salvelinus alpinus) to test the prediction that genotype-phenotype relationships would change in relation to environment. If present over several generations this should lead to divergence in genotype-phenotype relationships under common conditions, and to changes in the amount and type of hidden genetic variance that can evolve. We performed a common garden experiment whereby two ecomorphs from each of two Icelandic lakes were reared under conditions that mimicked benthic and limnetic prey to induce responses in craniofacial traits. Using microsatellite based genetic maps, we subsequently detected QTL related to these craniofacial traits. We found substantial changes in the number and type of QTL between diet treatments and evidence that novel diet treatments can in some cases provide a higher number of QTL. These findings suggest that selection on phenotypic variation, which is both genetically and environmentally determined, has shaped the genetic architecture of adaptive divergence in Arctic charr. However, while adaptive changes are occurring in the genome there also appears to be an accumulation of hidden genetic variation for loci not expressed in the contemporary environment.
PubMed ID
24920458 View in PubMed
Less detail

Morphological variation over ontogeny and environments in resource polymorphic arctic charr (Salvelinus alpinus).

https://arctichealth.org/en/permalink/ahliterature96626
Source
Evol Dev. 2010 May;12(3):246-57
Publication Type
Article
Date
May-2010
Author
Kevin J Parsons
Skuli Skúlason
Moira Ferguson
Author Affiliation
Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada. kjpars01@syr.edu
Source
Evol Dev. 2010 May;12(3):246-57
Date
May-2010
Language
English
Publication Type
Article
Abstract
Natural selection requires genetically based phenotypic variation to facilitate its action and cause adaptive evolution. It has become increasingly recognized that morphological development can become canalized likely as a result of selection. However, it is largely unknown how selection may influence canalization over ontogeny and differing environments. Changes in environments or colonization of a novel one is expected to result in adaptive divergence from the ancestral population when selection favors a new phenotypic optimum. In turn, a novel environment may also expose variation previously hidden from natural selection. We tested for changes in phenotypic variation over ontogeny and environments among ecomorphs of Arctic charr (Salvelinus alpinus) from two Icelandic lakes. Populations represented varying degrees of ecological specialization, with one lake population possessing highly specialized ecomorphs exhibiting a large degree of phenotypic divergence, whereas the other displayed more subtle divergence with more ecological overlap. Here we show that ecomorphs hypothesized to be the most specialized in each lake possess significant reductions in shape variation over ontogeny regardless of environmental treatment suggesting canalized development. However, environments did change the amount of shape variation expressed in these ecomorphs, with novel environments slowing the rate at which variation was reduced over ontogeny. Thus, environmental conditions may play an important role in determining the type and amount of genetically based phenotypic variation exposed to natural selection.
PubMed ID
20565535 View in PubMed
Less detail

Natural selection for body shape in resource polymorphic Icelandic Arctic charr.

https://arctichealth.org/en/permalink/ahliterature292669
Source
J Evol Biol. 2018 Jul 01; :
Publication Type
Journal Article
Date
Jul-01-2018
Author
Oliver D Franklin
Skúli Skúlason
Michael B Morrissey
Moira M Ferguson
Author Affiliation
Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
Source
J Evol Biol. 2018 Jul 01; :
Date
Jul-01-2018
Language
English
Publication Type
Journal Article
Abstract
Resource polymorphisms exhibit remarkable intraspecific diversity and in many cases are expected to be maintained by diversifying selection. Phenotypic trade-offs can constrain morphologically intermediate individuals from effectively exploiting both alternate resources, resulting in ecological barriers to gene flow. Determining if and how phenotypic trade-offs cause fitness variation in the wild is challenging because of phenotypic and environmental correlations associated with alternative resource strategies. We investigated multiple pathways through which morphology could affect organismal performance, as measured by growth rate, and whether these effects generate diversifying selection in polymorphic Icelandic Arctic charr (Salvelinus alpinus) populations. We considered direct effects of morphology on growth and indirect effects via trophic resource use, estimated by stable isotopic signatures, and via parasitism associated with trophic resources. We sampled over three years in (lakes) Thingvallavatn and Vatnshlíðarvatn using the extended selection gradient path analytical approach and estimating size-dependent mortality. We found evidence for diversifying selection only in Thingvallavatn: more streamlined and terminally-mouthed planktivore charr experienced greater growth, with the opposite pattern in small benthic charr. However, this effect was mediated by parasitism and non-trophic pathways, rather than trophic performance as often expected. Detection of between-morph differences in the presence (Vatnshlíðarvatn) and direction (Thingvallavatn) of size-dependent mortality, together with non-trophic effects of shape, suggest that a morphological trophic performance explanation for polymorphism is insufficient. This rare insight into selection during early diversification suggests that a complex of interacting local factors must be considered to understand how phenotype influences fitness, despite morphological variation reflecting intuitive trade-off explanations. This article is protected by copyright. All rights reserved.
PubMed ID
29961959 View in PubMed
Less detail

6 records – page 1 of 1.