Blar i NTNU Open på forfatter "Kvalnes, Thomas"
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Artificial size selection experiment reveals telomere length dynamics and fitness consequences in a wild passerine
Pepke, Michael Le; Kvalnes, Thomas; Rønning, Bernt; Jensen, Henrik; Boner, Winnie; Sæther, Bernt-Erik; Monaghan, Pat; Ringsby, Thor Harald (Peer reviewed; Journal article, 2022)Telomere dynamics could underlie life-history trade-offs among growth, size and longevity, but our ability to quantify such processes in natural, unmanipulated populations is limited. We investigated how 4 years of artificial ... -
Causes and consequences of variation in early-life telomere length in a bird metapopulation
Pepke, Michael Le; Kvalnes, Thomas; Ranke, Peter Sjolte; Araya-Ajoy, Yimen; Wright, Jonathan; Sæther, Bernt-Erik; Jensen, Henrik; Ringsby, Thor Harald (Peer reviewed; Journal article, 2022)Environmental conditions during early-life development can have lasting effects shaping individual heterogeneity in fitness and fitness-related traits. The length of telomeres, the DNA sequences protecting chromosome ends, ... -
Characterizing morphological (co)variation using structural equation models: Body size, allometric relationships and evolvability in a house sparrow metapopulation
Araya-Ajoy, Yimen; Ranke, Peter Sjolte; Kvalnes, Thomas; Rønning, Bernt; Holand, Håkon; Myhre, Ane Marlene; Pärn, Henrik; Jensen, Henrik; Ringsby, Thor Harald; Sæther, Bernt-Erik; Wright, Jonathan (Peer reviewed; Journal article, 2019)Body size plays a key role in the ecology and evolution of all organisms. Therefore, quantifying the sources of morphological (co)variation, dependent and independent of body size, is of key importance when trying to ... -
Controlling for P-value inflation in allele frequency change in experimental evolution and artificial selection experiments
Kemppainen, Petri; Rønning, Bernt; Kvalnes, Thomas; Hagen, Ingerid Julie; Ringsby, Thor Harald; Billing, Anna Maria; Pärn, Henrik; Lien, Sigbjørn; Husby, Arild; Sæther, Bernt-Erik; Jensen, Henrik (Journal article; Peer reviewed, 2017)Experimental evolution studies can be used to explore genomic response to artificial and natural selection. In such studies, loci that display larger allele frequency change than expected by genetic drift alone are assumed ... -
Demographic influences of translocated individuals on a resident population of house sparrows
Ranke, Peter Sjolte; Skjelseth, Sigrun; Pärn, Henrik; Herfindal, Ivar; Borg Pedersen, Åsa Alexandra; Stokke, Bård Gunnar; Kvalnes, Thomas; Ringsby, Thor Harald; Sæther, Bernt-Erik; Jensen, Henrik (Journal article; Peer reviewed, 2017)Translocation of individuals from source populations to augment small populations facing risk of extinction is an important conservation tool. Here we examine sex-specific differences between resident and translocated house ... -
Density-dependent selection and the maintenance of colour polymorphism in barn owls
Kvalnes, Thomas; Sæther, Bernt-Erik; Engen, Steinar; Roulin, Alexandre (Peer reviewed; Journal article, 2022)The capacity of natural selection to generate adaptive changes is (according to the fundamental theorem of natural selection) proportional to the additive genetic variance in fitness. In spite of its importance for development ... -
Dispersal in a house sparrow metapopulation: An integrative case study of genetic assignment calibrated with ecological data and pedigree information
Saatoglu, Fikriye Dilan; Niskanen, Alina Katariina; Kuismin, Markku; Ranke, Peter Sjolte; Hagen, Ingerid Julie; Araya-Ajoy, Yimen; Kvalnes, Thomas; Pärn, Henrik; Rønning, Bernt; Ringsby, Thor Harald; Sæther, Bernt-Erik; Husby, Arild; Sillanpää, Mikko J.; Jensen, Henrik (Peer reviewed; Journal article, 2021)Dispersal has a crucial role determining ecoevolutionary dynamics through both gene flow and population size regulation. However, to study dispersal and its consequences, one must distinguish immigrants from residents. ... -
The ecological and evolutionary role of telomere length in house sparrows
Pepke, Michael Le (Doctoral theses at NTNU;2021:420, Doctoral thesis, 2021)Telomeres, the DNA sequences capping the ends of linear chromosomes, are ancient molecular structures that are shared among most eucaryotes. The telomeres protect chromosomes from degradation and are vital to genome ... -
“Effect of inbreeding on egg size and clutch size in an insular house sparrow metapopulation in northern Norway”
Gholami, Fatemeh (Master thesis, 2023)Innavlsdepresjon er en av de største truslene mot overlevelsen til små, isolerte bestander. For å få en fullstendig forståelse av innavlens innvirkning på populasjonens levedyktighet er det nødvendig å kvantifisere ... -
Effects of inbreeding on lay date in house sparrows (Passer domesticus)
Muller, Amandine Sophie (Master thesis, 2021)Innavlsdepresjon (en reduksjon i individuell fitness forårsaket av innavl) har blitt observert hos mange ulike arter, men mekanismene som gir innavlsdepresjon er fremdeles uklare. Innavl og innavlsdepresjon studeres vanligvis ... -
Effects of Variation in Egg Size on Maternal Fitness in a Population of House Sparrows (Passer domesticus)
Krogfjord, Mari (Master thesis, 2018)According to life history theory individuals will optimize investment into growth, reproduction and self-maintenance. Egg size is an important life history trait predicted to have an optimum that maximizes maternal individual ... -
Effects of Variation in Egg Size on Offspring Fitness in Populations of House Sparrow (Passer domesticus)
Røberg, Anja Ås (Master thesis, 2015)1. Egg size represents an important life-history trait, which may have effects on the fitness of offspring. The effect of variation in egg size on offspring fitness has been studied within many taxa, but there is still a ... -
Evolution by natural selection in age-structured populations in fluctuating environments
Kvalnes, Thomas (Doctoral thesis at NTNU;2016:27, Doctoral thesis, 2016)Summary of thesis: In age-structured populations, subject to environmental and demographic stochasticity, the response to selection on fitness-related traits will be a complex result of selection at different life stages. ... -
Fur colour in the Arctic fox: genetic architecture and consequences for fitness
Tietgen, Lukas; Hagen, Ingerid Julie; Kleven, Oddmund; Di Bernardi, Cecilia; Kvalnes, Thomas; Norén, Karin; Hasselgren, Malin; Wallen, Johan Fredrik; Angerbjörn, Anders; Landa, Arild; Eide, Nina Elisabeth; Flagstad, Øystein; Jensen, Henrik (Journal article; Peer reviewed, 2021)Genome-wide association studies provide good opportunities for studying the genetic basis of adaptive traits in wild populations. Yet, previous studies often failed to identify major effect genes. In this study, we used ... -
Genetic architecture and heritability of early-life telomere length in a wild passerine
Pepke, Michael Le; Kvalnes, Thomas; Lundregan, Sarah; Boner, Winnie; Monaghan, Pat; Sæther, Bernt-Erik; Jensen, Henrik; Ringsby, Thor Harald (Peer reviewed; Journal article, 2021)Early-life telomere length (TL) is associated with fitness in a range of organisms. Little is known about the genetic basis of variation in TL in wild animal populations, but to understand the evolutionary and ecological ... -
Harvest-induced phenotypic selection in an island population of moose, Alces alces
Kvalnes, Thomas; Sæther, Bernt-Erik; Haanes, Hallvard; Røed, Knut; Engen, Steinar; Solberg, Erling Johan (Journal article; Peer reviewed, 2016)Empirical evidence strongly indicates that human exploitation has frequently led to rapid evolutionary changes in wild populations, yet the mechanisms involved are often poorly understood. Here, we applied a recently ... -
Inbreeding is associated with shorter early-life telomere length in a wild passerine
Pepke, Michael Le; Niskanen, Alina Katariina; Kvalnes, Thomas; Boner, Winnie; Sæther, Bernt-Erik; Ringsby, Thor Harald; Jensen, Henrik (Peer reviewed; Journal article, 2022)Inbreeding can have negative effects on survival and reproduction, which may be of conservation concern in small and isolated populations. However, the physiological mechanisms underlying inbreeding depression are not ... -
Inferences of genetic architecture of bill morphology in house sparrow using a high-density SNP array point to a polygenic basis
Lundregan, Sarah; Hagen, Ingerid Julie; Gohli, Jostein; Niskanen, Alina Katariina; Kemppainen, Petri; Ringsby, Thor Harald; Kvalnes, Thomas; Pärn, Henrik; Rønning, Bernt; Holand, Håkon; Ranke, Peter Sjolte; Båtnes, Anna Solvang; Selvik, Linn-Karina M.; Lien, Sigbjørn; Sæther, Bernt-Erik; Husby, Arild; Jensen, Henrik (Journal article; Peer reviewed, 2018)Understanding the genetic architecture of quantitative traits can provide insights into the mechanisms driving phenotypic evolution. Bill morphology is an ecologically important and phenotypically variable trait, which is ... -
Insights into the genetic architecture of morphological and sexually selected traits in two passerine bird species
Silva, Catarina; McFarlane, S. Eryn; Hagen, Ingerid Julie; Rönnegård, Lars; Billing, Anna; Kvalnes, Thomas; Kemppainen, Petri; Rønning, Bernt; Ringsby, Thor Harald; Sæther, Bernt-Erik; Qvarnström, Anna; Ellegren, Hans; Jensen, Henrik; Husby, Arild (Journal article; Peer reviewed, 2017)Knowledge about the underlying genetic architecture of phenotypic traits is needed to understand and predict their evolutionary dynamics. The number of causal loci underlying most phenotypic traits, the magnitude of their ... -
Longitudinal telomere dynamics within natural lifespans of a wild bird
Pepke, Michael Le; Kvalnes, Thomas; Wright, Jonathan; Araya Ajoy, Yimen Gerardo; Ranke, Peter Sjolte; Boner, Winnie; Monaghan, Pat; Sæther, Bernt-Erik; Jensen, Henrik; Ringsby, Thor Harald (Peer reviewed; Journal article, 2023)Telomeres, the nucleotide sequences that protect the ends of eukaryotic chromosomes, shorten with each cell division and telomere loss may be influenced by environmental factors. Telomere length (TL) decreases with age in ...