Browsing Naturhistorisk museum by Author "Johnsen, Arild"

Now showing items 1-20 of 32

  • Deep sympatric mitochondrial divergence without reproductive isolation in the common redstart Phoenicurus phoenicurus 
    Hogner, Silje; Laskemoen, Terje; Lifjeld, Jan Terje; Porkert, Jiri; Kleven, Oddmund; Albayrak, Tamer; Kabasakal, Bekir; Johnsen, Arild (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)
    Mitochondrial DNA usually shows low sequence variation within and high sequence divergence among species, which makes it a useful marker for phylogenetic inference and DNA barcoding. A previous study on the common redstart ...
  • Do female bluethroats without extra-pair offspring have more MHC-compatible social mates? 
    Rekdal, Silje Larsen; Anmarkrud, Jarl Andreas; Lifjeld, Jan Terje; Johnsen, Arild (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    Abstract Genes of the major histocompatibility complex (MHC) are crucial for adaptive immunity in jawed vertebrates, and theory predicts that there should be mate choice for optimizing MHC constitution in the ...
  • Effects of fixatives and storage duration on avian sperm morphology 
    Grønstøl, Gaute; Danielsen, Marie; Cramer, Becky; Johannessen, Lars Erik; Johnsen, Arild; Whittington, Emma; Lifjeld, Jan Terje (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2022)
    Abstract Sperm cells are variable both within and among species. To be able to accurately measure sperm cells and understand their function, it is important that sperm cells are preserved in a manner that maintains their ...
  • Elevated phytohaemagglutinin‐induced skin‐swelling response at an intermediate number of MHC class II alleles in bluethroat nestlings 
    Rekdal, Silje Larsen; Anmarkrud, Jarl Andreas; Lifjeld, Jan Terje; Johnsen, Arild (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    Genes of the major histocompatibility complex (MHC) are crucial for adaptive immunity, and theory predicts that the optimal number of alleles is intermediate rather than maximal. Support for such an intermediate optimum ...
  • Endless forms of sexual selection 
    Lindsay, Willow R.; Andersson, Staffan; Bererhi, Badreddine; Höglund, Jacob; Johnsen, Arild; Kvarnemo, Charlotta; Leder, Erica H.; Lifjeld, Jan Terje; Ninnes, Calum E.; Olsson, Mats; Parker, Geoff A.; Pizzari, Tommaso; Qvarnström, Anna; Safran, Rebecca J.; Svensson, Ola; Edwards, Scott V. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    In recent years, the field of sexual selection has exploded, with advances in theoretical and empirical research complementing each other in exciting ways. This perspective piece is the product of a “stock-taking” workshop ...
  • Evolution of female promiscuity in Passerides songbirds 
    Lifjeld, Jan T; Gohli, Jostein; Albrecht, Tomáš; Garcia-del-Rey, Eduardo; Johannessen, Lars E; Kleven, Oddmund; Marki, Petter Z; Omotoriogun, Taiwo C; Rowe, Melissah; Johnsen, Arild (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    Background Female promiscuity is highly variable among birds, and particularly among songbirds. Comparative work has identified several patterns of covariation with social, sexual, ecological and life history ...
  • Evolutionary divergences in Luscinia svecica subspecies complex - New evidence supporting the uniqueness of the Iberian bluethroat breeding populations 
    Garcia, Javier; Johnsen, Arild; Fuertes, Benito; Suarez-Seoane, Susana (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    The assessment of evolutionary divergences within subspecies complexes provide an effective short-cut for estimating intraspecific genetic diversity, which is relevant for conservation actions. We explore new evidence ...
  • Experimental evidence for ovarian hypofunction in sparrow hybrids 
    Eroukhmanoff, Fabrice; Rowe, Melissah; Cramer, Emily R A; Haas, Fredrik; Hermansen, Jo S; Runemark, Anna; Johnsen, Arild; Sætre, Glenn-Peter (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2016)
    Background Postzygotic isolation in the form of reduced viability and/or fertility of hybrids may help maintain species boundaries in the face of interspecific gene flow. Past hybridization events between ...
  • Extra‐pair mating in a passerine bird with highly duplicated major histocompatibility complex class II: Preference for the golden mean 
    Rekdal, Silje Larsen; Anmarkrud, Jarl Andreas; Lifjeld, Jan Terje; Johnsen, Arild (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2019)
    Genes of the major histocompatibility complex (MHC) are essential in vertebrate adaptive immunity, and they are highly diverse and duplicated in many lineages. While it is widely established that pathogen‐mediated selection ...
  • Genetic diversity and sperm characteristics are not associated in two bluethroat (Luscinia svecica) populations 
    Johnsen, Arild; Dobbe, Kristine; Sætre, Camilla Lo Cascio; Eybert, Marie-Christine; Marquet, Matthieu; Bonnet, Patrick; Cramer, Becky (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2023)
    Individual heterozygosity may influence the expression of fitness‐related traits, via genome‐wide or local genetic effects. Earlier studies have shown negative relationships between heterozygosity and sperm variation, ...
  • Genomic evidence of speciation reversal in ravens 
    Kearns, Anna Marika; Restani, Marco; Szabo, Ildiko; Schrøder-Nielsen, Audun; Kim, Jin Ah; Richardson, Hayley M.; Marzluff, John M.; Fleischer, Robert C.; Johnsen, Arild; Omland, Kevin E. (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2018)
    Many species, including humans, have emerged via complex reticulate processes involving hybridisation. Under certain circumstances, hybridisation can cause distinct lineages to collapse into a single lineage with an admixed ...
  • Increased divergence but reduced variation on the Z chromosome relative to autosomes in Ficedula flycatchers: differential introgression or the faster-Z effect? 
    Hogner, Silje; Sæther, Stein Are; Borge, Thomas; Bruvik, Torbjørn; Johnsen, Arild; Sætre, Glenn-Peter (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2012)
    Recent multilocus studies of congeneric birds have shown a pattern of elevated interspecific divergence on the Z chromosome compared to the autosomes. In contrast, intraspecifically, birds exhibit less polymorphism on the ...
  • Is telomere length associated with mate choice in a songbird with a high rate of extrapair paternity? 
    Johnsen, Arild; Pauliny, Angela; Lifjeld, Jan Terje; Blomqvist, Donald (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    Telomere length is related to aging in many eukaryotes and the rate of telomere attrition has been suggested to reflect individual genetic quality. Telomere length could thus have implications for mate choice. We investigated ...
  • Longer Sperm Swim More Slowly in the Canary Islands Chiffchaff 
    Cramer, Emily Rebecca A; Garcia-del-Rey, Eduardo; Johannessen, Lars Erik; Laskemoen, Terje; Marthinsen, Gunnhild; Johnsen, Arild; Lifjeld, Jan Terje (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    Sperm swimming performance affects male fertilization success, particularly in species with high sperm competition. Understanding how sperm morphology impacts swimming performance is therefore important. Sperm swimming ...
  • Measuring sperm swimming performance in birds: effects of dilution, suspension medium, mechanical agitation, and sperm number 
    Cramer, Emily Rebecca A; Rowe, Melissah; Eroukhmanoff, Fabrice; Lifjeld, Jan Terje; Sætre, Glenn-Peter; Johnsen, Arild (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2019)
    Sperm swimming performance, including swimming speed and the proportion of motile cells, may strongly affect fertilization success. However, little is known about how methodological factors affect in vitro measurement of ...
  • Molecular evolution of the pDo500 satellite DNA family in Dolichopoda cave crickets (Rhaphidophoridae) 
    Martinsen, Lene; Venanzetti, Federica; Johnsen, Arild; Sbordoni, Valerio; Bachmann, Lutz (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2009)
    Background Non-coding satellite DNA (satDNA) usually has a high turn-over rate frequently leading to species specific patterns. However, some satDNA families evolve more slowly and can be found in several ...
  • Molecular phylogeny of Allodia (Diptera: Mycetophilidae) constructed using genome skimming 
    Magnussen, Trude; Johnsen, Arild; Kjærandsen, Jostein; Struck, Torsten H; Søli, Geir Einar Ellefsen (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2021)
    In this study, we use low-coverage shotgun sequencing of genomic DNA, commonly referred to as genome skimming, to investigate the phylogenetic relationships of the fungus gnat genus Allodia Winnertz (Mycetophilidae, ...
  • Phylogenetic footprinting of non-coding RNA: hammerhead ribozyme sequences in a satellite DNA family of Dolichopoda cave crickets (Orthoptera, Rhaphidophoridae) 
    Martinsen, Lene; Johnsen, Arild; Venanzetti, Federica; Bachmann, Lutz (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2010)
    Background The great variety in sequence, length, complexity, and abundance of satellite DNA has made it difficult to ascribe any function to this genome component. Recent studies have shown that satellite ...
  • Sequencing of the complete mitochondrial genome of the common raven Corvus corax (Aves: Corvidae) confirms mitogenome-wide deep lineages and a paraphyletic relationship with the Chihuahuan raven C. cryptoleucus 
    Johnsen, Arild; Kearns, Anna Marika; Omland, Kevin E.; Anmarkrud, Jarl Andreas (Journal article / Tidsskriftartikkel / PublishedVersion; Peer reviewed, 2017)
    Previous studies based on single mitochondrial markers have shown that the common raven (Corvus corax) consists of two highly diverged lineages that are hypothesised to have undergone speciation reversal upon secondary ...
  • Signatures of diversifying selection and convergence acting on passerine Toll-like receptor 4 in an evolutionary context 
    Králová, Tereza; Albrecht, Tomas; Bryja, Josef; Horák, David; Johnsen, Arild; Lifjeld, Jan Terje; Novotny, Marian; Sedlacek, Ondrej; Velova, Hana; Vinkler, Michal (Journal article / Tidsskriftartikkel / AcceptedVersion; Peer reviewed, 2018)
    Positive selection acting on Toll‐like receptors (TLRs) has been recently investigated to reveal evolutionary mechanisms of host–pathogen molecular co‐adaptation. Much of this research, however, has focused mainly on the ...