Dennis Hasselquist
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Assortative breeding experiment in a songbird suggests telomere length is determined during early life rather than at conception Open
Telomere length (TL) early in life often shows high heritability and may predict telomere shortening later in life and life expectancy. Yet, there is limited data about what influences TL and TL change at early developmental stages. It is …
Evolution of population‐specific migration routes in the great reed warbler <i>Acrocephalus arundinaceus</i> – evidence of a novel spring migration strategy Open
The migration patterns of birds breeding at high latitudes have undergone major changes during the Holocene, as species expanded from small refugia following the last glaciation. Unique features of genetic migration programs and species‐sp…
Male-biased recombination at chromosome ends in a songbird revealed by precisely mapping crossover positions Open
Recombination plays a crucial role in evolution by generating novel haplotypes and disrupting linkage between genes, thereby enhancing the efficiency of selection. Here, we analyze the genomes of 12 great reed warblers (Acrocephalus arundi…
Male-biased recombination at chromosome ends in a songbird revealed by precisely mapping crossover positions Open
Recombination plays a crucial role in evolution by generating novel haplotypes and disrupting linkage between genes, thereby enhancing the efficiency of selection. Here, we analyse the genomes of twelve great reed warblers ( Acrocephalus a…
Why and when should organisms elongate their telomeres? Elaborations on the ‘excess resources elongation’ and ‘last resort elongation’ hypotheses Open
Telomere length and telomere shortening are thought to be critical cellular attributes and processes that are related to an individual's life span and fitness. The general pattern across most taxa is that after birth telomere length gradua…
Evidence of Site-Specific and Male-Biased Germline Mutation Rate in a Wild Songbird Open
Germline mutations are the ultimate source of genetic variation and the raw material for organismal evolution. Despite their significance, the frequency and genomic locations of mutations, as well as potential sex bias, are yet to be widel…
Solar heating may explain extreme diel flight altitude changes in migrating birds Open
Great reed warblers, Acrocephalus arundinaceus,1 and great snipes, Gallinago media,2 exhibit a diel cycle in flight altitudes-flying much higher during the day than the night-when performing migratory flights covering both night and day. O…
Assessment of avian health status: suitability and constraints of the Zoetis VetScan VS2 blood analyser for ecological and evolutionary studies Open
Biochemical analyses of blood can decipher physiological conditions of living animals and unravel mechanistic underpinnings of life-history strategies and trade-offs. Yet, researchers in ecology and evolution often face constraints in whic…
View article: Female reed warblers in social pairs with low MHC dissimilarity achieve higher MHC compatibility through random extra-pair matings
Female reed warblers in social pairs with low MHC dissimilarity achieve higher MHC compatibility through random extra-pair matings Open
Major Histocompatibility Complex (MHC) polymorphism is maintained by balancing selection through host-pathogen interactions and mate choice. MHC-based mate choice has been proposed across a wide range of vertebrates. However, the likelihoo…
Size and immune function as predictors of predation risk in nestling and newly fledged jackdaws Open
Prey choice by predators may be based on the potential prey's condition, for example resulting in substandard individuals running a higher risk of being predated. Over 5 years, we studied young jackdaws, Corvus monedula, to determine wheth…
Early and Late Migrating Avian Individuals Differ in Constitutive Immune Function and Blood Parasite Infections – But Patterns Depend on the Migratory Strategy Open
Billions of birds migrate every year. To conduct a successful migration, birds undergo a multitude of physiological adaptions. One such adaptation includes adjustments of immune function, however, little is known about intraspecies (betwee…
View article: <scp>MHCtools</scp> – an R package for <scp>MHC</scp> high‐throughput sequencing data: Genotyping, haplotype and supertype inference, and downstream genetic analyses in non‐model organisms
<span>MHCtools</span> – an R package for <span>MHC</span> high‐throughput sequencing data: Genotyping, haplotype and supertype inference, and downstream genetic analyses in non‐model organisms Open
The major histocompatibility complex (MHC) plays a central role in the vertebrate adaptive immune system and has been of long‐term interest in evolutionary biology. While several protocols have been developed for MHC genotyping, there is a…
Telomeres in ecology and evolution: A review and classification of hypotheses Open
Research on telomeres in the fields of ecology and evolution has been rapidly expanding over the last two decades. This has resulted in the formulation of a multitude of, often name‐given, hypotheses related to the associations between tel…
View article: Avian Neo-Sex Chromosomes Reveal Dynamics of Recombination Suppression and W Degeneration
Avian Neo-Sex Chromosomes Reveal Dynamics of Recombination Suppression and W Degeneration Open
How the avian sex chromosomes first evolved from autosomes remains elusive as 100 million years (My) of divergence and degeneration obscure their evolutionary history. The Sylvioidea group of songbirds is interesting for understanding avia…
Seasonally divided moult in the Barred Warbler (<i>Sylvia nisoria</i>) is an endogenously controlled strategy Open
The seasonal timing of moult in migratory birds is an adaptation to cope with time constraints in the annual cycle. Kiat and Izhaki analysed moult patterns in Palaearctic passerines and rejected the proposition that seasonally divided moul…
The Accumulating Costs Hypothesis—to Better Understand Delayed “Hidden” Costs of Seemingly Mild Disease and Other Moderate Stressors Open
Mild diseases and moderate stressors are seemingly harmless and are therefore often assumed to have negligible impact on Darwinian fitness. Here we argue that the effects of “benign” parasites and other moderate stressors may have a greate…
Individual and sex‐related patterns of prolonged flights during both day and night by great reed warblers crossing the Mediterranean Sea and Sahara Desert Open
A wide variety of the barrier crossing strategies exist among migrating songbirds, ranging from strict nocturnal flights to non‐stop flights over a few days. We evaluate barrier crossing strategies in a nocturnally migrating songbird cross…
Population-specific assessment of carry-over effects across the range of a migratory songbird Open
Annual cycle events may be interlinked, influence following annual cycle stages and may alter performance of individuals. Such links, called carry-over effects, can explain individual variation in timing or reproductive success in migrator…
View article: Genomics of an avian neo-sex chromosome reveals the evolutionary dynamics of recombination suppression and sex-linked genes
Genomics of an avian neo-sex chromosome reveals the evolutionary dynamics of recombination suppression and sex-linked genes Open
How the avian sex chromosomes first evolved from autosomes remains elusive as 100 million years (Myr) of divergence and degeneration obscure their evolutionary history. Sylvioidea songbirds is an emerging model for understanding avian sex …
View article: Explaining prevalence, diversity and host specificity in a community of avian haemosporidian parasites
Explaining prevalence, diversity and host specificity in a community of avian haemosporidian parasites Open
Many hypotheses attempt to explain parasite–host associations, but rarely are they examined together in a single community. For hosts, key traits are the proportion of infected individuals (prevalence) and the diversity of parasites infect…
View article: Non-random association of MHC-I alleles in favor of high diversity haplotypes in wild songbirds revealed by computer-assisted MHC haplotype inference using the R package MHCtools
Non-random association of MHC-I alleles in favor of high diversity haplotypes in wild songbirds revealed by computer-assisted MHC haplotype inference using the R package MHCtools Open
Major histocompatibility complex (MHC) genes play a central role for pathogen recognition by the adaptive immune system. The MHC genes are often duplicated and tightly linked within a small genomic region. This structural organization sugg…
View article: Data from: Non-random association of MHC-I alleles in favor of high diversity haplotypes in wild songbirds revealed by computer-assisted MHC haplotype inference using the R package MHCtools
Data from: Non-random association of MHC-I alleles in favor of high diversity haplotypes in wild songbirds revealed by computer-assisted MHC haplotype inference using the R package MHCtools Open
Data set from: Roved J., Hansson B., Stervander, M., Hasselquist D., & Westerdahl H. (2020). Non-random association of MHC-I alleles in favor of high diversity haplotypes in wild songbirds revealed by computer-assisted MHC haplotype infere…
View article: Data from: Non-random association of MHC-I alleles in favor of high diversity haplotypes in wild songbirds revealed by computer-assisted MHC haplotype inference using the R package MHCtools
Data from: Non-random association of MHC-I alleles in favor of high diversity haplotypes in wild songbirds revealed by computer-assisted MHC haplotype inference using the R package MHCtools Open
Data set from: Roved J., Hansson B., Stervander, M., Hasselquist D., & Westerdahl H. (2020). Non-random association of MHC-I alleles in favor of high diversity haplotypes in wild songbirds revealed by computer-assisted MHC haplotype infere…
View article: Wetter climates select for higher immune gene diversity in resident, but not migratory, songbirds
Wetter climates select for higher immune gene diversity in resident, but not migratory, songbirds Open
Pathogen communities can vary substantially between geographical regions due to different environmental conditions. However, little is known about how host immune systems respond to environmental variation across macro-ecological and evolu…
Supplementary Table from Wetter climates select for higher immune gene diversity in resident, but not migratory, songbirds. Open
Tables containing details of all species used, raw data and the full results of all statistical analyses performed.
Supplementary Table from Wetter climates select for higher immune gene diversity in resident, but not migratory, songbirds Open
Tables containing details of all species used, raw data and the full results of all statistical analyses performed.
Population-specific assessment of carry-over effects across the range of a migratory songbird Open
Abstract Annual cycle events may be interlinked, influence following annual cycle stages, and may alter performance of individuals. Such links, called carry-over effects, can explain individual variation in timing or reproductive success i…
Resting metabolic rate in migratory and non‐migratory geese following range expansion: go south, go low Open
While many species suffer from human activities, some like geese benefit and may show range expansions. In some cases geese (partially) gave up migration and started breeding at wintering and stopover grounds. Range expansion may be facili…
Testing the resource tradeoff hypothesis for carotenoid-based signal honesty using genetic variants of the domestic canary Open
Carotenoid-based coloration in birds is widely considered an honest signal of individual condition, but the mechanisms responsible for condition dependency in such ornaments remain debated. Currently, the most common explanation for how ca…