| 1. |
- Große Ruse, Mareile, et al.
(författare)
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Automated analysis of song structure in complex birdsongs
- 2016
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Ingår i: Animal Behaviour. - : Elsevier BV. - 0003-3472. ; 112, s. 39-51
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Tidskriftsartikel (refereegranskat)abstract
- Understanding communication and signalling has long been strived for in studies of animal behaviour. Many songbirds have a variable and complex song, closely connected to territory defence and reproductive success. However, the quantification of such variable song is challenging. In this paper, we present a novel, automated method for detection and classification of syllables in birdsong. The method provides a tool for pairwise comparison of syllables with the aim of grouping them in terms of their similarity. This allows analyses such as (1) determining repertoire size within an individual, (2) comparing song similarity between individuals within as well as between populations of a species and (3) comparing songs of different species (e.g. for species recognition). Our method is based on a particular feature representation of song units (syllables) which ensures invariance to shifts in time, frequency and amplitude. Using a single song from a great reed warbler, Acrocephalus arundinaceus, recorded in the wild, the proposed algorithm is evaluated by means of comparison to manual auditory and visual (spectrogram) song investigation by a human expert and to standard song analysis methods. Our birdsong analysis approach conforms well to manual classification and, moreover, outperforms the hitherto widely used methods based on mel-frequency cepstral coefficients and spectrogram cross-correlation. Thus, our algorithm is a methodological step forward for analyses of song (syllable) repertoires of birds singing with high complexity.
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| 2. |
- Hagen, Ingerid J., et al.
(författare)
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A genome-wide linkage map for the house sparrow (Passer domesticus) provides insights into the evolutionary history of the avian genome
- 2020
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Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; 20:2, s. 544-559
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Tidskriftsartikel (refereegranskat)abstract
- The house sparrow is an important model species for studying physiological, ecological and evolutionary processes in wild populations. Here, we present a medium density, genome wide linkage map for house sparrow (Passer domesticus) that has aided the assembly of the house sparrow reference genome, and that will provide an important resource for ongoing mapping of genes controlling important traits in the ecology and evolution of this species. Using a custom house sparrow 10 K iSelect Illumina SNP chip we have assigned 6,498 SNPs to 29 autosomal linkage groups, based on a mean of 430 informative meioses per SNP. The map was constructed by combining the information from linkage with that of the physical position of SNPs within scaffold sequences in an iterative process. Averaged between the sexes; the linkage map had a total length of 2,004 cM, with a longer map for females (2,240 cM) than males (1,801 cM). Additionally, recombination rates also varied along the chromosomes. Comparison of the linkage map to the reference genomes of zebra finch, collared flycatcher and chicken, showed a chromosome fusion of the two avian chromosomes 8 and 4A in house sparrow. Lastly, information from the linkage map was utilized to conduct analysis of linkage disequilibrium (LD) in eight populations with different effective population sizes (Ne) in order to quantify the background level LD. Together, these results aid the design of future association studies, facilitate the development of new genomic tools and support the body of research that describes the evolution of the avian genome.
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| 3. |
- Hansson, Bengt, et al.
(författare)
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Contrasting results from GWAS and QTL mapping on wing length in great reed warblers
- 2018
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Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; 18:4, s. 867-876
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Tidskriftsartikel (refereegranskat)abstract
- A major goal in evolutionary biology is to understand the genetic basis of adaptive traits. In migratory birds, wing morphology is such a trait. Our previous work on the great reed warbler (Acrocephalus arundinaceus) shows that wing length is highly heritable and under sexually antagonistic selection. Moreover, a quantitative trait locus (QTL) mapping analysis detected a pronounced QTL for wing length on chromosome 2, suggesting that wing morphology is partly controlled by genes with large effects. Here, we re-evaluate the genetic basis of wing length in great reed warblers using a genomewide association study (GWAS) approach based on restriction site-associated DNA sequencing (RADseq) data. We use GWAS models that account for relatedness between individuals and include covariates (sex, age and tarsus length). The resulting association landscape was flat with no peaks on chromosome 2 or elsewhere, which is in line with expectations for polygenic traits. Analysis of the distribution of p-values did not reveal biases, and the inflation factor was low. Effect sizes were however not uniformly distributed on some chromosomes, and the Z chromosome had weaker associations than autosomes. The level of linkage disequilibrium (LD) in the population decayed to background levels within c. 1 kbp. There could be several reasons to why our QTL study and GWAS gave contrasting results including differences in how associations are modelled (cosegregation in pedigree vs. LD associations), how covariates are accounted for in the models, type of marker used (multi- vs. biallelic), difference in power or a combination of these. Our study highlights that the genetic architecture even of highly heritable traits is difficult to characterize in wild populations.
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| 4. |
- Hansson, Bengt, et al.
(författare)
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Hybridization but no evidence for backcrossing and introgression in a sympatric population of great reed warblers and clamorous reed warblers.
- 2012
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:2
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Tidskriftsartikel (refereegranskat)abstract
- Hybridization is observed frequently in birds, but often it is not known whether the hybrids are fertile and if backcrossing occurs. The breeding ranges of the great reed warbler (Acrocephalus arundinaceus) and the clamorous reed warbler (A. stentoreus) overlap in southern Kazakhstan and a previous study has documented hybridization in a sympatric population. In the present study, we first present a large set of novel microsatellite loci isolated and characterised in great reed warblers. Secondly, we evaluate whether hybridization in the sympatric breeding population has been followed by backcrossing and introgression.We isolated 181 unique microsatellite loci in great reed warblers. Of 41 loci evaluated, 40 amplified and 30 were polymorphic. Bayesian clustering analyses based on genotype data from 23 autosomal loci recognised two well-defined genetic clusters corresponding to the two species. Individuals clustered to a very high extent to either of these clusters (admixture proportions ≥0.984) with the exception of four previously suggested arundinaceus-stentoreus hybrid birds that showed mixed ancestry (admixture proportions 0.495-0.619). Analyses of simulated hybrids and backcrossed individuals showed that the sampled birds do not correspond to first-fourth-generation backcrosses, and that fifth or higher generation backcrosses to a high extent resemble 'pure' birds at this set of markers.We conclude that these novel microsatellite loci provide a useful molecular resource for Acrocephalus warblers. The time to reach reproductive isolation is believed to be very long in birds, approximately 5 Myrs, and with an estimated divergence time of 2 Myrs between these warblers, some backcrossing and introgression could have been expected. However, there was no evidence for backcrossing and introgression suggesting that hybrids are either infertile or their progeny inviable. Very low levels of introgression cannot be excluded, which still may be an important factor as a source of new genetic variation.
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| 5. |
- Hansson, Bengt, et al.
(författare)
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Postglacial colonisation patterns and the role of isolation and expansion in driving diversification in a passerine bird.
- 2008
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:7
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Tidskriftsartikel (refereegranskat)abstract
- Pleistocene glacial cycles play a major role in diversification and speciation, although the relative importance of isolation and expansion in driving diversification remains debated. We analysed mitochondrial DNA sequence data from 15 great reed warbler (Acrocephalus arundinaceus) populations distributed over the vast Eurasian breeding range of the species, and revealed unexpected postglacial expansion patterns from two glacial refugia. There were 58 different haplotypes forming two major clades, A and B. Clade A dominated in Western Europe with declining frequencies towards Eastern Europe and the Middle East, but showed a surprising increase in frequency in Western and Central Asia. Clade B dominated in the Middle East, with declining frequencies towards north in Central and Eastern Europe and was absent from Western Europe and Central Asia. A parsimonious explanation for these patterns is independent postglacial expansions from two isolated refugia, and mismatch distribution analyses confirmed this suggestion. Gene flow analyses showed that clade A colonised both Europe and Asia from a refugium in Europe, and that clade B expanded much later and colonised parts of Europe from a refugium in the Middle East. Great reed warblers in the eastern parts of the range have slightly paler plumage than western birds (sometimes treated as separate subspecies; A. a. zarudnyi and A. a. arundinaceus, respectively) and our results suggest that the plumage diversification took place during the easterly expansion of clade A. This supports the postglacial expansion hypothesis proposing that postglacial expansions drive diversification in comparatively short time periods. However, there is no indication of any (strong) reproductive isolation between clades and our data show that the refugia populations became separated during the last glaciation. This is in line with the Pleistocene speciation hypothesis invoking that much longer periods of time in isolation are needed for speciation to occur.
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| 6. |
- Hasselquist, Dennis, et al.
(författare)
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Individual consistency of long-distance migration in a songbird: significant repeatability of autumn route, stopovers and wintering sites but not in timing of migration
- 2017
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Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857. ; 48:1, s. 91-102
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Tidskriftsartikel (refereegranskat)abstract
- Through new tracking techniques, data on timing and routes of migration in long-distance migrant birds are accumulating. However, studies of the consistency of migration of the same individuals between years are still rare in small-sized passerine birds. This type of information is important to understand decisions and migration abilities at the individual level, but also for life history theory, for understanding carry over effects between different annual cycle stages and for conservation. We analysed individual repeatability of migration between years in great reed warblers Acrocephalus arundinaceus; a medium-sized European songbird migrating to sub-Saharan Africa. In seven males, with geolocator data from 2–4 yr per bird, we found low to moderate (non significant) repeatability in timing of migration parameters (R ≤ 0.41), but high (and significant) repeatability for most spatial parameters, i.e. autumn route (R = 0.64) and stopover sites (R = 0.59–0.87) in Europe, and wintering sites (R = 0.77–0.99) in sub-Saharan Africa. This pattern of high spatial but low temporal within-individual repeatability of migration between years contrasts other tracking studies of migrating birds that generally have found consistency in timing but flexibility in routes. High spatial consistency of migration in the great reed warbler may be due to it being a specialist in wetlands, an unevenly distributed habitat, favouring a strategy of recurrence at previously visited sites. Low temporal repeatability may be caused by large between-year variation in carry-over effects from the breeding season, high flexibility in decision rules during migration or high sensitivity to environmental factors (weather, wind) during migration.
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| 7. |
- Hämäläinen, Anni, et al.
(författare)
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Evolution of sex-specific pace-of-life syndromes : causes and consequences
- 2018
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 72:3
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Forskningsöversikt (refereegranskat)abstract
- Males and females commonly differ in their life history optima and, consequently, in the optimal expression of life history, behavioral and physiological traits involved in pace-of-life syndromes (POLS). Sex differences in mean trait expression typically result if males and females exhibit different fitness optima along the same pace-of-life continuum, but the syndrome structure may also differ for the sexes. Due to sex-specific selective pressures imposed by reproductive roles and breeding strategies, the sexes may come to differ in the strength of correlation among traits, or different traits may covary in males and females. Ignorance of these selective forces operating between and within the sexes may lead to flawed conclusions about POLS manifestation in the species, and stand in the way of understanding the evolution, maintenance, and variability of POLS. We outline ways in which natural and sexual selection influence sex-specific trait evolution, and describe potential ultimate mechanisms underlying sex-specific POLS. We make predictions on how reproductive roles and the underlying sexual conflict lead to sex-specific trait covariances. These predictions lead us to conclude that sexual dimorphism in POLS is expected to be highly prevalent, allow us to assess possible consequences for POLS evolution, and provide guidelines for future studies.
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| 8. |
- Immonen, Elina, et al.
(författare)
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Evolution of sex-specific pace-of-life syndromes : genetic architecture and physiological mechanisms
- 2018
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 72:3
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Forskningsöversikt (refereegranskat)abstract
- Sex differences in life history, physiology, and behavior are nearly ubiquitous across taxa, owing to sex-specific selection that arises from different reproductive strategies of the sexes. The pace-of-life syndrome (POLS) hypothesis predicts that most variation in such traits among individuals, populations, and species falls along a slow-fast pace-of-life continuum. As a result of their different reproductive roles and environment, the sexes also commonly differ in pace-of-life, with important consequences for the evolution of POLS. Here, we outline mechanisms for how males and females can evolve differences in POLS traits and in how such traits can covary differently despite constraints resulting from a shared genome. We review the current knowledge of the genetic basis of POLS traits and suggest candidate genes and pathways for future studies. Pleiotropic effects may govern many of the genetic correlations, but little is still known about the mechanisms involved in trade-offs between current and future reproduction and their integration with behavioral variation. We highlight the importance of metabolic and hormonal pathways in mediating sex differences in POLS traits; however, there is still a shortage of studies that test for sex specificity in molecular effects and their evolutionary causes. Considering whether and how sexual dimorphism evolves in POLS traits provides a more holistic framework to understand how behavioral variation is integrated with life histories and physiology, and we call for studies that focus on examining the sex-specific genetic architecture of this integration.
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| 9. |
- Koleček, Jaroslav, et al.
(författare)
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Cross-continental migratory connectivity and spatiotemporal migratory patterns in the great reed warbler
- 2016
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Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857 .- 1600-048X. ; 47:6, s. 756-767
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Tidskriftsartikel (refereegranskat)abstract
- Migratory connectivity describes to which degree different breeding populations have distinct (non-overlapping) non-breeding sites. Uncovering the level of migratory connectivity is crucial for effective conservation actions and for understanding of the evolution of local adaptations and migratory routes. Here we investigate migration patterns in a passerine bird, the great reed warbler Acrocephalus arundinaceus, over its wide Western Palearctic breeding range using geolocators from Spain, Sweden, Czech Republic, Bulgaria and Turkey. We found moderate migratory connectivity: a highly significant spatial structure in the connections between breeding and sub-Saharan non-breeding grounds, but at the same time a partial overlap between individual populations, particularly along the Gulf of Guinea where the majority of birds from the Spanish, Swedish and Czech populations spent their non-breeding period. The post-breeding migration routes were similar in direction and rather parallel for the five populations. Birds from Turkey showed the most distinctive migratory routes and sub-Saharan non-breeding range, with a post-breeding migration to east Africa and, together with birds from Bulgaria, a previously unknown pre-breeding migration over the Arabian Peninsula indicating counter-clockwise loop migration. The distances between breeding and sub-Saharan non-breeding sites, as well as between first and final sub-Saharan non-breeding sites, differed among populations. However, the total speed of migration did not differ significantly between populations; neither during post-breeding migration in autumn, nor pre-breeding migration in spring. There was also no significant relationship between the total speed of migration and distance between breeding and non-breeding sites (neither post- nor pre-breeding) and, surprisingly, the total speed of migration generally did not differ significantly between post-breeding and pre-breeding migration. Future challenges include understanding whether non-breeding environmental conditions may have influenced the differences in migratory patterns that we observed between populations, and to which extent non-breeding habitat fluctuations and loss may affect population sizes of migrants.
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| 10. |
- Lemke, Hilger, et al.
(författare)
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Annual cycle and migration strategies of a trans-saharan migratory songbird: a geolocator study in the great reed warbler.
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- Recent technological advancements now allow us to obtain geographical position data for a wide range of animal movements. Here we used light-level geolocators to study the annual migration cycle in great reed warblers (Acrocephalus arundinaceus), a passerine bird breeding in Eurasia and wintering in sub-Saharan Africa. We were specifically interested in seasonal strategies in routes and schedules of migration. We found that the great reed warblers (all males, no females were included) migrated from the Swedish breeding site in early August. After spending up to three weeks at scattered stopover sites in central to south-eastern Europe, they resumed migration and crossed the Mediterranean Sea and Sahara Desert without lengthy stopovers. They then spread out over a large overwintering area and each bird utilised two (or even three) main wintering sites that were spatially separated by a distinct mid-winter movement. Spring migration initiation date differed widely between individuals (1-27 April). Several males took a more westerly route over the Sahara in spring than in autumn, and in general there were fewer long-distance travels and more frequent shorter stopovers, including one in northern Africa, in spring. The shorter stopovers made spring migration on average faster than autumn migration. There was a strong correlation between the spring departure dates from wintering sites and the arrival dates at the breeding ground. All males had a high migration speed in spring despite large variation in departure dates, indicating a time-minimization strategy to achieve an early arrival at the breeding site; the latter being decisive for high reproductive success in great reed warblers. Our results have important implications for the understanding of long-distance migrants' ability to predict conditions at distant breeding sites and adapt to rapid environmental change.
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| 11. |
- Malmiga, Gintaras, et al.
(författare)
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Individual and sex-related patterns of prolonged flights during both day and night by great reed warblers crossing the Mediterranean Sea and Sahara Desert
- 2021
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Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857 .- 1600-048X. ; 52:1
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Tidskriftsartikel (refereegranskat)abstract
- 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 crossing the Mediterranean Sea and the Sahara Desert, the great reed warbler, exploring variation between the sexes and within individuals. We used data from 31 year-round light-level geolocators tracks from 26 individuals (13 males and 13 females), with four individuals tracked for 2–3.5 consecutive years. Almost all individuals (25 of 26) prolonged their flights into the day at least on one occasion. The mean duration of these prolonged flights was 19.9 h and did not differ between sexes or seasons. Fifteen birds performed non-stop flights during more than one full day and night (≥ 24 h; mean = 31.9 h; max = 55 h) in autumn and/or spring, but these flights were generally too short to cross an entire barrier (such as the Sahara Desert) in one non-stop flight. Patterns of prolonged flights showed considerable within-individual variation in females between seasons (autumn versus spring) and in both males and females between years, suggesting high individual flexibility in migration strategy. Significantly more males than females performed prolonged flights during autumn migration, but not spring, possibly reflecting sex-specific carry-over effects. We conclude that great reed warblers have the ability to conduct prolonged continuous flights for up to several nights and days, which potentially would allow them to cross the Sahara Desert in one non-stop flight. However, they typically use a mixed strategy of several nocturnal flights with intermittent stopovers in combination with 1–3 prolonged flights. Prolonged flights covered less than half (44%) of the total flight time across the barriers, and the diurnal parts of the flights covered only 18% of this time.
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| 12. |
- Morosinotto, Chiara, et al.
(författare)
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Heritability and Parental Effects in Telomere Length in a Color Polymorphic Long-Lived Bird
- 2022
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Ingår i: Physiological and Biochemical Zoology. - : University of Chicago Press. - 1522-2152 .- 1537-5293. ; 95:4, s. 351-364
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Tidskriftsartikel (refereegranskat)abstract
- Relative telomere length (RTL), an indicator of senescence, has been shown to be heritable but can also be affected by environmental factors, such as parental effects. Investigating heritability as well as parental effects and rearing environment can help us to understand the factors affecting offspring telomeres. Moreover, how phenotypic parental traits linked with fitness can impact offspring RTL is still unclear. A phenotypic marker closely associated with physiological traits and fitness is melanin-based color polymorphism, which in tawny owl (Strix aluco) is highly heritable and strongly associated with adult telomere shortening and survival. We studied narrow-sense heritability (h2) of RTL, as well as the impact of parental age and color morph and their interaction on offspring RTL. Offspring RTL at fledging was strongly positively correlated with both mother RTL and father RTL at breeding. Offspring RTL was also negatively associated with father age, suggesting that older fathers sired offspring with shorter telomeres. Parental color morph did not explain offspring RTL, and there were no interactive effects of parental morph and age, despite previously documented morph-specific senescence patterns. Our results suggest that RTL is highly heritable and affected by paternal age but not related to color polymorphism. This suggests that either morph-specific telomere shortening as an adult does not result in significantly shorter telomeres in their gametes, or that parents compensate morph-specific senescence via parental care. Morph-specific patterns of telomere dynamics in polymorphic species may thus emerge from different life history strategies adopted in adulthood.
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| 13. |
- Muhammad, Asghar, et al.
(författare)
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Maternal and genetic factors determine early life telomere length
- 2015
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Ingår i: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 282:1799
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Tidskriftsartikel (refereegranskat)abstract
- In a broad range of species-including humans-it has been demonstrated that telomere length declines throughout life and that it may be involved in cell and organismal senescence. This potential link to ageing and thus to fitness has triggered recent interest in understanding how variation in telomere length is inherited and maintained. However, previous studies suffer from two main drawbacks that limit the possibility of understanding the relative importance of genetic, parental and environmental influences on telomere length variation. These studies have been based on (i) telomere lengths measured at different time points in different individuals, despite the fact that telomere length changes over life, and (ii) parent-offspring regression techniques, which do not enable differentiation between genetic and parental components of inheritance. To overcome these drawbacks, in our study of a songbird, the great reed warbler, we have analysed telomere length measured early in life in both parents and offspring and applied statistical models (so-called 'animal models') that are based on long-term pedigree data. Our results showed a significant heritability of telomere length on the maternal but not on the paternal side, and that the mother's age was positively correlated with their offspring's telomere length. Furthermore, the pedigree-based analyses revealed a significant heritability and an equally large maternal effect. Our study demonstrates strong maternal influence on telomere length and future studies now need to elucidate possible underlying factors, including which types of maternal effects are involved.
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| 14. |
- Radchuk, Viktoriia, et al.
(författare)
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Adaptive responses of animals to climate change are most likely insufficient
- 2019
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Biological responses to climate change have been widely documented across taxa and regions, but it remains unclear whether species are maintaining a good match between phenotype and environment, i.e. whether observed trait changes are adaptive. Here we reviewed 10,090 abstracts and extracted data from 71 studies reported in 58 relevant publications, to assess quantitatively whether phenotypic trait changes associated with climate change are adaptive in animals. A meta-analysis focussing on birds, the taxon best represented in our dataset, suggests that global warming has not systematically affected morphological traits, but has advanced phenological traits. We demonstrate that these advances are adaptive for some species, but imperfect as evidenced by the observed consistent selection for earlier timing. Application of a theoretical model indicates that the evolutionary load imposed by incomplete adaptive responses to ongoing climate change may already be threatening the persistence of species.
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| 15. |
- Roved, Jacob, et al.
(författare)
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Evidence for sexual conflict over major histocompatibility complex diversity in a wild songbird
- 2018
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Ingår i: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 285:1884
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Tidskriftsartikel (refereegranskat)abstract
- Sex differences in parasite load and immune responses are found across a wide range of animals, with females generally having lower parasite loads and stronger immune responses than males. Intrigued by these general patterns, we investigated if there was any sign of sex-specific selection on an essential component of adaptive immunity that is known to affect fitness, the major histocompatibility complex class I (MHC-I) genes, in a 20-year study of great reed warblers. Our analyses on fitness related to MHC-I diversity showed a highly significant interaction between MHC-I diversity and sex, where males with higher, and females with lower, MHC-I diversity were more successful in recruiting offspring. Importantly, mean MHC-I diversity did not differ between males and females, and consequently neither sex reached its MHC-I fitness optimum. Thus, there is an unresolved genetic sexual conflict over MHC-I diversity in great reed warblers. Selection from pathogens is known to maintain MHC diversity, but previous theory ignores that the immune environments are considerably different in males and females. Our results suggest that sexually antagonistic selection is an important, previously neglected, force in the evolution of vertebrate adaptive immunity, and have implications for evolutionary understanding of costs of immune responses and autoimmune diseases.
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| 16. |
- Sandsten, Maria, et al.
(författare)
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A SVD-based classification of bird singing in different time-frequency domains using multitapers
- 2011
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Ingår i: European Signal Processing Conference. - 2219-5491. ; 2011, s. 966-970
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Konferensbidrag (refereegranskat)abstract
- In this paper, a novel method for analysing a bird’s song is presented. The song of male great reed warblers is used for developing and testing the methods. A robust method for detecting syllables is proposed and a classification of those syllables as compared to reference syllables is done. The extraction of classification features are based on the use of singular vectors in different time-frequency domains, such as the ambiguity and the doppler domains, in addition to the usual sonogram. The analysis is also made using multitaper analysis where the Welch method and the Thomson multi- tapers are compared to the more recently proposed locally stationary process multitapers.
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| 17. |
- Sigeman, Hanna, et al.
(författare)
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Avian Neo-Sex Chromosomes Reveal Dynamics of Recombination Suppression and W Degeneration
- 2021
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Ingår i: Molecular biology and evolution. - : Oxford University Press. - 0737-4038 .- 1537-1719. ; 38:12, s. 5275-5291
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Tidskriftsartikel (refereegranskat)abstract
- 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 avian sex chromosome evolution because a chromosome fusion event similar to 24 Ma formed "neo-sex chromosomes" consisting of an added (new) and an ancestral (old) part. Here, we report the complete female genome (ZW) of one Sylvioidea species, the great reed warbler (Acrocephalus arundinaceus). Our long-read assembly shows that the added region has been translocated to both Z and W, and whereas the added-Z has retained its gene order the added-W part has been heavily rearranged. Phylogenetic analyses show that recombination between the homologous added-Z and -W regions continued after the fusion event, and that recombination suppression across this region took several million years to be completed. Moreover, recombination suppression was initiated across multiple positions over the added-Z, which is not consistent with a simple linear progression starting from the fusion point. As expected following recombination suppression, the added-W show signs of degeneration including repeat accumulation and gene loss. Finally, we present evidence for nonrandom maintenance of slowly evolving and dosage-sensitive genes on both ancestral- and added-W, a process causing correlated evolution among orthologous genes across broad taxonomic groups, regardless of sex linkage.
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| 18. |
- Sjöberg, Sissel, et al.
(författare)
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Extreme altitudes during diurnal flights in a nocturnal songbird migrant
- 2021
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 372:6542, s. 646-648
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Tidskriftsartikel (refereegranskat)abstract
- Billions of nocturnally migrating songbirds fly across oceans and deserts on their annual journeys. Using multisensor data loggers, we show that great reed warblers (Acrocephalus arundinaceus) regularly prolong their otherwise strictly nocturnal flights into daytime when crossing the Mediterranean Sea and the Sahara Desert. Unexpectedly, when prolonging their flights, they climbed steeply at dawn, from a mean of 2394 meters above sea level to reach extreme cruising altitudes (mean 5367 and maximum 6267 meters above sea level) during daytime flights. This previously unknown behavior of using exceedingly high flight altitudes when migrating during daytime could be caused by diel variation in ambient temperature, winds, predation, vision range, and solar radiation. Our finding of this notable behavior provides new perspectives on constraints in bird flight and might help to explain the evolution of nocturnal migration.
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| 19. |
- Sjöberg, Sissel, et al.
(författare)
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Solar heating may explain extreme diel flight altitude changes in migrating birds
- 2023
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Ingår i: Current Biology. - 0960-9822. ; 33:19, s. 2-4237
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Tidskriftsartikel (refereegranskat)abstract
- 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. One hypothesis proposed to explain this behavior is that the birds face additional heating by solar radiation during daytime and hence must climb to very high, and thus also very cold, altitudes to avoid overheating during daytime flights.1,2 Yet, solar heat gain in birds has been shown to drastically decrease with wind speed,3,4 and the quantitative heating effect by solar radiation on a bird flying with an airspeed of 10 m/s or more is unknown. We analyzed temperature data from multisensor data loggers (MDLs)5,6 placed without direct exposure to solar radiation on great reed warblers (the logger covered by feathers on the back) and great snipes (the logger on the leg, covered from the sun by the tail). We found that logger temperatures were significantly higher (5.9°C–8.8°C in great reed warblers and 4.8°C–5.4°C in great snipes) during the day than during the night in birds flying at the same altitudes (and thus also the same expected ambient air temperatures). These results strongly indicate that the heat balance of the flying birds is indeed affected by solar radiation, which is in accordance with the hypothesis that solar radiation is a key factor causing the remarkable diel cycles in flight altitude observed in these two long-distance migrant bird species.1,2
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| 20. |
- Tarka, Maja, et al.
(författare)
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A strong quantitative trait locus for wing length on chromosome 2 in a wild population of great reed warblers.
- 2010
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Ingår i: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 1471-2954 .- 0962-8452. ; 277, s. 2361-2369
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Tidskriftsartikel (refereegranskat)abstract
- Wing length is a key character for essential behaviours related to bird flight such as migration and foraging. In the present study, we initiate the search for the genes underlying wing length in birds by studying a long-distance migrant, the great reed warbler (Acrocephalus arundinaceus). In this species wing length is an evolutionary interesting trait with pronounced latitudinal gradient and sex-specific selection regimes in local populations. We performed a quantitative trait locus (QTL) scan for wing length in great reed warblers using phenotypic, genotypic, pedigree and linkage map data from our long-term study population in Sweden. We applied the linkage analysis mapping method implemented in GridQTL (a new web-based software) and detected a genome-wide significant QTL for wing length on chromosome 2, to our knowledge, the first detected QTL in wild birds. The QTL extended over 25 cM and accounted for a substantial part (37%) of the phenotypic variance of the trait. A genome scan for tarsus length (a body-size-related trait) did not show any signal, implying that the wing-length QTL on chromosome 2 was not associated with body size. Our results provide a first important step into understanding the genetic architecture of avian wing length, and give opportunities to study the evolutionary dynamics of wing length at the locus level.
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| 21. |
- Tarka, Maja
(författare)
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Evolutionary dynamics of migration and breeding in wild birds: genetic architecture, sexual conflicts and evolutionary constraints
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Our knowledge of the evolutionary potential of traits involved in different selective episodes, especially in natural populations, is still limited. This is true for questions such as the genetic basis and inheritance of traits, how natural and sexual selection acts on them, and how selective conflicts influence the evolutionary response to selection. In my thesis, I investigate these questions, using a long term study population of great reed warblers (Acrocephalus arundinaceus) with known pedigree, as a model system. I have focused on traits at the interface between migration and breeding and worked both in the field, the DNA lab and used powerful statistical tools in quantitative genetics and quantitative trait locus (QTL) mapping. Moreover, using new technology (geolocators), I describe full migratory paths showing a unique case of small songbirds flying rapidly (probably non-stop), over the Mediterranean Sea and the Sahara Desert, where after birds spread out to winter over a huge range covering the entire sub-Saharan West Africa to the Congo Basin in the east. Early spring arrival to the breeding site is decisive for breeding success in song birds. I found that arrival date is a heritable trait, with higher genetic variance in experienced (≥ 2 year old) as compared with inexperienced (1 year old) birds. Traits are not independent units which can constrain their evolution. However, I found no sign of a morphological ‘migratory syndrome’ (genetic correlations between migration traits) on the population level, and no evolutionary constraint acting through morphology on arrival date. Wing length was negatively correlated with arrival. I found a strong intralocus sexual conflict acting on wing length, where males are selected for long wings and females for short wings. Also I present a large-effect QTL for wing length located on chromosome 2, which recently has been confirmed in the zebra finch, suggesting its generality among birds. I also present a conceptual framework for the study of intralocus sexual conflict. An analysis of 13 traits suggested that traits within a population can be in very different stages of the conflict. I have also investigated potential evolutionary constraints through genetic correlations between traits in ten long-term study populations of wild birds and found evolutionary constraints on morphology, but mainly on current selection. Finally I investigate a potential source of genetic variation in a hybrid zone between great reed warblers and clamorous warblers (A. stentoreus). No sign of introgression was found, suggesting that hybrids are sterile or offspring inviable. These studies make an important contribution to our knowledge of evolutionary dynamics in the wild.
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| 22. |
- Tarka, Maja, et al.
(författare)
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Intralocus sexual conflict over wing length in a wild migratory bird
- 2014
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Ingår i: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 183:1, s. 62-73
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Tidskriftsartikel (refereegranskat)abstract
- Intralocus sexual conflict (ISC) occurs when males and females have different adaptive peaks but are constrained fromevolving sexual dimorphism because of shared genes. Implications of this conflict on evolutionary dynamics in wild populations have not been investigated in detail. In comprehensive analyses of selection, heritability, and genetic correlations, we found evidence for an ISC over wing length, a key trait for flight performance and migration, in a long-term study of wild great reed warblers (Acrocephalus arundinaceus). We found moderate sexual dimorphism, high heritability, moderate sexually antagonistic selection, and strong positive crosssex genetic correlation in wing length, together supporting the presence of ISC. A negative genetic correlation between male wing length and female fitness indicated that females inheriting alleles for longer wings from their male relatives also inherited lower fitness.Moreover, cross-sex genetic correlations imposed constraint on the predicted microevolutionary trajectory of wing length (based on selection gradients), especially in females where the predicted response was reversed. The degree of sexual dimorphism in wing length did not change over time, suggesting no sign of conflict resolution. Our study provides novel insight into how an ISC over a fitness trait can affect microevolution in a wild population under natural selection.
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| 23. |
- Tarka, Maja, et al.
(författare)
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Selection and evolutionary potential of spring arrival phenology in males and females of a migratory songbird
- 2015
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Ingår i: Journal of evolutionary biology. - : Wiley. - 1420-9101 .- 1010-061X. ; 28:5, s. 1024-1038
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Tidskriftsartikel (refereegranskat)abstract
- The timing of annual life-history events affects survival and reproduction of all organisms. A changing environment can perturb phenological adaptations and an important question is if populations can evolve fast enough to track the environmental changes. Yet, little is known about selection and evolutionary potential of traits determining the timing of crucial annual events. Migratory species, which travel between different climatic regions, are particularly affected by global environmental changes. To increase our understanding of evolutionary potential and selection of timing traits, we investigated the quantitative genetics of arrival date at the breeding ground using a multigenerational pedigree of a natural great reed warbler (Acrocephalus arundinaceus) population. We found significant heritability of 16.4% for arrival date and directional selection for earlier arrival in both sexes acting through reproductive success, but not through lifespan. Mean arrival date advanced with 6days over 20years, which is in exact accordance with our predicted evolutionary response based on the breeder's equation. However, this phenotypic change is unlikely to be caused by microevolution, because selection seems mainly to act on the nongenetic component of the trait. Furthermore, demographical changes could also not account for the advancing arrival date. Instead, a strong correlation between spring temperatures and population mean arrival date suggests that phenotypic plasticity best explains the advancement of arrival date in our study population. Our study dissects the evolutionary and environmental forces that shape timing traits and thereby increases knowledge of how populations cope with rapidly changing environments.
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| 24. |
- Tarka, Maja, et al.
(författare)
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Sex differences in life history, behavior, and physiology along a slow-fast continuum : a meta-analysis
- 2018
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 72:8
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Tidskriftsartikel (refereegranskat)abstract
- The pace-of-life syndrome (POLS) hypothesis predicts that behavior and physiology covary with life history. Evidence for such covariation is contradictory, possibly because systematic sources of variation (e.g. sex) have been neglected. Sexes often experience different selection pressures leading to sex-specific allocation between reproduction and self-maintenance, facilitating divergence in life-history. Sex-specific differences in means and possibly variances may therefore play a key role in the POLS framework. We investigate whether sexes differ in means and variances along the fast-slow pace-of-life continuum for life history and physiological and behavioral traits. In addition, we test whether social and environmental characteristics such as breeding strategy, mating system, and study environment explain heterogeneity between the sexes. Using meta-analytic methods, we found that populations with a polygynous mating system or for studies conducted on wild populations, males had a faster pace-of-life for developmental life-history traits (e.g., growth rate), behavior, and physiology. In contrast, adult life-history traits (e.g., lifespan) were shifted towards faster pace-of-life in females, deviating from the other trait categories. Phenotypic variances were similar between the sexes across trait categories and were not affected by mating system or study environment. Breeding strategy did not influence sex differences in variances or means. We discuss our results in the light of sex-specific selection that might drive sex-specific differences in pace-of-life and ultimately POLS.
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| 25. |
- Teplitsky, Celine, et al.
(författare)
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Assessing Multivariate Constraints to Evolution across Ten Long-Term Avian Studies
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:3, s. e90444-
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Tidskriftsartikel (refereegranskat)abstract
- Background: In a rapidly changing world, it is of fundamental importance to understand processes constraining or facilitating adaptation through microevolution. As different traits of an organism covary, genetic correlations are expected to affect evolutionary trajectories. However, only limited empirical data are available. Methodology/Principal Findings: We investigate the extent to which multivariate constraints affect the rate of adaptation, focusing on four morphological traits often shown to harbour large amounts of genetic variance and considered to be subject to limited evolutionary constraints. Our data set includes unique long-term data for seven bird species and a total of 10 populations. We estimate population-specific matrices of genetic correlations and multivariate selection coefficients to predict evolutionary responses to selection. Using Bayesian methods that facilitate the propagation of errors in estimates, we compare (1) the rate of adaptation based on predicted response to selection when including genetic correlations with predictions from models where these genetic correlations were set to zero and (2) the multivariate evolvability in the direction of current selection to the average evolvability in random directions of the phenotypic space. We show that genetic correlations on average decrease the predicted rate of adaptation by 28%. Multivariate evolvability in the direction of current selection was systematically lower than average evolvability in random directions of space. These significant reductions in the rate of adaptation and reduced evolvability were due to a general nonalignment of selection and genetic variance, notably orthogonality of directional selection with the size axis along which most (60%) of the genetic variance is found. Conclusions: These results suggest that genetic correlations can impose significant constraints on the evolution of avian morphology in wild populations. This could have important impacts on evolutionary dynamics and hence population persistence in the face of rapid environmental change.
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| 26. |
- Tobler, Michael, et al.
(författare)
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Telomeres in ecology and evolution : A review and classification of hypotheses
- 2022
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 31:23, s. 5946-5965
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Forskningsöversikt (refereegranskat)abstract
- 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 telomeres and life-history traits or fitness-facilitating processes (and the mechanisms underlying them). However, the differences (or similarities) between the various hypotheses, which can originate from different research fields, are often not obvious. Our aim here is therefore to give an overview of the hypotheses that are of interest in ecology and evolution and to provide two frameworks that help discriminate among them. We group the hypotheses (i) based on their association with different research questions, and (ii) using a hierarchical approach that builds on the assumptions they make, such as about causality of telomere length/shortening and/or the proposed functional consequences of telomere shortening on organism performance. Both our frameworks show that there exist parallel lines of thoughts in different research fields. Moreover, they also clearly illustrate that there are in many cases competing hypotheses within clusters, and that some of these even have contradictory assumptions and/or predictions. We also touch upon two topics in telomere research that would benefit from further conceptualization. This review should help researchers, both those familiar with and those new to the subject, to identify future avenues of research.
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| 27. |
- Zhang, Hongkai, et al.
(författare)
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Evidence of Site-Specific and Male-Biased Germline Mutation Rate in a Wild Songbird
- 2023
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Ingår i: Genome Biology and Evolution. - 1759-6653. ; 15:11
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Tidskriftsartikel (refereegranskat)abstract
- 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 widely investigated in most species. To address these gaps, we conducted whole-genome sequencing of 12 great reed warblers (Acrocephalus arundinaceus) in a pedigree spanning 3 generations to identify single-nucleotide de novo mutations (DNMs) and estimate the germline mutation rate. We detected 82 DNMs within the pedigree, primarily enriched at CpG sites but otherwise randomly located along the chromosomes. Furthermore, we observed a pronounced sex bias in DNM occurrence, with male warblers exhibiting three times more mutations than females. After correction for false negatives and adjusting for callable sites, we obtained a mutation rate of 7.16 × 10−9 mutations per site per generation (m/s/g) for the autosomes and 5.10 × 10−9 m/s/g for the Z chromosome. To demonstrate the utility of species-specific mutation rates, we applied our autosomal mutation rate in models reconstructing the demographic history of the great reed warbler. We uncovered signs of drastic population size reductions predating the last glacial period (LGP) and reduced gene flow between western and eastern populations during the LGP. In conclusion, our results provide one of the few direct estimates of the mutation rate in wild songbirds and evidence for male-driven mutations in accordance with theoretical expectations.
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| 28. |
- Åkesson, Mikael, et al.
(författare)
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Estimating heritabilities and genetic correlations: comparing the 'animal model' with parent-offspring regression using data from a natural population.
- 2008
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:3
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Tidskriftsartikel (refereegranskat)abstract
- Quantitative genetic parameters are nowadays more frequently estimated with restricted maximum likelihood using the 'animal model' than with traditional methods such as parent-offspring regressions. These methods have however rarely been evaluated using equivalent data sets. We compare heritabilities and genetic correlations from animal model and parent-offspring analyses, respectively, using data on eight morphological traits in the great reed warbler (Acrocephalus arundinaceus). Animal models were run using either mean trait values or individual repeated measurements to be able to separate between effects of including more extended pedigree information and effects of replicated sampling from the same individuals. We show that the inclusion of more pedigree information by the use of mean traits animal models had limited effect on the standard error and magnitude of heritabilities. In contrast, the use of repeated measures animal model generally had a positive effect on the sampling accuracy and resulted in lower heritabilities; the latter due to lower additive variance and higher phenotypic variance. For most trait combinations, both animal model methods gave genetic correlations that were lower than the parent-offspring estimates, whereas the standard errors were lower only for the mean traits animal model. We conclude that differences in heritabilities between the animal model and parent-offspring regressions were mostly due to the inclusion of individual replicates to the animal model rather than the inclusion of more extended pedigree information. Genetic correlations were, on the other hand, primarily affected by the inclusion of more pedigree information. This study is to our knowledge the most comprehensive empirical evaluation of the performance of the animal model in relation to parent-offspring regressions in a wild population. Our conclusions should be valuable for reconciliation of data obtained in earlier studies as well as for future meta-analyses utilizing estimates from both traditional methods and the animal model.
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