| 1. |
|
|
| 2. |
|
|
| 3. |
- Abbott, J. K., et al.
(författare)
-
Patterns of differentiation in a colour polymorphism and in neutral markers reveal rapid genetic changes in natural damselfly populations
- 2008
-
Ingår i: Molecular Ecology. - : Wiley-Blackwell. - 0962-1083 .- 1365-294X. ; 17:6, s. 1597-1604
-
Tidskriftsartikel (refereegranskat)abstract
- The existence and mode of selection operating on heritable adaptive traits can be inferred by comparing population differentiation in neutral genetic variation between populations (often using F-ST values) with the corresponding estimates for adaptive traits. Such comparisons indicate if selection acts in a diversifying way between populations, in which case differentiation in selected traits is expected to exceed differentiation in neutral markers [F-ST (selected) > F-ST (neutralfl, or if negative frequency-dependent selection maintains genetic polymorphisms and pulls populations towards a common stable equilibrium [FST (selected) < F-ST (neutral)]. Here, we compared F-ST values for putatively neutral data (obtained using amplified fragment length polymorphism) with estimates of differentiation in morph frequencies in the colour-polymorphic damselfly Ischnura elegans. We found that in the first year (2000), population differentiation in morph frequencies was significantly greater than differentiation in neutral loci, while in 2002 (only 2 years and 2 generations later), population differentiation in morph frequencies had decreased to a level significantly lower than differentiation in neutral loci. Genetic drift as an explanation for population differentiation in morph frequencies could thus be rejected in both years. These results indicate that the type and/or strength of selection on morph frequencies in this system can change substantially between years. We suggest that an approach to a common equilibrium morph frequency across all populations, driven by negative frequency-dependent selection, is the cause of these temporal changes. We conclude that inferences about selection obtained by comparing F-ST values from neutral and adaptive genetic variation are most useful when spatial and temporal data are available from several populations and time points and when such information is combined with other ecological sources of data.
|
|
| 4. |
- Andersson, Jesper Emanuel, et al.
(författare)
-
A hybrid population of Willow Warblers in the Åland Archipelago
-
Ingår i: Journal of Ornithology. - 2193-7192.
-
Tidskriftsartikel (refereegranskat)abstract
- Differences in migratory behavior have been suggested to drive speciation, but the genetics underlying this process remain unknown. Identification and study of migratory divides can help us understand how differential migration can lead to reproductive isolation. Here, we genotyped Willow Warblers Phylloscopus trochilus, from the Åland islands, located in between the ranges of the differentially migrating subspecies P. t. trochilus and P. t. acredula. We found that Willow Warblers on the Åland islands were genetically intermediate to allopatric populations of both parental subspecies, providing evidence that the islands constitute a previously unknown hybrid swarm, likely to be a migratory divide.
|
|
| 5. |
- Arlt, D, et al.
(författare)
-
Breeding synchrony does not affect extra-pair paternity in great reed warblers
- 2004
-
Ingår i: Behaviour. - : Brill. - 1568-539X .- 0005-7959. ; 141:7, s. 863-880
-
Tidskriftsartikel (refereegranskat)abstract
- Breeding synchrony is hypothesised to influence the occurrence and frequency of extra-pair fertilisations (EPFs) in birds irrespective of the social mating system. The two proposed hypotheses make opposite predictions. (1) Synchronous breeding leads to a lower frequency of EPFs because males face a trade-off between mate guarding and obtaining additional matings via extra-pair copulations (EPCs) ('guarding constraint' hypothesis). (2) Synchronous breeding promotes EPFs because females are able to compare displaying males simultaneously, which provides them with more reliable cues for extra-pair mate choice ('mate assessment' hypothesis). In a study of great reed warblers (Acrocephalus arundillaceus) from 1987-1998, annual breeding was asynchronous and the frequency of EPFs was rather low (extra-pair young occurring in 6.4% of the broods). Within this population, however, there was no relationship between the frequency of EPFs and breeding synchrony, thus not favouring any of the two hypotheses. Contrary to assumptions of the hypotheses, mate guarding did not seem to constrain males from engaging in EPCs (disfavouring the 'guarding constraint' hypothesis), and females seem to have repeated opportunities to compare males irrespective of breeding synchrony (disfavouring the 'mate assessment' hypothesis). Our results suggest that breeding synchrony is not an important factor influencing patterns of EPFs in great reed warblers. The low frequency of EPFs may instead be explained by the socially polygynous mating system, where females are less constrained in their choice of a social male.
|
|
| 6. |
- Arlt, D, et al.
(författare)
-
Observation of a ZZW female in a natural population: implications for avian sex determination
- 2004
-
Ingår i: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 271:S4, s. 249-251
-
Tidskriftsartikel (refereegranskat)abstract
- Avian sex determination is chromosomal; however, the underlying mechanisms are not yet understood. There is no conclusive evidence for either of two proposed mechanisms: a dominant genetic switch or a dosage mechanism. No dominant sex-determining gene on the female-specific W chromosome has been found. Birds lack inactivation of one of the Z chromosomes in males, but seem to compensate for a double dose of Z-linked genes by other mechanisms. Recent studies showing female-specific expression of two genes may support an active role of the W chromosome. To resolve the question of avian sex determination the investigation of birds with a 2A: ZZW or 2A: Z0 genotype would be decisive. Here, we report the case of an apparent 2A: ZZW great reed warbler (Acrocephalus arundinaceus) female breeding in a natural population, which was detected using Z-linked microsatellites. Our data strongly suggest a role of W-linked genes in avian sex determination.
|
|
| 7. |
- Asghar, Muhammad, et al.
(författare)
-
Parallel telomere shortening in multiple body tissues owing to malaria infection
- 2016
-
Ingår i: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 1471-2954 .- 0962-8452. ; 283:1836
-
Tidskriftsartikel (refereegranskat)abstract
- Several studies have shown associations between shorter telomere length in blood and weakened immune function, susceptibility to infections, and increased risk of morbidity and mortality. Recently, we have shown that malaria accelerates telomere attrition in blood cells and shortens lifespan in birds. However, the impact of infections on telomere attrition in different body tissues within an individual is unknown. Here, we tested whether malarial infection leads to parallel telomere shortening in blood and tissue samples from different organs. We experimentally infected siskins (Spinus spinus) with the avian malaria parasite Plasmodium ashfordi, and used real-time quantitative polymerase chain reaction (PCR) to measure telomere length in control and experimentally infected siskins. We found that experimentally infected birds showed faster telomere attrition in blood over the course of infection compared with control individuals (repeatedly measured over 105 days post-infection (DPI)). Shorter telomeres were also found in the tissue of all six major organs investigated (liver, lungs, spleen, heart, kidney, and brain) in infected birds compared with controls at 105 DPI. To the best of our knowledge, this is the first study showing that an infectious disease results in synchronous telomere shortening in the blood and tissue cells of internal organs within individuals, implying that the infection induces systemic stress. Our results have far-reaching implications for understanding how the short-term effects of an infection can translate into long-term costs, such as organ dysfunction, degenerative diseases, and ageing.
|
|
| 8. |
|
|
| 9. |
- Aželytė, Justė, et al.
(författare)
-
A comparative analysis of the dynamics of Plasmodium relictum (GRW4) development in the blood during single and co-infections
- 2022
-
Ingår i: Acta Tropica. - : Elsevier BV. - 0001-706X. ; 226
-
Tidskriftsartikel (refereegranskat)abstract
- Although co-infections and interactions of parasites are a very common phenomenon in the wild, information received from studies on avian Plasmodium spp. is scarce and fragmented due to its complex nature. Different interactions of parasites and domination of one parasite may have a detrimental effect on transmission success of another pathogen. Untangling these interactions and competitive behavior of malarial parasites may help understanding why some haemosporidian parasites are dominant in certain host species, while others are observed only occasionally. We investigated the development of Plasmodium relictum (genetic lineage GRW4) during single and co-infection with a closely related lineage SGS1, with the aim to determine whether co-infections affect parasite development and condition of experimentally infected Eurasian siskins (Spinus spinus). For the experimental study of these two closely related lineages, a new qPCR protocol was designed to accurately quantify the parasitemia, i.e. the amount of infected red blood cells, during the blood stages of each of the lineages. Our results show that during co-infection, GRW4 parasitemia was transient and disappeared from peripheral blood during acute increases of SGS1. Health parameters of infected birds did not differ between the GRW4 single infected group and the co-infection group. GRW4 induced infection was outcompeted and suppressed by the presence of the lineage SGS1, which is broadly transmitted in Northern Europe. This suggests that double infections and dominating lineages in the area may influence the transmission success of some avian Plasmodium parasites.
|
|
| 10. |
- Beadell, JS, et al.
(författare)
-
Global phylogeographic limits of Hawaii's avian malaria
- 2006
-
Ingår i: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 273:1604, s. 2935-2944
-
Tidskriftsartikel (refereegranskat)abstract
- The introduction of avian malaria (Plasmodium relictum) to Hawaii has provided a model system for studying the influence of exotic disease on naive host populations. Little is known, however, about the origin or the genetic variation of Hawaii's malaria and traditional classification methods have confounded attempts to place the parasite within a global ecological and evolutionary context. Using fragments of the parasite mitochondrial gene cytochrome b and the nuclear gene dihydrofolate reductase-thymidylate synthase obtained from a global survey of greater than 13 000 avian samples, we show that Hawaii's avian malaria, which can cause high mortality and is a major limiting factor for many species of native passerines, represents just one of the numerous lineages composing the morphological parasite species. The single parasite lineage detected in Hawaii exhibits a broad host distribution worldwide and is dominant on several other remote oceanic islands, including Bermuda and Moorea, French Polynesia. The rarity of this lineage in the continental New World and the restriction of closely related lineages to the Old World suggest limitations to the transmission of reproductively isolated parasite groups within the morphological species.
|
|
| 11. |
|
|
| 12. |
- Bensch, Staffan, et al.
(författare)
-
Amplified fragment length polymorphism analysis identifies hybrids between two subspecies of warblers.
- 2002
-
Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 11:3, s. 473-481
-
Tidskriftsartikel (refereegranskat)abstract
- In the western Pyrenees (Southwest France and Northwest Spain), a narrow hybrid zone exists between the common chiffchaff Phylloscopus (collybita) collybita and the Iberian chiffchaff Phylloscopus (c.) brehmii. In this zone, which is approximately 20 km wide, mixed matings and individuals singing the songs of both taxa occur at substantial frequencies (24 and 8.6%, respectively), suggesting frequent hybridization. Previous studies have shown very weak mitochondrial gene flow (Nm = 0.065), whereas four microsatellites suggested much higher nuclear gene flow (Nm = 4.9). In this study we used the amplified fragment length polymorphism (AFLP) method in order to identify hybrids and early backcrosses. We typed 91 birds from both allopatric and sympatric areas for 12 informative AFLP markers (of > 141 polymorphic fragments), obtained by screening 13 AFLP primer combinations. These individuals were previously typed for song (brehmii, collybita or mixed singers), mitochondrial DNA (mtDNA) haplotype and allelic genotypes at four microsatellite loci. Assignment tests demonstrated that in the zone of sympatry, a substantial number of intermediate genotypes existed among the birds previously believed to be pure collybita and brehmii, based on song and mtDNA haplotype. The majority of the mixed singers had intermediate genotypes. Our data suggest that the fraction of the adult population having a hybrid origin (hybrids or backcrosses) is in the order of 10%. With such a frequency of genetic hybrids, there would have been much more mtDNA introgression than observed, had female hybrids been perfectly fertile/viable. This result is consistent with male-biased gene flow and Haldane's rule.
|
|
| 13. |
- Bensch, Staffan, et al.
(författare)
-
Brain parasites and misorientation of migratory birds
-
Ingår i: Trends in Parasitology. - 1471-4922.
-
Tidskriftsartikel (refereegranskat)abstract
- Haemoproteus blood parasites of birds are thought to be relatively benign. Recent findings show that infections may develop in the brain of birds, possibly distorting their orientation sense. Misdirected migration may lead migrants outside their range where they are recognized as vagrants and can transmit parasites to novel hosts.
|
|
| 14. |
- Bensch, Staffan, et al.
(författare)
-
Conflicting patterns of mitochondrial and nuclear DNA diversity in Phylloscopus warblers
- 2006
-
Ingår i: Molecular Ecology. - 0962-1083. ; 15:1, s. 161-171
-
Tidskriftsartikel (refereegranskat)abstract
- Molecular variation is often used to infer the demographic history of species, but sometimes the complexity of species history can make such inference difficult. The willow warbler, Phylloscopus trochilus, shows substantially less geographical variation than the chiffchaff, Phylloscopus collybita, both in morphology and in mitochondrial DNA (mtDNA) divergence. We therefore predicted that the willow warbler should harbour less nuclear DNA diversity than the chiffchaff. We analysed sequence data obtained from multiple samples of willow warblers and chiffchaffs for the mtDNA cytochrome b gene and four nuclear genes. We confirmed that the mtDNA diversity among willow warblers is low (π = 0.0021). Sequence data from three nuclear genes (CHD-Z, AFLP-WW1 and MC1R) not linked to the mitochondria demonstrated unexpectedly high nucleotide diversity (π values of 0.0172, 0.0141 and 0.0038) in the willow warbler, on average higher than the nucleotide diversity for the chiffchaff (π values of 0.0025, 0.0017 and 0.0139). In willow warblers, Tajima's D analyses showed that the mtDNA diversity, but not the nuclear DNA diversity, has been reduced relative to the neutral expectation of molecular evolution, suggesting the action of a selective sweep affecting the maternally inherited genes. The large nuclear diversity seen within willow warblers is not compatible with processes of neutral evolution occurring in a population with a constant population size, unless the long-term effective population size has been very large (Ne > 106). We suggest that the contrasting patterns of genetic diversity in the willow warbler may reflect a more complex evolutionary history, possibly including historical demographic fluctuations or historical male-biased introgression of nuclear genes from a differentiated population of Phylloscopus warblers.
|
|
| 15. |
- Bensch, Staffan, et al.
(författare)
-
Contaminations contaminate common databases
- 2021
-
Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; 21:2, s. 355-362
-
Tidskriftsartikel (refereegranskat)abstract
- The polymerase chain reaction (PCR) is a very powerful method to detect and identify pathogens. The high sensitivity of the method, however, comes with a cost; any of the millions of artificial DNA copies generated by PCR can serve as a template in a following experiment. If not identified as contaminations, these may result in erroneous conclusions on the occurrence of the pathogen, thereby inflating estimates of host range and geographic distribution. In the present paper, we evaluate whether several published records of avian haemosporidian parasites, in either unusual host species or geographical regions, might stem from PCR contaminations rather than novel biological findings. The detailed descriptions of these cases are shedding light upon the steps in the work process that might lead to PCR contaminations. By increasing the awareness of this problem, it will aid in developing procedures that keep these to a minimum. The examples in the present paper are from haemosporidians of birds, however the problem of contaminations and suggested actions should apply generally to all kinds of PCR-based identifications, not just of parasites and pathogens.
|
|
| 16. |
- Bensch, Staffan
(författare)
-
Female mating status and reproductive success in the great reed warbler: Is there a potential cost of polygyny that requires compensation?
- 1996
-
Ingår i: Journal of Animal Ecology. - 1365-2656. ; 65:3, s. 283-296
-
Tidskriftsartikel (refereegranskat)abstract
- 1. Using data from a 9-year study of the great reed warbler Acrocephalus arundinaceus L. carried out in Sweden, I tested the main assumption of the polygyny threshold model (that there is a cost of polygyny) and the main prediction (that this cost is compensated for). The main question was whether a female that chose a mated male (secondary females) experienced the same fitness as a female that at the same time chose an unmated male (primary females). The study includes a total of 192 breeding seasons of 104 individual females of which 40% settled with already mated males. 2. Eight potential correlates of fitness were examined; namely, clutch size, hatching success, hedging success, survival until breeding age, nest survival, mass of fledglings, mass of feeding females and annual survival rate of breeding females. I started each analysis by controlling for four potential confounding variables (year, study site, female age and breeding date). Then I compared the average fitness measure of primary and secondary females. 3. The only detected potential component cost of polygyny was a higher mortality among nestlings if a non-primary position within the harem was retained until hatching. This was supported by a natural experiment. Females that initially chose mated males but which achieved a primary position after failure of the originally primary female's nest enjoyed an increased fledging success, probably because of more male assistance. 4. The number of recruits, controlling for settling dates, for the two categories of females were almost identical (primary females 0 . 53 recruits per year, secondary females 0 . 51 recruits per year). Since secondary and primary females showed similar rates of survival until next breeding season the fitness of the two strategies appears to be equal. These findings strongly suggest that polygyny in the great reed warbler is best explained by the compensation models such as the polygyny threshold model.
|
|
| 17. |
|
|
| 18. |
- Bensch, Staffan, et al.
(författare)
-
Genetic, morphological, and feather isotope variation of migratory willow warblers show gradual divergence in a ring.
- 2009
-
Ingår i: Molecular Ecology. - 0962-1083 .- 1365-294X. ; 18:14, s. 3087-96
-
Tidskriftsartikel (refereegranskat)abstract
- The circular distribution of the willow warbler Phylloscopus trochilus around the Baltic Sea shares many features with the classic examples of ring species; however, the system is much younger. It has previously been shown that a secondary contact zone is located in central Scandinavia, where there are narrow clines for several morphological traits coincident with a migratory divide. Here we analyse multiple traits and genes from > 1700 males captured on breeding territories at 77 sites spread around the Baltic Sea to test the following hypothesis. If the secondary contact zone in Scandinavia is a result of divergence in two allopatric refuge populations during the last glaciation, we expect to find a similar secondary contact zone somewhere else around the circular distribution. Our results show that the trait clines were wider and displaced from each other along the eastern side of the Baltic Sea. Analyses of 12 microsatellite loci confirmed that the genome is very similar between the terminal forms (F(ST) = 0). Two AFLP-derived markers filtered out from a genomic scan instead appear to be maintained by selection. These markers exhibited steep clines at the secondary contact zone in Scandinavia, but as for the phenotypic traits, had vastly different cline centres east of the Baltic Sea. The trait clines along the ring distribution outside the Scandinavian secondary contact zone thus seem to have been shaped by independent action of selection or drift during the process of postglacial colonization.
|
|
| 19. |
- Bensch, Staffan, et al.
(författare)
-
Genomic Resources Notes accepted 1 June 2013-31 July 2013
- 2014
-
Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X. ; 14:1, s. 218-218
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This article documents the public availability of (i) raw transcriptome sequence data, assembled contigs and UniProt BLAST hits from common crossbill (Loxia curvirostra) and Plasmodium relictum (lineage SGS1) obtained from a controlled infection experiment; and (ii) raw transcriptome sequence data and 66596 SNPs for the white-tailed deer (Odocoileus virginianus).
|
|
| 20. |
- Bensch, Staffan, et al.
(författare)
-
Geolocator tagging of east Siberian Bluethroats
- 2022
-
Ingår i: Journal of Ornithology. - : Springer Science and Business Media LLC. - 2193-7192 .- 2193-7206. ; 163:3, s. 843-847
-
Tidskriftsartikel (refereegranskat)abstract
- The Bluethroat subspecies Cyanecula svecica svecia occurs throughout the northern Palearctic. European C. s. svecia has been shown to follow a route west of the Himalaya to winter quarters in southern Asia. Out of 30 Bluethroats tagged with geolocators in eastern Siberia, we obtained one track suggesting that it migrated east of the Himalaya to a wintering area located in Myanmar. The different routes of western and eastern C. s. svecia implicate the presence of a migratory divide in Siberia, either formed in situ during the post-glacial colonization process or resulting from a secondary contact between different refuge populations.
|
|
| 21. |
- Bensch, Staffan, et al.
(författare)
-
Host specificity in avian blood parasites: a study of Plasmodium and Haemoproteus mitochondrial DNA amplified from birds
- 2000
-
Ingår i: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 267:1452, s. 1583-1589
-
Tidskriftsartikel (refereegranskat)abstract
- A fragment of the mitochondrial cytochrome b gene of avian malaria (genera Haemoproteus and Plasmodium) was amplified from blood samples of 12 species of passerine birds from the genera Acrocephalus, Phylloscopus and Parus. By sequencing 478 nucleotides of the obtained fragments, we found 17 different mitocholdrial haplotypes of Haemoproteus or Plasmodium among the 12 bird species investigated. Only one out of the: 17 haplotypes was found in more than one host species, this exception being a haplotype detected in both blue tits (Parus caeruleus) and great tits (Parus major). The phylogenetic tree which was constructed grouped the sequences into two clades, most probably representing Haemoproteus and Plasmodium, respectively. We found two to four different parasite mitochondrial DNA (mtDNA) haplotypes in four bird species. The phylogenetic tree obtained from the mtDNA of the parasites matched the phylogenetic tree of the bird hosts poorly For example, the two tit species and the willow warbler (Phylloscopus troclilus) carried parasites differing by only 0.6% sequence divergence, suggesting that Haemoproteus shift both between species within the same genus and also between species in different families. Hence, host shifts seem to have occurred repeatedly in this parasite-host system. We discuss this in terms of the possilble evolutionary consequences for these bird species.
|
|
| 22. |
- Bensch, Staffan, et al.
(författare)
-
How can we determine the molecular clock of malaria parasites?
- 2013
-
Ingår i: Trends in Parasitology. - : Elsevier BV. - 1471-5007 .- 1471-4922. ; 29:8, s. 363-369
-
Forskningsöversikt (refereegranskat)abstract
- The association of contemporary hosts and their parasites might reflect either cospeciation or more recent shifts among existing hosts. Cospeciation implies that lineages of hosts and parasites diverge in parallel at the same time, but testing this prediction requires time-calibrated phylogenies, which are particularly difficult to obtain in organisms that leave few fossils. It has successively become clear that host shifts have been frequent in the evolutionary history of malaria parasites, but dating these host shifts cannot be done without calibrated phylogenies. Hence, it remains unresolved how long contemporary hosts and vectors have been coevolving with their malaria parasites. This review addresses conflicting rate estimates of molecular evolution and suggests research directions to aid dating diversification events in malaria parasites.
|
|
| 23. |
|
|
| 24. |
- Bensch, Staffan, et al.
(författare)
-
Linkage between nuclear and mitochondrial DNA sequences in avian malaria parasites: Multiple cases of cryptic speciation?
- 2004
-
Ingår i: Evolution. - : Wiley. - 1558-5646 .- 0014-3820. ; 58:7, s. 1617-1621
-
Tidskriftsartikel (refereegranskat)abstract
- Analyses of mitochondrial cytochrome b diversity among avian blood parasites of the genera Haemoproteus and Plasmodium suggest that there might be as many lineages of parasites as there are species of birds. This is in sharp contrast to the approximately 175 parasite species described by traditional methods based on morphology using light microscopy. Until now it has not been clear to what extent parasite mitochondrial DNA lineage diversity reflects intra- or interspecific variation. We have sequenced part of a fast-evolving nuclear gene, dihydrofolate reductase-thymidylate synthase (DHFR-TS), and demonstrate that most of the parasite mitochondrial DNA lineages are associated with unique gene copies at this locus. Although these parasite lineages sometimes coexist in the same host individual, they apparently do not recombine and could therefore be considered as functionally distinct evolutionary entities, with independent evolutionary potential. Studies examining parasite virulence and host immune systems must consider this remarkable diversity of avian malaria parasites.
|
|
| 25. |
- Bensch, Staffan, et al.
(författare)
-
Low prevalence of Haemoproteus infections in Chiffchaffs.
- 2012
-
Ingår i: Parasitology. - 1469-8161. ; 139, s. 302-309
-
Tidskriftsartikel (refereegranskat)abstract
- SUMMARY: Parasite prevalence is an important variable in many evolutionary and ecological studies. In birds, haemosporidian blood parasites have been in focus of many comparative analyses. Because low prevalence is difficult to estimate precisely and that studies finding low prevalence are more likely to remain unpublished, our knowledge of parasite prevalence is biased towards highly infected taxa. Species with naturally low levels of infection are nonetheless interesting as they may provide models for studying the evolution of pathogen resistance. In the present study we show that the prevalence of Haemoproteus parasites is markedly lower in several taxa within the widely distributed chiffchaff species-complex compared to other species within the genus Phylloscopus. Since chiffchaffs, P. collybita, commonly coexists in the same habitat as congeners frequently infected with Haemoproteus parasites, immediate ecological variables like abundance of vectors can hardly explain this difference. Some of the parasites infecting coexisting congeners are broad host generalists leaving it enigmatic why chiffchaffs are almost free of Haemoproteus infections. We propose that detailed infection experiments are needed to illuminate whether chiffchaffs possess a genetic immunity against Haemoproteus parasites or if other more subtle ecological processes, like anti-vector behaviour, play a role in its generally low level of infestation.
|
|
| 26. |
- Bensch, Staffan, et al.
(författare)
-
MalAvi : A public database of malaria parasites and related haemosporidians in avian hosts based on mitochondrial cytochrome b lineages
- 2009
-
Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; 9:5, s. 1353-1358
-
Tidskriftsartikel (refereegranskat)abstract
- Research in avian blood parasites has seen a remarkable increase since the introduction of polymerase chain reaction-based methods for parasite identification. New data are revealing complex multihost-multiparasite systems which are difficult to understand without good knowledge of the host range and geographical distribution of the parasite lineages. However, such information is currently difficult to obtain from the literature, or from general repositories such as GenBank, mainly because (i) different research groups use different parasite lineage names, (ii) GenBank entries frequently refer only to the first host and locality at which each parasite was sampled, and (iii) different researchers use different gene fragments to identify parasite lineages. We propose a unified database of avian blood parasites of the genera Plasmodium, Haemoproteus and Leucocytozoon identified by a partial region of their cytochrome b sequences. The database uses a standardized nomenclature to remove synonymy, and concentrates all available information about each parasite in a public reference site, thereby facilitating access to all researchers. Initial data include a list of host species and localities, as well as genetic markers that can be used for phylogenetical analyses. The database is free to download and will be regularly updated by the authors. Prior to publication of new lineages, we encourage researchers to assign names to match the existing database. We anticipate that the value of the database as a source for determining host range and geographical distribution of the parasites will grow with its size and substantially enhance the understanding of this remarkably diverse group of parasites.
|
|
| 27. |
- Bensch, Staffan, et al.
(författare)
-
Mitochondrial genomic rearrangements in songbirds
- 2000
-
Ingår i: Molecular biology and evolution. - 0737-4038. ; 17:1, s. 107-113
-
Tidskriftsartikel (refereegranskat)abstract
- The organization of the mitochondrial genome is generally very conserved among vertebrates. Because of this, examination of the rare rearrangements which do occur has been suggested as offering a powerful alternative to phylogenetic analyses of mitochondrial DNA sequences. Here, we report on an avian mitochondrial rearrangement in a group of oscine passerines (warblers of the genus Phylloscopus). This rearrangement is identical to the mitochondrial organization recently identified in representatives of four orders of birds, including subsoscine Passeriformes. The rearrangement involves the movement of three genes (tRNA(Pro), NADH6, and rRNA(Glu)) from their normal position in birds between tRNA(Thr) and the control region (CR), to a new location between the CR and a novel, supposedly noncoding (NC), region. Our results suggest that this derived arrangement cannot be used to distinguish between suboscine and oscine passerines, as it has multiple origins both within Passeriformes and within birds as a whole. We found short stretches of DNA with high degrees of similarity between the CR and each NC region, respectively, all of which could be located in the same area of the CR. This suggests that the CR and the NC region are homologous and that the mechanism behind this mitochondrial rearrangement is a tandem duplication followed by multiple deletions. However, the similarities between the control and NC regions of each species were less pronounced than those between the control or NC regions from the different species, supporting the hypothesis of a single basal rearrangement in the Phylloscopus warblers.
|
|
| 28. |
- Bensch, Staffan, et al.
(författare)
-
Partial albinism in a semi-isolated population of great reed warblers
- 2000
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 1601-5223 .- 0018-0661. ; 133:2, s. 167-170
-
Tidskriftsartikel (refereegranskat)abstract
- Albinism in birds is thought to result from the expression of recessive alleles that disrupt melanin pigmentation at feather development. We have studied great reed warblers Acrocephalus arundinaceus in a recently founded and increasing population in Sweden during 15 years for the presence of birds with albinistic feathers. The study population was founded in 1978 and the few cases of albinism was exclusively recorded during the first five pears of our study (1985-1989). This fits to the expected pattern if albinism is governed by recessive alleles; we have previously demonstrated that the population suffered from inbreeding during the first years of our study. The albinistic birds experienced a similar lifetime reproductive success as normally coloured birds.
|
|
| 29. |
- Bensch, Staffan, et al.
(författare)
-
Patterns of stable isotope signatures in willow warbler Phylloscopus trochilus feathers collected in Africa
- 2006
-
Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857. ; 37:4, s. 323-330
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We conducted stable isotope analyses of nitrogen and carbon on feathers obtained from willow warblers in Africa to find an explanation for a previously observed pattern of different delta N-15 and delta C-13 values across a migratory divide in central Scandinavia. A new data set confirms that north Scandinavian birds of the subspecies P. t. acredula have higher delta N-15 values than south Scandinavian birds of the subspecies P. t. trochilus. In Africa, we found significant differences for both delta N-15 and delta C-13 values among feathers collected from major geographical regions as well as between countries within regions. Isotope signatures of delta N-15 and delta C-13 in Scandinavian acredula matched well with those of willow warblers sampled in southern parts of Africa, but differed from samples obtained in East and West Africa. Isotope signatures in Scandinavian trochilus did not agree with the pattern in any of the three African regions (West, East or South). However, a more detailed analysis of the isotopic data in feathers from countries within West Africa, which is the wintering region of Swedish trochilus based on ringing recoveries, revealed a correspondence with samples from Liberia, the Ivory Coast and Nigeria.
|
|
| 30. |
|
|
| 31. |
- Bensch, Staffan, et al.
(författare)
-
Selection for Heterozygosity Gives Hope to a Wild Population of Inbred Wolves
- 2006
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 1:1
-
Tidskriftsartikel (refereegranskat)abstract
- Recent analyses have questioned the usefulness of heterozygosity estimates as measures of the inbreeding coefficient (f ), a finding that may have dramatic consequences for the management of endangered populations. We confirm that f and heterozygosity is poorly correlated in a wild and highly inbred wolf population. Yet, our data show that for each level of f, it was the most heterozygous wolves that established themselves as breeders, a selection process that seems to have decelerated the loss of heterozygosity in the population despite a steady increase of f. The markers contributing to the positive relationship between heterozygosity and breeding success were found to be located on different chromosomes, but there was a substantial amount of linkage disequilibrium in the population, indicating that the markers are reflecting heterozygosity over relatively wide genomic regions. Following our results we recommend that management programs of endangered populations include estimates of both f and heterozygosity, as they may contribute with complementary information about population viability.
|
|
| 32. |
- Bensch, Staffan, et al.
(författare)
-
Temporal and spatial variation of hematozoans in Scandinavian willow warblers
- 2003
-
Ingår i: The Journal of Parasitology. - 0022-3395. ; 89:2, s. 388-391
-
Tidskriftsartikel (refereegranskat)abstract
- We examined temporal and geographical distribution of Haemoproteus sp. and Plasmodium sp. parasites in Swedish willow warblers, Phylloscopus trochilus. Parasite lineages were detected with molecular methods in 556 birds from 41 sites distributed at distances up to 1,500 km. Two mitochondrial lineages of Haemoproteus sp. were detected, WW1 in 56 birds and WW2 in 75 birds, that differed by 5.2% sequence divergence. We discuss the reasons behind the observed pattern of variation and identify 3 possible causes: (1) variation in the geographic distribution of the vector species, (2) the degree of parasite sharing with other bird species coexisting with the willow warbler, and (3) timing of transmission. Our results support a fundamental and rarely tested assumption of the now classical Hamilton-Zuk hypothesis of sexual selection, namely, that these parasites vary in both time and space. Such fluctuations of parasites and the selection pressure they Supposedly impose on the host population are likely to maintain variation in immune system genes in the host population.
|
|
| 33. |
|
|
| 34. |
- Bensch, Staffan, et al.
(författare)
-
Temporal dynamics and diversity of avian malaria parasites in a single host species
- 2007
-
Ingår i: Journal of Animal Ecology. - : Wiley. - 1365-2656 .- 0021-8790. ; 76:1, s. 112-122
-
Tidskriftsartikel (refereegranskat)abstract
- We have used molecular methods to unravel a remarkable diversity of parasite lineages in a long-term population study of great reed warblers Acrocephalus arundinaceus that was not foreseen from traditional microscopic examination of blood smears. This diversity includes eight Haemoproteus and 10 Plasmodium lineages of which most probably represent good biological species.Contrary to expectation, the relative frequency of parasite lineages seemed not to change over the 17-year study period and we found no effects of the parasites on a male secondary sexual ornament (song repertoire size) and two measures of fitness (adult survival and production of recruited offspring).We discuss whether the absence of fitness consequences of the parasites might relate to the fact that we have studied the host at the breeding sites in Europe, whereas the transmission seems to take place at the wintering sites in Africa, where the naive birds encounter the parasites for the first time and the resulting primary infections likely make them sicker than during the chronic phase of the infection.The prevalence of the three most common lineages appeared to fluctuate in parallel with a periodicity of approximately 3-4 years. Theoretical models based on intrinsic interactions between parasite antigen and host immune genes cannot explain such dynamics, suggesting that knowledge of extrinsic parameters such as vector distribution and alternative hosts are required to understand these patterns.
|
|
| 35. |
- Bensch, Staffan, et al.
(författare)
-
Ten years of AFLP in ecology and evolution: why so few animals?
- 2005
-
Ingår i: Molecular Ecology. - 0962-1083. ; 14:10, s. 2899-2914
-
Forskningsöversikt (refereegranskat)abstract
- Researchers in the field of molecular ecology and evolution require versatile and low-cost genetic typing methods. The AFLP (amplified fragment length polymorphism) method was introduced 10 years ago and shows many features that fulfil these requirements. With good quality genomic DNA at hand, it is relatively easy to generate anonymous multilocus DNA profiles in most species and the start-up time before data can be generated is often less than a week. Built-in dynamic, yet simple modifications make it possible to find a protocol suitable to the genome size of the species and to screen thousands of loci in hundreds of individuals for a relatively low cost. Until now, the method has primarily been applied in studies of plants, bacteria and fungi, with a strong bias towards economically important cultivated species and their pests. In this review we identify a number of research areas in the study of wild species of animals where the AFLP method, presently very much underused, should be a very valuable tool. These aspects include classical problems such as studies of population genetic structure and phylogenetic reconstructions, and also new challenges such as finding markers for genes governing adaptations in wild populations and modifications of the protocol that makes it possible to measure expression variation of multiple genes (cDNA-AFLP) and the distribution of DNA methylation. We hope this review will help molecular ecologists to identify when AFLP is likely to be superior to other more established methods, such as microsatellites, SNP (single nucleotide polymorphism) analyses and multigene DNA sequencing.
|
|
| 36. |
- Bensch, Staffan
(författare)
-
The cost of polygyny - definitions and applications
- 1997
-
Ingår i: Journal of Avian Biology. - 0908-8857. ; 28:4, s. 345-352
-
Tidskriftsartikel (refereegranskat)abstract
- The polygyny threshold model was introduced in the 1960s in order to explain why females in some species choose to mate vith already mated males. Since then, a number of complementary or alternative hypotheses have been suggested. By using a hierarchical testing approach Searcy and Yasukawa (1989) organised the models that proposed to explain the maintenance of territorial polygyny. Here, I point out that there is no true way to organise the models, and that the organisation itself may influence which explanation the observations mill support. In particular, I discuss Searcy and Yasukawa's distinction between cost and no-cost models. As an alternative to the hierarchical approach I suggest careful comparisons of those variables that inflict costs of sharing with those that provide compensation. While the hierarchical approach may put very similar systems in different model families, a cost and benefit evaluation might instead show that the difference is quantitative rather than qualitative. Also, an identical cost of polygyny can arise from several different combinations of costs of sharing and benefits of sharing. Hence, the hierarchical approach may put systems with different mechanisms behind polygyny into the same model family.
|
|
| 37. |
- Bensch, Staffan, et al.
(författare)
-
The evolutionary history of “suboptimal” migration routes
- 2023
-
Ingår i: iScience. - 2589-0042. ; 26:11
-
Tidskriftsartikel (refereegranskat)abstract
- Migratoriness in birds is evolutionary labile, with many examples of increasing or decreasing migration distances on the timescale of modern ornithology. In contrast, shifts of migration to more nearby wintering grounds seem to be a slow process. We examine the history of how Palearctic migratory landbirds have expanded their wintering ranges to include both tropical Africa and Asia, a process that has involved major shifts in migratory routes. We found that species with shorter migration distances and with resident populations in the Palearctic more often winter in both Africa and Asia. Our results suggest that changes in wintering grounds are not by long-distance migrant populations per se, but through historic intermediate populations that were less migratory from which long-distance migration evolved secondarily. The failure of long-distance migrants to shift migration direction to more nearby winter quarters indicates that major modifications to the migratory program may be difficult to evolve.
|
|
| 38. |
- Bensch, Staffan, et al.
(författare)
-
The genome of Haemoproteus tartakovskyi and its relationship to human malaria parasites
- 2016
-
Ingår i: Genome Biology and Evolution. - : Oxford University Press (OUP). - 1759-6653. ; 8:5, s. 73-1361
-
Tidskriftsartikel (refereegranskat)abstract
- The phylogenetic relationships among hemosporidian parasites, including the origin of Plasmodium falciparum, the most virulent malaria parasite of humans, have been heavily debated for decades. Studies based on multiple-gene sequences have helped settle many of these controversial phylogenetic issues. However, denser taxon sampling and genome-wide analyses are needed to confidently resolve the evolutionay relationships among hemosporidian parasites. Genome sequences of several Plasmodium parasites are available but only for species infecting primates and rodents. To root the phylogenetic tree of Plasmodium, genomic data from related parasites of birds or reptiles are required. Here, we use a novel approach to isolate parasite DNA from microgametes and describe the first genome of a bird parasite in the sister genus to Plasmodium, Haemoproteus tartakovskyi Similar to Plasmodium parasites, H. tartakovskyi has a small genome (23.2 Mb, 5,990 genes) and a GC content (25.4%) closer to P. falciparum (19.3%) than to Plasmodium vivax (42.3%). Combined with novel transcriptome sequences of the bird parasite Plasmodium ashfordi, our phylogenomic analyses of 1,302 orthologous genes demonstrate that mammalian-infecting malaria parasites are monophyletic, thus rejecting the repeatedly proposed hypothesis that the ancestor of Laverania parasites originated from a secondary host shift from birds to humans. Genes and genomic features previously found to be shared between P. falciparum and bird malaria parasites, but absent in other mammal malaria parasites, are therefore signatures of maintained ancestral states. We foresee that the genome of H. tartakovskyi will open new directions for comparative evolutionary analyses of malarial adaptive traits.
|
|
| 39. |
- Bensch, Staffan, et al.
(författare)
-
The Large-billed Reed Warbler Acrocephalus orinus revisited
- 2002
-
Ingår i: Ibis. - 0019-1019. ; 144:2, s. 259-267
-
Tidskriftsartikel (refereegranskat)abstract
- The Large-billed Reed Warbler Acrocephalus orinus is known only from the type specimen, collected in Himachal Pradesh, India, in 1867. The specimen is poorly prepared, and it has been suggested that it could represent an isolated form of the Clamorous Reed Warbler A. stentoreus or an aberrant Blyth's Reed Warbler A. dumetorum. We tested the affinity of A. orinus by (1) re-examining the morphology of the type specimen and (2) amplifying and sequencing a portion of its mitochondrial cytochrome b gene. Both the morphological and the mitochondrial analyses showed the specimen to be similar to dumetorum, but distinct enough to qualify as a species of its own. Relative to dumetorum, it has a more rounded wing, longer bill, longer and more graduated tail with more pointed tail feathers, and larger claws. The divergence in mitochondrial DNA between orinus and dumetorum was 7.8%, well above the value expected between subspecies. A. orinus is smaller than any of the forms of A. stentoreus or the related Australian Reed Warbler A. australis. It has a somewhat longer first primary, more pointed tail feathers and paler, less robust feet and claws. DNA comparison places it in the clade of small unstreaked Acrocephalus warblers, and apart from the clade of large unstreaked warblers that contains stentoreus and australis.
|
|
| 40. |
- Bensch, Staffan, et al.
(författare)
-
The use of AFLP to find an informative SNP: genetic differences across a migratory divide in willow warblers
- 2002
-
Ingår i: Molecular Ecology. - 0962-1083. ; 11:11, s. 2359-2366
-
Tidskriftsartikel (refereegranskat)abstract
- We used the amplified fragment length polymorphism (AFLP) method to obtain genetic markers distinguishing two subspecies of willow warblers Phylloscopus trochilus that have different migratory behaviours but are not differentiated in mitochondrial DNA or at several microsatellite loci. With the inverse-polymerase chain reaction (PCR) approach we converted a dominant AFLP-marker to a codominant single nucleotide polymorphism (SNP). Across Scandinavia we typed 621 birds at the SNP locus AFLP-WW1 and we found a sigmoid change in allele frequencies centred around 62 degrees latitude. North of the latitudinal cline was a west-east cline. Both clines are narrower than one would expect from dispersal distances in willow warblers, which suggests that these are maintained by selection. The latitudinal cline at the locus AFLP-WW1 is paralleled by changes in several other traits, all of which might be maintained by a single selective force. The most plausible selection factor that we have identified is selection against hybrids because of inferior migratory behaviour. The selective force maintaining the east-west cline is less obvious. We discuss alternatives to the selection scenario, involving colonization history and asymmetric gene flow.
|
|
| 41. |
- Bensch, Staffan, et al.
(författare)
-
The use of molecular methods in studies of avian haemosporidians
- 2020
-
Ingår i: Avian Malaria and Related Parasites in the Tropics : Ecology, Evolution and Systematics - Ecology, Evolution and Systematics. - Cham : Springer International Publishing. - 9783030516338 - 9783030516321 ; , s. 113-135
-
Bokkapitel (refereegranskat)abstract
- During the last two decades, molecular methods to study mitochondrial DNA sequence variation have become an important part in the studies of avian haemosporidians. Up until recently, these methods have primarily been used for identification of the parasites and for tentative phylogenetic reconstructions, allowing researchers not trained in traditional parasitology to compare data across the globe. However, with the introduction of genome and transcriptome sequencing, studies are emerging that go deeper into the genetics and molecular biology of the parasites. In this chapter, we describe and summarize the common methods used for genetic barcoding of the parasites and give an introduction of what to take into account when designing a molecular study of avian haemosporidians. This chapter further discusses why nuclear genetic data are needed in order to answer several important ecological and evolutionary questions and which methods to use in order to overcome the obstacles of obtaining nuclear data of the parasites. Finally, this chapter highlights the challenges and opportunities that come with the use of molecular methods, such as how to study and interpret prevalence, the challenge of aborted developments, and how to obtain data for more robust phylogenies and population structure studies of the parasites.
|
|
| 42. |
- Bobeva, Aneliya, et al.
(författare)
-
A survey of biting midges of the genus Culicoides Latreille, 1809 (Diptera: Ceratopogonidae) in NE Bulgaria, with respect to transmission of avian haemosporidians
- 2013
-
Ingår i: Acta Parasitologica. - : Walter de Gruyter GmbH. - 1230-2821 .- 1896-1851. ; 58:4, s. 585-591
-
Tidskriftsartikel (refereegranskat)abstract
- This study presents data from a molecular survey of the species of the genus Culicoides from the region of Kalimok Field Station (NE Bulgaria) and haemosporidian parasites occurring in them in order to investigate the host-parasite specificity of haemosporidians to their dipteran vectors. The identification of Culicoides spp. was carried out by morphological and molecular-genetic methods. We collected and analysed 230 individuals of the genus Culicoides. Nine species were found. Eight species were identified morphologically; Culicoides obsoletus, C. riethi, C. newsteadi, C. circumscriptus, C. festivipennis, C. punctatus, C. pictipennis and C. puncticollis. The ninth species might be classified as either of C. nubeculosus or C. riethi and its identification needs additional investigations. The total prevalence of Haemoproteus in the examined biting midges was 2.17%. Three individuals of C. pictipennis were infected with the Haemoproteus lineage TURDUS2 (prevalence 16.67%), a common parasite of thrushes (Turdidae). Two individuals of C. circumscriptus contained Haemoproteus lineages (prevalence 2.78%); these were the lineage HAWF2 (previously reported from Coccothraustes coccothraustes) and a new lineage CULCIR1 not previously reported in the literature.
|
|
| 43. |
- Bobeva, A., et al.
(författare)
-
Host preferences of ornithophilic biting midges of the genus Culicoides in the Eastern Balkans
- 2015
-
Ingår i: Medical and Veterinary Entomology. - : Wiley. - 0269-283X. ; 29:3, s. 290-296
-
Tidskriftsartikel (refereegranskat)abstract
- Many biting midges of the genus CulicoidesLatreille, 1809 (Diptera: Ceratopogonidae) are competent vectors of a diverse number of pathogens. The identification of their feeding behaviour and of vector-host associations is essential for understanding their transmission capacity. By applying two different nested polymerase chain reaction (PCR) assays, of which one targeted the avian cyt b gene and the other targeted the COI gene of a wide range of vertebrates, we identified the blood hosts of six biting midge species including Culicoides circumscriptus, Culicoides festivipennis, Culicoides punctatus, Culicoides pictipennis, Culicoides alazanicus and Culicoides cf. griseidorsum, the latter two of which are reported in Bulgaria for the first time. Bird DNA was found in 50.6% of 95 investigated bloodmeals, whereas mammalian DNA was identified in 13.7%. Two Culicoides species were found to feed on both birds and mammals. There was remarkable diversity in the range of avian hosts: 23 species from four orders were identified in the abdomens of four Culicoides species. The most common bird species identified was the magpie, Pica pica (n=7), which was registered in all four ornithophilic biting midge species. Six bloodmeals from the great tit, Parus major, were recorded only in C.alazanicus. None of the studied species of Culicoides appeared to be restricted to a single avian host.
|
|
| 44. |
- Borge, Thomas, 1973-
(författare)
-
Genetics and the Origin of Two Flycatcher Species
- 2004
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, different genetic tools are used to investigate pre- and postzygotic barriers to gene exchange and their role in speciation in the pied flycatcher (Ficedula hypoleuca) and the collared flycatcher (F. albicollis). This species complex consists of four genetically distinct clades that apparently diverged in allopatry (I). Sequencing of introns from autosomal and Z-linked genes from the two species reveals signs of selection on the Z-chromosome. Sexual selection acting on Z-linked genes might explain this pattern (II). By using large-scale genotyping of single nucleotide polymorphisms (SNPs), introgression is observed at autosomal- but not Z-linked loci, mostly from the pied- to the collared flycatcher. Male plumage characters and genes involved in hybrid fitness are largely mapped to the Z-chromosome (III). By studying mate choice of female hybrids I show that there is a link between female preferences and the Z chromosome (IV). The rate of introgression in island versus clinal hybrid zones is consistent with regional differences in hybrid fertility. Asymmetric gene flow from allopatry on the islands may oppose reinforcement, leading to introgression and a partial breakdown of postzygotic isolation. Adaptive introgression may explain the high rate of introgression observed at one of the genetic markers (V). For late breeding female collared flycatchers it appears to be adaptive to use pied flycatchers as social fathers but conspecific males as genetic fathers. Additionally, females in mixed species pairs may reduce hybridization costs by producing an excess of male hybrid offspring that are more fertile than females (VI). In conclusion, the Z-chromosome appears to play a major role in flycatcher speciation. Sexual selection and reinforcement are important mechanisms in the divergence of these birds. However, gene flow from allopatry, introgression of adaptive genes and adaptive hetrospecific pairing by late breeding collared flycatcher females may work in the opposite direction.
|
|
| 45. |
- Boss, John, et al.
(författare)
-
Gene expression in the brain of a migratory songbird during breeding and migration
- 2016
-
Ingår i: Movement Ecology. - : Springer Science and Business Media LLC. - 2051-3933. ; 4
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: We still have limited knowledge about the underlying genetic mechanisms that enable migrating species of birds to navigate the globe. Here we make an attempt to get insight into the genetic architecture controlling this complex innate behaviour. We contrast the gene expression profiles of two closely related songbird subspecies with divergent migratory phenotypes. In addition to comparing differences in migratory strategy we include a temporal component and contrast patterns between breeding adults and autumn migrating juvenile birds of both subspecies. The two willow warbler subspecies, Phylloscopus trochilus trochilus and P. t. acredula, are remarkably similar both in phenotype and genotype and have a narrow contact zone in central Scandinavia. Here we used a microarray gene chip representing 23,136 expressed sequence tags (ESTs) from the zebra finch Taeniopygia guttata to identify mRNA level differences in willow warbler brain tissue in relation to subspecies and season.RESULTS: Out of the 22,109 EST probe sets that remained after filtering poorly binding probes, we found 11,898 (51.8 %) probe sets that could be reliably and uniquely matched to a total of 6,758 orthologous zebra finch genes. The two subspecies showed very similar levels of gene expression with less than 0.1 % of the probe sets being significantly differentially expressed. In contrast, 3,045 (13.8 %) probe sets were found to be differently regulated between samples collected from breeding adults and autumn migrating juvenile birds. The genes found to be differentially expressed between seasons appeared to be enriched for functional roles in neuronal firing and neuronal synapse formation.CONCLUSIONS: Our results show that only few genes are differentially expressed between the subspecies. This suggests that the different migration strategies of the subspecies might be governed by few genes, or that the expression patterns of those genes are time-structured or tissue-specific in ways, which our approach fails to uncover. Our findings will be useful in the planning of new experiments designed to unravel the genes involved in the migratory program of birds.
|
|
| 46. |
- Brattström, Oskar, et al.
(författare)
-
AFLP reveals cryptic population structure in migratory European red admirals (Vanessa atalanta)
- 2010
-
Ingår i: Ecological Entomology. - : Wiley. - 1365-2311 .- 0307-6946. ; 35:2, s. 248-252
-
Tidskriftsartikel (refereegranskat)abstract
- 2. Using the software STRUCTURE 2.2, we found two distinct genotype clusters present in different frequencies at all study sites. The frequencies of these genotypic clusters varied significantly between years within the same site. Remarkably few individuals were of mixed ancestry, indicating that some isolating mechanisms are present. Twenty-seven mtDNA haplotypes were identified but they showed no geographic structure, nor were they related to either of the two genotype clusters identified in the AFLP data. 3. Most field observations of migrating red admirals suggest a regular north-south migration pattern in Europe. Our data indicate both long-distance migration and a more variable pattern in orientation, since the composition of the two genotypic clusters shows dramatic variation between sites and years in the northern part of the distribution range.
|
|
| 47. |
- Brattström, Oskar, et al.
(författare)
-
Understanding the migration ecology of European red admirals Vanessa atalanta using stable hydrogen isotopes
- 2010
-
Ingår i: Ecography. - : Wiley. - 1600-0587 .- 0906-7590. ; 33:4, s. 720-729
-
Tidskriftsartikel (refereegranskat)abstract
- Tracking migratory movement of small animals with variable migration patterns is difficult with standard mark-recapture methods or genetic analysis. We used stable hydrogen isotope (delta D) measurements of wings from European red admirals Vanessa atalanta to study several aspects of this species' migration. In the central part of southern Europe we found large differences in delta D values between red admirals sampled in autumn and spring supporting the hypothesis that reproduction takes place in the Mediterranean region during winter. There was also an apparent influx to southern Europe in the spring of individuals with a more southerly origin, since many samples had higher delta D values and similar to those expected from coastal areas of North Africa. We found a clear seasonal difference in the delta D values of red admirals sampled in northern Europe. Spring migrants arriving in northern Europe generally had high delta D values that indicated a southerly origin. In autumn, delta D values suggested that red admirals were mostly from regions close to the sampling sites, but throughout the sampling period there were always individuals with delta D values suggesting non-local origins. The migration pattern of this species is supposedly highly variable and plastic. delta D differences between individuals in the western part of Europe were generally small making migratory patterns difficult to interpret. However, butterflies from western Europe were apparently isolated from those from north-eastern Europe, since delta D values in the western region rarely corresponded to those of autumn migrants from the north-east. Use of delta D data for inferring butterfly migration in Europe is complex, but our study showed that this technique can be used to help uncover previously unknown aspects of red admiral migration.
|
|
| 48. |
- Caballero-Lopez, Violeta, et al.
(författare)
-
Transposable elements mark a repeat-rich region associated with migratory phenotypes of willow warblers (Phylloscopus trochilus)
- 2022
-
Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 31:4, s. 1128-1141
-
Tidskriftsartikel (refereegranskat)abstract
- The genetic basis of bird migration has been the focus of several studies. Two willow warbler subspecies (Phylloscopus trochilus trochilus and Phylloscopus trochilus acredula) follow different migratory routes to wintering grounds in Africa. Their breeding populations overlap in contact areas or “migratory divides” located in central Scandinavia and in eastern Poland. Earlier analyses demonstrated that the genetic differences between these two migratory phenotypes are few and cluster on chromosomes 1 and 5. In addition, an amplified fragment length polymorphism-derived biallelic marker (known as WW2) presents steep clines across both migratory divides but failed to be mapped in the genome. Here, we characterize the WW2 marker and describe its two variants (WW2 ancestral and WW2 derived) as portions of long terminal repeat retrotransposons originating from an ancient infection by an endogenous retrovirus. We used quantitative polymerase chain reaction techniques to quantify copy numbers of the WW2 derived variant in the two subspecies and their hybrids. This, together with genome analyses revealed that WW2 derived variants are much more abundant in P. t. acredula and appear embedded in a large repeat-rich region (>12 Mbp), not associated with the divergent regions of chromosomes 1 or 5. However, it might interact with genetic elements controlling migration direction. Testing this hypothesis further will require knowing the exact location of this region, such as by obtaining more complete genome assemblies preferably in combination with techniques like fluorescence in situ hybridization applied to a willow warbler karyotype, and finally to investigate the copy number of this marker in hybrids with known migratory tracks.
|
|
| 49. |
- Çakmak, Emel, et al.
(författare)
-
Genetic diversity is retained in a bottlenecked Cinereous Vulture population in Turkey
- 2019
-
Ingår i: Ibis. - : Wiley. - 0019-1019 .- 1474-919X. ; 161:4, s. 793-805
-
Tidskriftsartikel (refereegranskat)abstract
- Vulture populations worldwide have suffered precipitous declines in recent decades. The Cinereous Vulture Aegypius monachus, a highly philopatric scavenger distributed across southern Europe and the central Asian plateau, is threatened in many parts of its range. Turkey holds the second largest population of this species in the Western Palaearctic, but there has been no research on its genetic structure and the possible implications of this structure for the future of the species. Here we report nuclear diversity and relatedness determined by short tandem repeat genotyping of 81 individuals from the four largest colonies. Our results demonstrated no significant genetic structuring, suggesting a single panmictic metapopulation connected by frequent dispersal. Furthermore, we show that the study population has retained moderate levels of genetic diversity, despite passing through a recent demographic bottleneck. We estimated the effective population size to be 112 individuals (95% confidence interval 74–201). Our results imply that the observed lack of increase in population size since the 1990s has not been caused by lowered fitness due to genetic inbreeding but rather by increased mortality via demographic processes. In the short term, we suggest that conservation efforts should treat the Turkish subpopulations as a single management unit and aim to increase population size through effective protection, especially during the breeding season.
|
|
| 50. |
- Chakarov, Nayden, et al.
(författare)
-
Blood parasites in vectors reveal a united blackfly community in the upper canopy
- 2020
-
Ingår i: Parasites & Vectors. - : Springer Science and Business Media LLC. - 1756-3305. ; 13:1
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The behaviour of blood-sucking arthropods is a crucial determinant of blood protozoan distribution and hence of host-parasite coevolution, but it is very challenging to study in the wild. The molecular identification of parasite lineages in vectors can be a useful key to understand the behaviour and transmission patterns realised by these vectors. METHODS: In this study, we collected blackflies around nests of three raptor species in the upper forest canopy in central Europe and examined the presence of vertebrate DNA and haemosporidian parasites in them. We molecularly analysed 156 blackfly individuals, their vertebrate blood meals, and the haemosporidian parasite lineages they carried. RESULTS: We identified nine species of Simulium blackflies, largely belonging to the subgenera Nevermannia and Eusimulium. Only 1% of the collected specimens was visibly engorged, and only 4% contained remains of host DNA. However, in 29% of the blackflies Leucocytozoon lineages were identified, which is evidence of a previous blood meal on an avian host. Based on the known vertebrate hosts of the recorded Leucocytozoon lineages, we can infer that large and/or abundant birds, such as thrushes, crows, pigeons, birds of prey, owls and tits are the main targets of ornithophilic blackflies in the canopy. Blackfly species contained similar proportions of host group-specific parasite lineages and thus do not appear to be associated with particular host groups. CONCLUSIONS: The Leucocytozoon clade infecting thrushes, crows, and pigeons present in most represented blackfly species suggests a lack of association between hosts and blackflies, which can increase the probability of host switches of blood parasites. However, the composition of the simuliid species differed between nests of common buzzards, goshawks and red kites. This segregation can be explained by coinciding habitat preferences between host and vector, and may lead to the fast speciation of Leucocytozoon parasites. Thus, subtle ecological preferences and lack of host preference of vectors in the canopy may enable both parasite diversification and host switches, and enforce a habitat-dependent evolution of avian malaria parasites and related haemosporidia.
|
|
