| 1. |
|
|
| 2. |
- Arnqvist, Goran, et al.
(författare)
-
Falsk marknadsföring om hållbart skogsbruk
- 2022
-
Ingår i: Svenska Dagbladet Debatt. - 1101-2412.
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Dagens svenska skogsbruk är inte ekologiskt hållbart. Att saluföra det som hållbart är därför – för att tala klarspråk – falsk marknadsföring, skriver forskare.
|
|
| 3. |
- Berlin, Sofia, et al.
(författare)
-
A multilocus assay reveals high nucleotide diversity and limited differentiation among Scandinavian willow grouse (Lagopus lagopus)
- 2008
-
Ingår i: BMC Genetics. - : Springer Science and Business Media LLC. - 1471-2156. ; 9, s. 89-
-
Tidskriftsartikel (refereegranskat)abstract
- Background: There is so far very little data on autosomal nucleotide diversity in birds, except for data from the domesticated chicken and some passerines species. Estimates of nucleotide diversity reported so far in birds have been high (similar to 10(-3)) and a likely explanation for this is the generally higher effective population sizes compared to mammals. In this study, the level of nucleotide diversity has been examined in the willow grouse, a non-domesticated bird species from the order Galliformes, which also holds the chicken. The willow grouse (Lagopus lagopus) has an almost circumpolar distribution but is absent from Greenland and the north Atlantic islands. It primarily inhabits tundra, forest edge habitats and sub-alpine vegetation. Willow grouse are hunted throughout its range, and regionally it is a game bird of great cultural and economical importance. Results: We sequenced 18 autosomal protein coding loci from approximately 15-18 individuals per population. We found a total of 127 SNP's, which corresponds to 1 SNP every 51 bp. 26 SNP's were amino acid replacement substitutions. Total nucleotide diversity (pi(t)) was between 1.30 x 10(-4) and 7.66 x 10(-3) (average pi(t) = 2.72 x 10(-3) +/- 2.06 x 10(-3)) and silent nucleotide diversity varied between 4.20 x 10(-4) and 2.76 x 10(-2) (average pi(S) = 9.22 x 10(-3) +/- 7.43 x 10(-4)). The synonymous diversity is approximately 20 times higher than in humans and two times higher than in chicken. Non-synonymous diversity was on average 18 times lower than the synonymous diversity and varied between 0 and 4.90 x 10(-3) (average pi(a) = 5.08 x 10(-4) +/- 7.43 x 10(3)), which suggest that purifying selection is strong in these genes. F-ST values based on synonymous SNP's varied between -5.60 x 10(-4) and 0.20 among loci and revealed low levels of differentiation among the four localities, with an overall value of F-ST = 0.03 (95% CI: 0.006 -0.057) over 60 unlinked loci. Non-synonymous SNP's gave similar results. Low levels of linkage disequilibrium were observed within genes, with an average r(2) = 0.084 +/- 0.110, which is expected for a large outbred population with no population differentiation. The mean per site per generation recombination parameter (rho) was comparably high (0.028 +/- 0.018), indicating high recombination rates in these genes. Conclusion: We found unusually high levels of nucleotide diversity in the Scandinavian willow grouse as well as very little population structure among localities with up to 1647 km distance. There are also low levels of linkage disequilibrium within the genes and the population recombination rate is high, which is indicative of an old panmictic population, where recombination has had time to break up any haplotype blocks. The non-synonymous nucleotide diversity is low compared with the silent, which is in agreement with effective purifying selection, possibly due to the large effective population size.
|
|
| 4. |
|
|
| 5. |
- Chondrelli, Niki, et al.
(författare)
-
Batrachochytrium dendrobatidis strain affects transcriptomic response in liver but not skin in latitudinal populations of the common toad (Bufo bufo)
- 2024
-
Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 14
-
Tidskriftsartikel (refereegranskat)abstract
- Batrachochytrium dendrobatidis (Bd) is a fungal pathogen that has decimated amphibian populations worldwide for several decades. We examined the changes in gene expression in response to Bd infection in two populations of the common toad, Bufo bufo, in a laboratory experiment. We collected B. bufo eggs in southern and northern Sweden, and infected the laboratory-raised metamorphs with two strains of the global panzoonotic lineage Bd-GPL. Differential expression analysis showed significant differences between infected and control individuals in both liver and skin. The skin samples showed no discernible differences in gene expression between the two strains used, while liver samples were differentiated by strain, with one of the strains eliciting no immune response from infected toads. Immune system genes were overexpressed in skin samples from surviving infected individuals, while in liver samples the pattern was more diffuse. Splitting samples by population revealed a stronger immune response in northern individuals. Differences in transcriptional regulation between populations are particularly relevant to study in Swedish amphibians, which may have experienced varying exposure to Bd. Earlier exposure to this pathogen and subsequent adaptation or selection pressure may contribute to the survival of some populations over others, while standing genetic diversity in different populations may also affect the infection outcome.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Corrales, Carolina, et al.
(författare)
-
Maintenance of gene flow by female-biased dispersal of black grouse, Tetrao tetrix in northern Sweden
- 2012
-
Ingår i: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 153:4, s. 1127-1139
-
Tidskriftsartikel (refereegranskat)abstract
- Sex-biased dispersal is a common phenomenon in most birds. In general, males breed at or near their site of birth while most of the females disperse. We investigated the dispersal patterns and genetic structure of lekking Black Grouse Tetrao tetrix based on ten microsatellite loci. Data for 469 individuals from 25 localities spaced from 45 to 558 km apart revealed low levels of genetic differentiation and high connectivity among studied sites due to female-biased dispersal. The spatial distribution of the genetic variation did not follow an isolation by distance pattern neither for females nor for males. STRUCTURE identified three clusters of male individuals but without any geographical pattern. Only one cluster was identified for females. Several tests of sex-biased dispersal were executed. Most of them showed no difference between sexes, but the mean assignment index and F IS showed a statistically significant female-biased dispersal. Therefore, we consider that the northern Swedish Black Grouse population is a panmictic population. The amount of gene flow throughout time has been consistent with dispersal and with no strong effect of forest fragmentation in the region.
|
|
| 9. |
|
|
| 10. |
- Corrales Duque, Carolina
(författare)
-
Population Genetic Structure of Black Grouse (Tetrao tetrix) : From a Large to a Fine Scale Perspective
- 2011
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Black grouse (Tetrao tetrix) is a bird species with a lek mating system found in the Palearctic boreal taiga. It is assumed that it has a continuous distribution along Scandinavia and Siberia, whereas in Central Europe it has declined during the last decades. The primary objective of this thesis was to obtain a deeper understanding of the history, systematic classification and the genetic structure of black grouse on different geographical scales using microsatellites and control region mtDNA sequences (CR). I determined how much the mating system, habitat fragmentation and historical population processes have influenced the partitioning of genetic diversity in this species. Phylogeographical results are consistent with a demographic population expansion, and the patterns of postglacial dispersal suggest that a glacial refugium was located somewhere in central Asia, and from there black grouse spread out to Europe following the retreat of glacial ice sheets. I suggest that the two European black grouse subspecies, T. t. Tetrix and T. t. britannicus correspond to only one subspecies: T. t. tetrix, and that this lineage has diverged from T.t. viridanus, a subspecies found in Kazakhstan. The British population is significantly divergent from the remaining Eurasian samples for microsatellites but it is not for mtDNA. Therefore, they should regard as a separate Management Unit and not as a subspecies. Furthermore, British black grouse occur in three independent genetic units, corresponding to Wales, northern England/southern Scotland and northern Scotland. There was also genetic structure within Sweden. Habitat fragmentation is the main cause of population genetic structure in southern Swedish black grouse. In contrast, low levels of genetic differentiation and high connectivity were found in northern Sweden due to female-biased dispersal. On a finer geographical scale, I found genetic differences between leks due to a mixture of related and unrelated individuals within leks. However, mean relatedness values hardly differed from zero. Some leks were similar to one another and I interpret this as a result of variation in local reproductive success and philopatry. These factors would cause genetic structuring but this by itself would not reveal that kin selection is operating within black grouse leks.
|
|
| 11. |
- Cortazar-Chinarro, Maria, et al.
(författare)
-
Antimicrobial peptide and sequence variation along a latitudinal gradient in two anurans
- 2020
-
Ingår i: BMC Genetics. - : BMC. - 1471-2156. ; 21:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background While there is evidence of both purifying and balancing selection in immune defense genes, large-scale genetic diversity in antimicrobial peptides (AMPs), an important part of the innate immune system released from dermal glands in the skin, has remained uninvestigated. Here we describe genetic diversity at three AMP loci (Temporin, Brevinin and Palustrin) in two ranid frogs (Rana arvalis and R. temporaria) along a 2000 km latitudinal gradient. We amplified and sequenced part of the Acidic Propiece domain and the hypervariable Mature Peptide domain ( 150-200 bp) in the three genes using Illumina Miseq and expected to find decreased AMP genetic variation towards the northern distribution limit of the species similarly to studies on MHC genetic patterns. Results We found multiple loci for each AMP and relatively high gene diversity, but no clear pattern of geographic genetic structure along the latitudinal gradient. We found evidence of trans-specific polymorphism in the two species, indicating a common evolutionary origin of the alleles. Temporin and Brevinin did not form monophyletic clades suggesting that they belong to the same gene family. By implementing codon evolution models we found evidence of strong positive selection acting on the Mature Peptide. We also found evidence of diversifying selection as indicated by divergent allele frequencies among populations and high Theta k values. Conclusion Our results suggest that AMPs are an important source of adaptive diversity, minimizing the chance of microorganisms developing resistance to individual peptides.
|
|
| 12. |
- Cortazar-Chinarro, Maria, et al.
(författare)
-
Association between the skin microbiome and MHC class II diversity in an amphibian
- 2024
-
Ingår i: Molecular Ecology. - : John Wiley & Sons. - 0962-1083 .- 1365-294X. ; 33:1
-
Tidskriftsartikel (refereegranskat)abstract
- Microbiomes play an important role in determining the ecology and behaviour of their hosts. However, questions remain pertaining to how host genetics shape microbiomes, and how microbiome composition influences host fitness. We explored the effects of geography, evolutionary history and host genetics on the skin microbiome diversity and structure in a widespread amphibian. More specifically, we examined the association between bacterial diversity and composition and the major histocompatibility complex class II exon 2 diversity in 12 moor frog (Rana arvalis) populations belonging to two geographical clusters that show signatures of past and ongoing differential selection. We found that while bacterial alpha diversity did not differ between the two clusters, MHC alleles/supertypes and genetic diversity varied considerably depending on geography and evolutionary history. Bacterial alpha diversity was positively correlated with expected MHC heterozygosity and negatively with MHC nucleotide diversity. Furthermore, bacterial community composition showed significant variation between the two geographical clusters and between specific MHC alleles/supertypes. Our findings emphasize the importance of historical demographic events on hologenomic variation and provide new insights into how immunogenetic host variability and microbial diversity may jointly influence host fitness with consequences for disease susceptibility and population persistence.
|
|
| 13. |
- Cortazar-Chinarro, Maria, et al.
(författare)
-
Drift, selection, or migration? : Processes affecting genetic differentiation and variation along a latitudinal gradient in an amphibian
- 2017
-
Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 17
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Past events like fluctuations in population size and post-glacial colonization processes may influence the relative importance of genetic drift, migration and selection when determining the present day patterns of genetic variation. We disentangle how drift, selection and migration shape neutral and adaptive genetic variation in 12 moor frog populations along a 1700 km latitudinal gradient. We studied genetic differentiation and variation at a MHC exon II locus and a set of 18 microsatellites. Results: Using outlier analyses, we identified the MHC II exon 2 (corresponding to the beta-2 domain) locus and one microsatellite locus (RCO8640) to be subject to diversifying selection, while five microsatellite loci showed signals of stabilizing selection among populations. STRUCTURE and DAPC analyses on the neutral microsatellites assigned populations to a northern and a southern cluster, reflecting two different post-glacial colonization routes found in previous studies. Genetic variation overall was lower in the northern cluster. The signature of selection on MHC exon II was weaker in the northern cluster, possibly as a consequence of smaller and more fragmented populations. Conclusion: Our results show that historical demographic processes combined with selection and drift have led to a complex pattern of differentiation along the gradient where some loci are more divergent among populations than predicted from drift expectations due to diversifying selection, while other loci are more uniform among populations due to stabilizing selection. Importantly, both overall and MHC genetic variation are lower at northern latitudes. Due to lower evolutionary potential, the low genetic variation in northern populations may increase the risk of extinction when confronted with emerging pathogens and climate change.
|
|
| 14. |
- Cortazar-Chinarro, Maria
(författare)
-
Immunogenetic variation along the latitudinal gradient in Scandinavian anuran species : Evolutionary processes, demography and infection
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The evolutionary and demographic processes affecting how genetic variation is partitioned and distributed over large geographical scales is of fundamental importance for our understanding of how organisms may adapt to their environments. Northern peripheral populations generally have lower genetic variation and individuals in these populations may therefore face difficulties adapting to their local environment. At northern latitudes lack of genetic variation could be detrimental in face of newly emerging diseases as a result of anthropogenic actions and warmer climate in these areas. In this thesis, I explore genetic variation and the contemporary evolutionary processes affecting genes involved in the adaptive immune defense (Major Histocompatibility Complex; MHC) and the innate immune defense (AMP; Antimicrobial Peptides) over a large geographical gradient in anuran species (paper I, II and IV). I study signatures of historical selection on the MHC class II exon 2 and AMP (Temporin, Brevinin and Palustrin) sequences in the Signal Peptide and the Acidic Propiece domains (paper II and III). Finally, I investigate potential associations between specific MHC class II exon 2 alleles and a chytrid fungus infection (Bd) in common toads (Bufo bufo) (paper IV). The results reveal that genetic variation of MHC class II exon 2 decreases towards northern latitudes in R. arvalis and B. bufo and have been shaped by complex evolutionary processes (drift, selection, migration) affected by different demographic scenarios. On the other hand, AMP nucleotide variation is divergent among geographical areas, but there is no clear geographical pattern along the same gradient, suggesting diversifying selection as the main force shaping genetic variation. Finally, I found an effect of two specific MHC class II exon 2 alleles on survival in juvenile B. bufo when infected with Bd. In summary, my thesis unravels the complex patterns shaping genetic diversity at large scales. My results may guide conservation practices aiming to prevent amphibian mass mortality events on-going all over the world.
|
|
| 15. |
- Cortazar-Chinarro, Maria, 1985-, et al.
(författare)
-
Latitudinal MHC variation and haplotype associated differential survival in response to experimental infection of two strains of Bd-GPL in common toads
- 2024
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- While both innate and adaptive immune system mechanisms have been implicated in resistance against the chytrid fungusBatrachochytrium dendrobatitis, studies on the role of specific MHC haplotypes onBdinfection are rare. Here, we studied latitudinal variation in MHC Class IIB loci along a latitudinal gradient from southern to northern Sweden in common toads,Bufo bufo. Swedish toad populations had fewer MHC Class IIB haplotypes compared to a previous study of populations in Britain. Furthermore, we found MHC diversity to decline from south to the north within Sweden. The low diversity may compromise the ability of northern populations to fight emerging disease, such as the chytrid fungusBd. In a laboratory experiment, we infected newly metamorphosed toads with two strains of the Global Pandemic Lineage of the fungus (Bd-GPL) and compared survival with sham controls. We foundBd-infected toads had lower survival compared to controls. Survival was dependent onBd-strain and whether experimental toads where collected in the south or the north of Sweden with lower survival in northern individuals. MHC diversity was lower in toads of northern origin, all northern animals being monomorphic for a single MHC haplotype, whereas we found seven different haplotypes in southern animals. Survival of infected animals was dependent on bothBd-strain and MHC haplotype suggesting differential infection dynamics depending on bothBd-strain and host MHC characteristics.
|
|
| 16. |
- Cortazar-Chinarro, Maria, et al.
(författare)
-
Major Histocompatibility Complex Variation and Haplotype Associated Survival in Response to Experimental Infection of Two Bd-GPL Strains Along a Latitudinal Gradient
- 2022
-
Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media S.A.. - 2296-701X. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- While both innate and adaptive immune system mechanisms have been implicated in resistance against the chytrid fungus Batrachochytrium dendrobatidis (Bd), studies on the role of specific MHC haplotypes on Bd infection are rare. Here, we studied variation in MHC Class IIB loci in the common toad Bufo bufo along a latitudinal gradient across Sweden. In general, Swedish toad populations had few MHC Class IIB haplotypes and MHC diversity declined from south (13 haplotypes) to the north (four haplotypes). The low diversity may compromise the ability of northern populations to fight emerging disease, such as Bd. In a laboratory experiment, we infected newly metamorphosed toads with two strains of the Global Pandemic Lineage of the fungus (Bd-GPL) and compared survival with sham controls. Bd-infected toads had lower survival compared to controls. Moreover, survival was dependent on the Bd-strain and northern toads had lower Bd-mediated survival than southern individuals. MHC diversity was lower in northern toads. All northern experimental animals were monomorphic for a single MHC haplotype, whereas we found seven different haplotypes in southern experimental animals. In southern toads, survival was dependent on both Bd-strain and MHC haplotype suggesting differential infection dynamics depending on both Bd-strain and host immune system characteristics.
|
|
| 17. |
- Cortazar-Chinarro, Maria, et al.
(författare)
-
Signatures of historical selection on MHC reveal different selection patterns in the moor frog (Rana arvalis)
- 2018
-
Ingår i: Immunogenetics. - : Springer Science and Business Media LLC. - 0093-7711 .- 1432-1211. ; 70:7, s. 477-484
-
Tidskriftsartikel (refereegranskat)abstract
- MHC genes are key components in disease resistance and an excellent system for studying selection acting on genetic variation in natural populations. Current patterns of variation in MHC genes are likely to be influenced by past and ongoing selection as well as demographic fluctuations in population size such as those imposed by post-glacial recolonization processes. Here, we investigated signatures of historical selection and demography on an MHC class II gene in 12 moor frog populations along a 1700-km latitudinal gradient. Sequences were obtained from 207 individuals and consecutively assigned into two different clusters (northern and southern clusters, respectively) in concordance with a previously described dual post-glacial colonization route. Selection analyses comparing the relative rates of non-synonymous to synonymous substitutions (dN/dS) suggested evidence of different selection patterns in the northern and the southern clusters, with divergent selection prevailing in the south but uniform positive selection predominating in the north. Also, models of codon evolution revealed considerable differences in the strength of selection: The southern cluster appeared to be under strong selection while the northern cluster showed moderate signs of selection. Our results indicate that the MHC alleles in the north diverged from southern MHC alleles as a result of differential selection patterns.
|
|
| 18. |
- Dannewitz, Johan, 1968-
(författare)
-
Genetic and Ecological Consequences of Fish Releases : With Focus on Supportive Breeding of Brown Trout Salmo trutta and Translocation of European Eel Anguilla anguilla
- 2003
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Although the practice of releasing fish into the wild is common in the management and conservation of fish populations, the success of release programmes and the potential harmful genetic and ecological effects that may follow are rarely considered. This thesis focuses on genetic and ecological consequences of fish releases, exemplified by supportive breeding of brown trout (Salmo trutta) and translocation of European eel (Anguilla anguilla). Specific questions addressed include: What is the relative performance of hatchery produced fish released to support wild populations, and do released hatchery fish contribute to the natural productivity? What is the variation in reproductive success in the wild, and how does it affect the genetic consequences of a supportive breeding programme? Is there a spatial genetic structure in the European eel that must be considered in the management of this rapidly declining species?Experiments conducted under natural and near-natural conditions in the River Dalälven, Sweden, suggest that hatchery produced trout can reproduce in the wild. In fact, when the pronounced variation between individual breeders was accounted for, there were no detectable differences between hatchery produced and wild born trout in reproductive success or offspring survival. These results were supported by molecular genetic data suggesting a pronounced gene flow from hatchery to wild trout in the river. Hatchery reared trout were, however, found to exhibit reduced survival rates immediately following release into the wild, an effect that was most likely due to phenotypic responses to the hatchery environment during ontogeny and a lack of experience of the wild.In sharp contrast to recently published studies, the present genetic analyses of European eels sampled across the whole distribution range suggest no spatial genetic structure but a subtle temporal genetic heterogeneity within sampled locations. These results emphasise the need to consider temporal replication when assessing population structure of marine species.The results obtained have general implications for the management and conservation of fish populations. First, supportive breeding of threatened salmonid populations might be successful, not only for boosting the census size and thereby reducing the short-term probability of extinction, but also for reducing the risks of inbreeding depression and loss of adaptive potential in future generations. However, the results also highlight the need to restore the natural productivity of a population under supportive breeding to avoid a potential reduction in fitness due to hatchery selection. Further, the lack of a detectable spatial genetic structure in the European eel suggests that the management strategy of translocating juvenile eels from locations were they are overabundant to other suitable freshwater habitats does not necessarily have to include genetic considerations with respect to the geographical origin of the translocated eels.
|
|
| 19. |
- Ekblom, Robert, et al.
(författare)
-
Balancing selection, sexual selection and geographic structure in MHC genes of Great Snipe
- 2010
-
Ingår i: Genetica. - : Springer Science and Business Media LLC. - 0016-6707 .- 1573-6857. ; 138:4, s. 453-461
-
Tidskriftsartikel (refereegranskat)abstract
- Signatures of balancing selection are often found when investigating the extremely polymorphic regions of major histocompatibility complex (MHC) genes, and it is generally accepted that selective forces maintain this polymorphism. However, the exact nature of the selection is controversial. Theoretical studies have mainly focused on overdominance and/or frequency dependent selection while laboratory studies have emphasised the role of mate choice. Empirical field data, on the other hand, have been relatively scarce. Previously we have found that geographic structure in MHC class II genes of the Great Snipe (Gallinago media) is too pronounced to be explained by neutral forces alone. Here we test the hypothesis that sexual selection on MHC alleles may be influencing this geographic structure between mountain and lowland populations. We found evidence of balancing selection acting on MHC genes in the form of a higher rate of amino-acid changing substitutions compared to silent substitutions in the peptide binding regions. Not only natural selection but also sexual selection may influence MHC polymorphism in this bird because certain MHC alleles have been found to be associated with higher male mating success. Contrary to predictions from negative frequency dependent selection, males carrying locally rare alleles did not have a mating advantage. Instead, the mating success of alleles in a mountain population was positively correlated to their relative frequency in the mountains compared to the lowlands, implying that locally adapted MHC alleles may also be favoured by sexual selection.
|
|
| 20. |
- Ekblom, Robert, et al.
(författare)
-
Female choice and male humoral immune response in the lekking great snipe (Gallinago media)
- 2005
-
Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 16:2, s. 346-351
-
Tidskriftsartikel (refereegranskat)abstract
- Parasites and diseases constitute major evolutionary forces in many natural populations, and thus having an efficient immune defense to resist infections is crucial for many organisms. Properties of the immune response may also influence mate choice decisions in many animals. Theory predicts several advantages for females when choosing males with superior immune systems. These benefits can be both direct (e.g. increased paternal care and reduced disease transmission) and indirect (good genes). We have investigated female choice with respect to antibody response to two novel antigens in males of a lekking bird, the great snipe (Gallinago media). Because of the lek mating system, female choice probably mainly incurs indirect (genetic) rather than direct benefits. Males responded to vaccination with diphtheria and tetanus toxoids by producing specific antibodies to both antigens. Triggering the immune system had no negative impact on display activities or survival. Males that were chosen by females as mates had on average higher antibody response to the tetanus antigen than their neighbors. We did not, however, find any covariance between the strength of the antibody response and male mating success.
|
|
| 21. |
|
|
| 22. |
- Ekblom, Robert, 1976-
(författare)
-
Immunoecology of the Great Snipe (Gallinago media) : Mate Choice, MHC Variation, and Humoral Immunocompetence in a Lekking Bird
- 2004
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- At the centre of the vertebrate immune system is a group of proteins called MHC (major histocompatibility complex) molecules. These function in self – non self recognition and activation of the immune defence against intruding parasites and pathogens. In this thesis I have investigated individual variation in MHC class II genes and antibody producing ability in relation to ecology and behaviour in the great snipe (Gallinago media), a lekking bird, breeding in northern Europe. There was much variation in the MHC genes of the great snipe and the sequence data show that balancing selection has been acting on these genes. I found genetic differentiation in the MHC between two separate geographic regions of the great snipe distribution. Furthermore, this structure was more pronounced than that previously found in neutral genetic markers, suggesting that different selection pressures (possibly resulting from variation in parasitic fauna) are acting in these different regions. The birds produced specific antibodies following injection with two novel antigens. Males that were chosen as mates, had higher antibody titers than their neighbouring males, suggesting that this ability may be important in female mate choice. Such choice could give the offspring an enhanced immune system or could favour females directly by avoidance of sexually transmitted diseases. Females choosing to mate with a male having a different set of MHC genes than their own could give the offspring immune system the ability to react to a wide range of parasites. No such mate choice could, however, be found in the great snipe. Instead, females preferred males with certain MHC alleles, irrespective of their own MHC type. If those alleles confer resistance to parasites currently prevailing in the population, such resistance would be inherited by the offspring, thereby enhancing their fitness.
|
|
| 23. |
- Ekblom, Robert, et al.
(författare)
-
Major histocompatibility complex variation and mate choice in a lekking bird, the great snipe (Gallinago media)
- 2004
-
Ingår i: Molecular Ecology. - 0962-1083 .- 1365-294X. ; 13:12, s. 3821-3828
-
Tidskriftsartikel (refereegranskat)abstract
- Genes of the major histocompatibility complex (MHC) play a major part in the activation of the vertebrate immune system. In addition, they also appear to function as cues for mate choice. In mammals especially, several kinds of MHC-dependent mate choice have been hypothesized and observed. These include choice of mates that share no or few alleles with the choosing individual, choice of mates with alleles that differ as much as possible from the choosing individual, choice of heterozygous mates, choice of certain genotypes and choice of rare alleles. We investigated these different aspects of mate choice in relation to MHC in a lekking bird species, the great snipe (Gallinago media). We found no evidence for MHC disassortative mating, no preference for males with many MHC alleles and no preference for rare alleles. However, we did find that some allelic lineages were more often found in males with mating success than in males without mating success. Females do not seem to use themselves as references for the MHC-dependent mate choice, rather they seem to prefer males with certain allele types. We speculate that these alleles may be linked to resistance to common parasites.
|
|
| 24. |
- Ekblom, Robert, et al.
(författare)
-
Patterns of polymorphism in the MHC class II of a non-passerine bird, the great snipe (Gallinago media)
- 2003
-
Ingår i: Immunogenetics. - : Springer Science and Business Media LLC. - 0093-7711 .- 1432-1211. ; 54:10, s. 734-741
-
Tidskriftsartikel (refereegranskat)abstract
- The genomic organisation of the major histocompatibility complex (MHC) seems to vary considerably between different bird species. In order to understand this variation it is important to gather information from different species. We have, for the first time, investigated MHC class 11 polymorphism in a wader species, the great snipe (Gallinago media). Eleven alleles were found in five sequenced individuals; these come from at least three different loci, but RFLP data suggest that a larger number of genes may be present. For MHC genes, amino acid substitutions followed the, for MHC genes, general pattern of high non-synonymous substitution rates in peptide-binding regions, suggesting that the sequenced alleles may be expressed. The number of genes, lengths of introns and exon sequences of the great snipe MHC seem to be intermediate between those of chicken and passerine birds.
|
|
| 25. |
|
|
| 26. |
- Ekblom, Robert, et al.
(författare)
-
Spatial pattern of MHC class II variation in the great snipe (Gallinago media)
- 2007
-
Ingår i: Molecular Ecology. - 0962-1083 .- 1365-294X. ; 16:7, s. 1439-1451
-
Tidskriftsartikel (refereegranskat)abstract
- The genes of the major histocompatibility complex (MHC) code for proteins involved in antigen recognition and triggering of the adaptive immune response, and are therefore likely to be under selection from parasites. These selection regimes may vary in space and time. Here we report a strong geographical structure in MHC class II B genes of a migrating bird, the great snipe (Gallinago media). Genetic differentiation in the MHC between two ecologically distinct distributional regions (Scandinavian mountain populations vs. East European lowland populations) was still present after statistically controlling for the effect of selectively neutral variation (microsatellites) using partial Mantel tests. This suggests a role for selection in generating this spatial structure and that it represents local adaptation to different environments. Differentiation between populations within the two regions was negligible. Overall, we found a high number of MHC alleles (50, from 175 individuals). This, together with a tendency for a higher rate of nonsynonymous than synonymous substitutions in the peptide binding sites, and high Tajima's D in certain regions of the gene, suggests a history of balancing selection. MHC variation is often thought to be maintained by some form of balancing selection, but the nature of this selection remains unclear. Our results support the hypothesis that spatial variation in selection regimes contributes to the high polymorphism.
|
|
| 27. |
|
|
| 28. |
- Fisher, Matthew C., et al.
(författare)
-
Development and worldwide use of non-lethal, and minimal population-level impact, protocols for the isolation of amphibian chytrid fungi
- 2018
-
Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Parasitic chytrid fungi have emerged as a significant threat to amphibian species worldwide, necessitating the development of techniques to isolate these pathogens into culture for research purposes. However, early methods of isolating chytrids from their hosts relied on killing amphibians. We modified a pre-existing protocol for isolating chytrids from infected animals to use toe clips and biopsies from toe webbing rather than euthanizing hosts, and distributed the protocol to researchers as part of the BiodivERsA project RACE; here called the RML protocol. In tandem, we developed a lethal procedure for isolating chytrids from tadpole mouthparts. Reviewing a database of use a decade after their inception, we find that these methods have been applied across 5 continents, 23 countries and in 62 amphibian species. Isolation of chytrids by the non-lethal RML protocol occured in 18% of attempts with 207 fungal isolates and three species of chytrid being recovered. Isolation of chytrids from tadpoles occured in 43% of attempts with 334 fungal isolates of one species (Batrachochytrium dendrobatidis) being recovered. Together, these methods have resulted in a significant reduction and refinement of our use of threatened amphibian species and have improved our ability to work with this group of emerging pathogens.
|
|
| 29. |
- Florin, Ann-Britt, et al.
(författare)
-
Absence of population structure of turbot (Psetta maxima) in the Baltic Sea
- 2007
-
Ingår i: Molecular Ecology. - 0962-1083 .- 1365-294X. ; 16:1, s. 115-126
-
Tidskriftsartikel (refereegranskat)abstract
- We found low, albeit significant, genetic differentiation among turbot (Psetta maxima) in the Baltic Sea but in contrast to earlier findings we found no evidence of isolation by distance. In fact temporal variation among years in one locality exceeded spatial variation among localities. This is an unexpected result since adult turbot are sedentary and eggs are demersal at the salinities occurring in the Baltic. Our findings are most likely explained by the fact that we sampled fish that were born after/during a large influx of water to the Baltic Sea, which may have had the consequence that previously locally and relatively sedentary populations became admixed. These results suggest that populations that colonize relatively variable habitats, like the Baltic, face problems. Any adaptations to local conditions that may build up during stable periods may quickly become eroded when conditions change and/or when populations become admixed. Our results indicate that the ability of turbot to survive and reproduce at the low salinity in the Baltic is more likely due to phenotypic plasticity than a strict genetic adaptation to low salinity.
|
|
| 30. |
- Formenti, Giulio, et al.
(författare)
-
The era of reference genomes in conservation genomics
- 2022
-
Ingår i: Trends in Ecology & Evolution. - : Elsevier. - 0169-5347 .- 1872-8383. ; 37:3, s. 197-202
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Progress in genome sequencing now enables the large-scale generation of reference genomes. Various international initiatives aim to generate reference genomes representing global biodiversity. These genomes provide unique insights into genomic diversity and architecture, thereby enabling comprehensive analyses of population and functional genomics, and are expected to revolutionize conservation genomics.
|
|
| 31. |
- Forsberg, Lars
(författare)
-
Genetic Aspects of Sexual Selection and Mate Choice in Salmonids
- 2008
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The long-term genetic consequences of supportive breeding programs are not well understood. Nevertheless, stocking populations with hatchery-produced fish to compensate for losses of natural production are common practice, for example after constructions of hydroelectric power dams. Hatcheries typically fertilize eggs using ‘mixed-milt fertilizations’, without consideration to natural reproductive behaviours, and hence, natural selective regimes would be altered. Here, a series of experiments with focus on Mhc and mate choice in a population of brown trout (Salmo trutta L.) with a history of long-term stocking are presented. The major histocompatibility complex (Mhc) constitutes of genes coding for antigen presentation in the vertebrate immune system. In addition to the immunological function, Mhc genes might also influence reproductive behaviours such as mate choice. For example, in some species individuals are able to recognize Mhc genotypes of potential mates and to some extent base their mate choice on this information. Here, I address these questions on brown trout. Can the phenomena be observed in brown trout? Could such mechanisms help individuals to avoid inbreeding, or are other mechanisms important? How does the artificial rearing of fish for enhancement of natural populations relate to these issues? The results presented here, in combination with previous work, shows that several factors are important in the process of pair formation in salmonid species. For example, females of the studied population used more than a single criterion when choosing among the available mates Mhc genes and males with certain Mhc genotypes achieved more matings, possibly an effect from increased fighting ability. Further, the population appears to contain an unnatural high level of Mhc variation, and some results indicate that the population might suffer from outbreeding depression at the Mhc. These negative effects are most likely derived from compression of sub-populations after dam-construction, in combination with supportive breeding with no consideration to natural spawning behaviour.
|
|
| 32. |
- Graham, Stuart, et al.
(författare)
-
The utility of effective population size in population management 1 : estimating contemporary effective size
- 2016
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Estimates of effective population size (Ne) are highly desirable in managed populations because they are informative of the rate at which genetic variation is being lost through the processes of genetic drift or inbreeding. Due to the notorious difficulty of accurate Ne estimation in natural populations, myriad estimation methods have been developed over the last 50 years. Conservation practitioners and researchers who are unfamiliar with the Ne estimation literature are now faced with an overwhelming amount of choice when selecting an estimation method and, unfortunately, the resources available to help them make this decision rarely consider the practicalities of implementing these methods. This review aims to alleviate this problem by explicitly considering these practicalities while describing and comparing the most popular estimation methods available. We begin by clearly describing how estimates of Ne can be used in population management. We then go on to describe the most popular methods available for Ne estimation, stating the assumptions that are made and the data that are required. The review concludes with recommendations of the most appropriate estimation methods given specific motivations for estimating Ne and the types of data that are practical to collect.
|
|
| 33. |
|
|
| 34. |
- Halvarsson, Peter
(författare)
-
Host-Parasite Interactions in Natural Populations
- 2016
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Parasitism is one of the most common ways of living and it has arised in many taxa. Parasites feed and live inside or on their hosts resulting in both long and short term consequences for the host. This thesis is exploring the phenotypic and genotypic effects of animals living with parasitic infections. I have been studying three different parasite groups and their associated host species: the great snipe, a lekking freshwater wader bird that migrates between Africa and Northern Europe; the tree sparrow, a stationary passerine found close to human settlements and lastly the water vole, a large rodent living in riparian habitats.Avian malaria is one of the most commonly studied parasites affecting birds. Atoxoplasma, an intestinal protozoan parasite is less studied but is thought to be endemic in free-ranging birds. Given the freshwater habitat great snipes inhabit, a prevalence of 30% avian malaria infections is not high and that the prevalence fluctuated among years. Sequencing of the avian malaria cytochrome b gene revealed that parasites are similar to avian malaria parasites found in African birds suggesting that they were infected on the wintering grounds in Africa. Tree sparrows had few malaria infected individuals, a result that is consistent with other studies of stationary birds at high latitudes. Atoxoplasma infections were common in tree sparrows and capture-recapture analyses show decreased survival in infected compared to uninfected birds and signs of lower mating success among infected.Genetic analyses comparing the transcriptome between mated and unmated great snipe males revealed that the genotype is important for mating success and health status for some of the expressed genes. That variations in some of these genes are involved in maintaining a good health status and mating success supports handicap models for sexual selection in this lek mating system.The major histocompatibility complex (MHC) is a part of the immune system and it contains genes involved in immune response. In water voles, a number of new MHC alleles were identified. Based on their in silico phenotype they were grouped into supertypes to facilitate studies on how helminth infections affect the MHC diversity in the water voles. Some of these MHC supertypes provided resistance to one helminth species, but the same supertype caused the opposite effect for other helminth parasites. Overall, parasites are a driving force for maintaining genetic diversity and parasite infections lowers survival rate, which would lead to a lower lifetime breeding success.
|
|
| 35. |
- Halvarsson, Peter, 1976-
(författare)
-
On the Effects of Blood Parasites in Wild Birds
- 2013
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Coccidian and haemoatozoan parasites are commonly occurring endo-parasites in wild birds and prevalence can vary among species and populations. In addition to prevalence studies, parasites are often used to investigate effects on life history traits. Findings from these studies are not unambiguous, as correlations with many life history traits are absent, although common findings include negative effects on survival and body condition. In this thesis, coccidian and blood parasite prevalence and their effect on survival were investigated using a PCR approach in eleven popu-lations of great snipes (Gallinago media) and in two populations of tree sparrows (Passer montanus). In great snipes and tree sparrows we investigated the parasites Plasmodium/Haemoproteus (P/H) and Leucocytozoon and in tree sparrows also Atoxoplasma.In Great snipes the overall adult prevalence was 29.9%. At the main study site, Gåvålia, Norway, a decrease in P/H prevalence with age was found and infected birds had a lower mean age. Two not mutually exclusive alternative explanations are that infected young birds may have a higher mortality and/or that individual birds can purge the infection. There was a variation in prevalence among the sample years in Gåvålia and a difference among populations. Finding fluctuations among year demonstrates the need of long term data to study parasite prevalence variation. In tree sparrows the Haematozoan prevalence was 5.9% in adults and 56.5% in Atoxoplasma. By using recapture models to estimate apparent survival rates with the software MARK 4.2, it was suggested that parasite infections may have an impact on the apparent survival rate in one of the populations. Since condition and breeding performance appeared unaffected, it can be hypothesised that this pattern may indicate that chronic infections generally do not appear to impair birds, although subclinical infections may occasionally develop into disease with fatal outcome.
|
|
| 36. |
- Hartman, Göran, et al.
(författare)
-
Trends and population dynamics of a Velvet Scoter (Melanitta fusca) population : influence of density dependence and winter climate
- 2013
-
Ingår i: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 154:3, s. 837-847
-
Tidskriftsartikel (refereegranskat)abstract
- As many seaduck populations around the world have been reported to be in decline, there is an increasing demand for knowledge about intrinsic and extrinsic factors determining population dynamics of these species. In this study, we analyzed long-term dynamics of the summer population of Velvet Scoters (Melanitta fusca) breeding in the Aland archipelago in the Baltic Sea; in particular, we examined the influence of winter weather and density dependence on population change. The studied population exhibited substantial fluctuations but only a weak negative trend during the total period of 58 years (1949-2007), and no significant trend at all during the latter three decades of the study (1977-2007). We tested for density dependence and incorporated the winter North Atlantic Oscillation index into the model to test for effects of winter conditions. Our final model explained 56.3 % of the variance of population growth of the studied population. Delayed density dependence explained 29.7 %, pre-breeding climate 8.3 %, and post-breeding climate 18.3 % of the variance. That breeding success is density dependent in a delayed manner is in accordance with the apprehension that Velvet Scoters breed at the age of 2 years. We conclude that density dependence and winter conditions must be taken into consideration when discussing population changes in seaducks in general and the Velvet Scoter in particular.
|
|
| 37. |
- Höglund, Jacob, et al.
(författare)
-
A Chromosome-Level Genome Assembly and Annotation for the Clouded Apollo Butterfly (Parnassius mnemosyne) : A Species of Global Conservation Concern
- 2024
-
Ingår i: Genome Biology and Evolution. - : Oxford University Press. - 1759-6653. ; 16:2
-
Tidskriftsartikel (refereegranskat)abstract
- The clouded apollo (Parnassius mnemosyne) is a palearctic butterfly distributed over a large part of western Eurasia, but population declines and fragmentation have been observed in many parts of the range. The development of genomic tools can help to shed light on the genetic consequences of the decline and to make informed decisions about direct conservation actions. Here, we present a high-contiguity, chromosome-level genome assembly of a female clouded apollo butterfly and provide detailed annotations of genes and transposable elements. We find that the large genome (1.5 Gb) of the clouded apollo is extraordinarily repeat rich (73%). Despite that, the combination of sequencing techniques allowed us to assemble all chromosomes (nc = 29) to a high degree of completeness. The annotation resulted in a relatively high number of protein-coding genes (22,854) compared with other Lepidoptera, of which a large proportion (21,635) could be assigned functions based on homology with other species. A comparative analysis indicates that overall genome structure has been largely conserved, both within the genus and compared with the ancestral lepidopteran karyotype. The high-quality genome assembly and detailed annotation presented here will constitute an important tool for forthcoming efforts aimed at understanding the genetic consequences of fragmentation and decline, as well as for assessments of genetic diversity, population structure, inbreeding, and genetic load in the clouded apollo butterfly.
|
|
| 38. |
- Höglund, Jacob, et al.
(författare)
-
Blood transcriptomes and de novo identification of candidate loci for mating success in lekking great snipe (Gallinago media)
- 2017
-
Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 26:13, s. 3458-3471
-
Tidskriftsartikel (refereegranskat)abstract
- We assembled the great snipe blood transcriptome using data from fourteen lekking males, in order to de novo identify candidate genes related to sexual selection, and determined the expression profiles in relation to mating success. The three most highly transcribed genes were encoding different haemoglobin subunits. All tended to be overexpressed in males with high mating success. We also called single nucleotide polymorphisms (SNPs) from the transcriptome data and found considerable genetic variation for many genes expressed during lekking. Among these, we identified 14 polymorphic candidate SNPs that had a significant genotypic association with mating success (number of females mated with) and/or mating status (mated or not). Four of the candidate SNPs were found in HBAA (encoding the haemoglobin a-chain). Heterozygotes for one of these and one SNP in the gene PABPC1 appeared to enjoy higher mating success compared to males homozygous for either of the alleles. In a larger data set of individuals, we genotyped 38 of the identified SNPs but found low support for consistent selection as only one of the zygosities of previously identified candidate SNPs and none of their genotypes were associated with mating status. However, candidate SNPs generally showed lower levels of spatial genetic structure compared to noncandidate markers. We also scored the prevalence of avian malaria in a subsample of birds. Males infected with avian malaria parasites had lower mating success in the year of sampling than noninfected males. Parasite infection and its interaction with specific genes may thus affect performance on the lek.
|
|
| 39. |
|
|
| 40. |
- Höglund, Jacob, et al.
(författare)
-
Genetic structure among black grouse in Britain : implications for designing conservation units
- 2011
-
Ingår i: Animal Conservation. - : Wiley. - 1367-9430 .- 1469-1795. ; 14:4, s. 400-408
-
Tidskriftsartikel (refereegranskat)abstract
- Black grouse in Britain have faced contraction of their range and have declined in numbers during the recent decades. As such, the species is a conservation concern in the UK. In order to aid conservation decisions, the terms Evolutionary Significant Unit (ESU) and Management Unit (MU) have been proposed. An ESU is an independently evolving evolutionary lineage defined by being reciprocally monophyletic for mitochondrial alleles, and which is significantly different from other lineages with regard to nuclear alleles, whereas an MU is operationally defined by only the latter criterion. Using mitochondrial sequences and nuclear microsatellite loci, we failed to find evidence that British black grouse is an ESU. However, British black grouse are sufficiently different from continental black grouse both with respect to mitochondrial and nuclear data to regard them as a separate MU. Furthermore, we present genetic data which suggest that British black grouse presently occur in what are probably three demographically independent units (roughly corresponding to Wales, northern England/southern Scotland and northern Scotland), which are genetically differentiated. The two southern units (Wales and northern England/southern Scotland) have lower genetic diversity and show signs of having lost genetic variability
|
|
| 41. |
- Höglund, Jacob
(författare)
-
Genetic studies of black grouse with special reference to conservation biology : a review
- 2009
-
Ingår i: Folia zoologica (Brno). - 0139-7893 .- 1573-1189. ; 58:2, s. 135-149
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper I review genetic studies of black grouse to date. The topics cover different areas such as reproductive biology, mating system and, more recently, conservation genetics. The accumulated evidence shows that in the western part of the range of the species, Populations are genetically differentiated. Furthermore, small and isolated populations have lost genetic variation due to increased levels of inbreeding and genetic drift. So far the vast majority of studies have been based on microsatellites. More recent investigations have employed sequence data as well as methods to study quantitative trait variation. These latter Studies may aid in resolving the issue of whether local Populations show any evidence of being adapted to local conditions. This is an important consideration in conservation biology since it determines the extent to which populations are interchangeable and which populations should be used for restocking if such are considered of value.
|
|
| 42. |
- Höglund, Jacob, et al.
(författare)
-
Genetic variability in European black grouse (Tetrao tetrix)
- 2007
-
Ingår i: Conservation Genetics. - : Springer Science and Business Media LLC. - 1566-0621 .- 1572-9737. ; 8:1, s. 239-243
-
Tidskriftsartikel (refereegranskat)abstract
- We studied microsatellite genetic variation in 14 different geographic populations of black grouse (Tetrao tetrix) across the European range. Populations were grouped in three different fragmentation categories: isolated, contiguous and continuous, respectively. Genetic diversity, measured as observed heterozygosity (H O), expected heterozygosity (H E) and allelic richness, were lower in isolated populations as compared to the other two categories that did not differ amongst one another. These results imply that lowered genetic variability in black grouse populations is negatively affected by population isolation. Our results suggest that the connectivity of small and isolated populations in Western Europe should be improved or else these face an increased risk of extinction due to genetic and demographic stochasticity.
|
|
| 43. |
- Höglund, Jacob, et al.
(författare)
-
Genetic variation and structure in Scandinavian red deer (Cervus elaphus) : influence of ancestry, past hunting, and restoration management
- 2013
-
Ingår i: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 109:1, s. 43-53
-
Tidskriftsartikel (refereegranskat)abstract
- In the 19th century, the red deer (Cervus elaphus) population in Sweden experienced a rapid decline in numbers and distribution. A small population was, however, remnant in the southernmost province (Skane) of the country, presumably corresponding to the nominate form of red deer (Cervus elaphus elaphusLinnaeus, 1758). After management, reintroductions, and supplementary release during the 20th century the Swedish C.elaphus population recovered. The recovery was partially uncontrolled, and included introductions of C.elaphus of continental origin. In northern central Sweden (Jamtland) the current C.elaphus population may stem from natural colonization from Norway and/or from specimens of Swedish origin that have escaped from enclosures. To evaluate the status of the current, partially separated populations, we investigated variation at microsatellite markers in 157 C.elaphus specimens from ten locations in Sweden and Norway. Analyses suggest that the highest-likelihood phylogenetic structure among the individuals sampled is described four distinct genetic clusters: (1) animals from the province of Vastergotland in south-western Sweden; (2) deer from the southernmost province of Skane; (3) deer from the provinces Jamtland, Blekinge, and Vastmanland; and (4) Norwegian deer. Cervus elaphus from a captive herd at the Skane Zoo cluster with deer from Skane or deer from Vastergotland, depending on the method of analysis. A number of populations in Sweden may genetically match the nominate form of red deer (C.e.elaphus). The recently established C.elaphus population in Jamtland seems to stem mainly from escapees from enclosures, with a mixed ancestry from the wild remnant population in Skane and continental deer, whereas the influx from Norway is minor, if any. Our results show the need for a detailed assessment of genetic differentiation, and emphasize the value of local management plans when planning and managing introductions.
|
|
| 44. |
- Höglund, Jacob, et al.
(författare)
-
Low MHC variation in isolated island populations of the Natterjack toad (Bufo calamita)
- 2015
-
Ingår i: Conservation Genetics. - : Springer Science and Business Media LLC. - 1566-0621 .- 1572-9737. ; 16:4, s. 1007-1010
-
Tidskriftsartikel (refereegranskat)abstract
- We studied variation at the class II gene of the major histocompatibility complex (MHC) in Natterjack toad populations (Bufo [Epidalea] calamita) on islands off the west coast of Sweden. These isolated populations have previously been shown to exhibit low levels of neutral genetic variation. On seven investigated islands we found only two different MHC alleles, indicating that the genetic variation at this locus is also low. The two alleles were found in all populations, although in one population there was only a single heterozygous individual. The Swedish toads showed similar low levels of MHC variation as revealed by previously published data from populations in northern Europe. We did not find a correlation between MHC and neutral genetic variation (as determined by AFLP). However, our findings show that reduced genetic variation in the Swedish Natterjack toads is not restricted to neutral markers, but is likewise reflected at the MHC.
|
|
| 45. |
- Höglund, Jacob, et al.
(författare)
-
Low neutral and immunogenetic diversity in northern fringe populations of the green toad Bufotes viridis : implications for conservation
- 2022
-
Ingår i: Conservation Genetics. - : Springer Nature. - 1566-0621 .- 1572-9737. ; 23, s. 139-149
-
Tidskriftsartikel (refereegranskat)abstract
- Genetic variation is often lower at high latitudes, which may compromise the adaptability and hence survival of organisms. Here we show that genetic variability is negatively correlated with northern latitude in European green toads (Bufotes viridis). The result holds true for both putatively neutral microsatellite variation and supposedly adaptive MHC Class IIB variation. In particular, our findings have bearing on the conservation status of this species in Sweden, on the northern limit of its distribution where local populations are small and fragmented. These genetically impoverished populations are closely related to other populations found around the Baltic Sea basin. The low neutral and adaptive variation in these fringe populations compared to population at central ranges confirms a pattern shared across all other amphibians so far studied. In Sweden, the situation of green toads is of concern as the remaining populations may not have the evolutionary potential to cope with present and future environmental challenges.
|
|
| 46. |
- Höglund, Jacob, et al.
(författare)
-
Phylogeography of the Black-tailed Godwit Limosa limosa : substructuring revealed by mtDNA control region sequences
- 2009
-
Ingår i: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 150:1, s. 45-53
-
Tidskriftsartikel (refereegranskat)abstract
- Black-tailed (Limosa limosa) and Hudsonian Godwits (L. haemastica) are sometimes described as a superspecies. The Black-tailed Godwit is further split into three subspecies on the basis of morphological differences ( L. l. limosa, L. l. islandica and L. l. melanuroides). We studied variation in partial mtDNA control region sequences among Black-tailed and Hudsonian Godwits which showed 5% divergence. Black-tailed and Hudsonian Godwits were thus clearly differentiated and the separate species status for the two taxa is validated. All three subspecies described for the Black-tailed Godwit had unique haplotypes but the genetic distances were small (0.3-0.6%). Despite small genetic differences we could not detect any substantial gene flow between any of the subspecies as haplotypes were private to each subspecies. Thus, genetic variation within Black-tailed Godwits showed a clear geographic structure. We found a high proportion of rare private haplotypes in three fringe populations of the nominate subspecies of the Black-tailed Godwit (L. l. limosa) where godwits breed in low numbers, but no genetic variation at all in a sample from the Netherlands where godwits are abundant. This suggests that Dutch Godwits may have been affected by a founder effect.
|
|
| 47. |
- Höglund, Jacob, et al.
(författare)
-
Phylogeography of willow grouse (Lagopus lagopus) in the Arctic : taxonomic discordance as inferred from molecular data
- 2013
-
Ingår i: Biological Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4066 .- 1095-8312. ; 110:1, s. 77-90
-
Tidskriftsartikel (refereegranskat)abstract
- Using independently segregating nuclear single nucleotide polymorphisms (SNPs) and mitochondrial control region sequences, we found an east-west division among sampled willow grouse Lagopus lagopus subspecies. This division cut across the range of the subspecies with the largest distribution (lagopus) and thus contradicted existing taxonomic classifications. Russian Lagopus lagopus lagopus tended to cluster with North American willow grouse partly classified as other subspecies. Scandinavian willow grouse (L.l. lagopus) clustered with red grouse from Britain and Ireland (Lagopus lagopus scoticus and Lagopus lagopus hibernicus) but substructuring confirmed the monophyly of the latter. In North America, we could not detect any major genetic divisions apart from two birds described as alexandrae from the Heceta Island (Alaska) when using mitochondrial sequences. Other samples from North America were intermingled regardless of whether they were described as muriei, alexandrae or lagopus. A specimen described as alexandrae was to some extent distinct when analysing the SNP data. The genetic analyses indicated some concordance between genetics and taxonomy but not complete congruence. This is particularly evident for mitochondrial DNA network analyses. We suggest that the taxonomy of this species would benefit by a careful re-examination of the available evidence for subspecies. It appears as if subspecies status is a poor proxy for assigning evolutionary significant units and management units in this species.
|
|
| 48. |
|
|
| 49. |
|
|
| 50. |
- Jensen, Axel, et al.
(författare)
-
Whole genome sequencing reveals high differentiation, low levels of genetic diversity and short runs of homozygosity among Swedish wels catfish
- 2021
-
Ingår i: Heredity. - : Nature Publishing Group. - 0018-067X .- 1365-2540. ; 127, s. 79-91
-
Tidskriftsartikel (refereegranskat)abstract
- The use of genetic markers in the context of conservation is largely being outcompeted by whole-genome data. Comparative studies between the two are sparse, and the knowledge about potential effects of this methodology shift is limited. Here, we used whole-genome sequencing data to assess the genetic status of peripheral populations of the wels catfish (Silurus glanis), and discuss the results in light of a recent microsatellite study of the same populations. The Swedish populations of the wels catfish have suffered from severe declines during the last centuries and persists in only a few isolated water systems. Fragmented populations generally are at greater risk of extinction, for example due to loss of genetic diversity, and may thus require conservation actions. We sequenced individuals from the three remaining native populations (Baven, Eman, and Mockeln) and one reintroduced population of admixed origin (Helge a), and found that genetic diversity was highest in Eman but low overall, with strong differentiation among the populations. No signature of recent inbreeding was found, but a considerable number of short runs of homozygosity were present in all populations, likely linked to historically small population sizes and bottleneck events. Genetic substructure within any of the native populations was at best weak. Individuals from the admixed population Helge a shared most genetic ancestry with the Baven population (72%). Our results are largely in agreement with the microsatellite study, and stresses the need to protect these isolated populations at the northern edge of the distribution of the species.
|
|
