| 1. |
- Strand, Tanja, et al.
(författare)
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The MHC class II of the Black grouse (Tetrao tetrix) consists of low numbers of B and Y genes with variable diversity and expression
- 2007
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Ingår i: Immunogenetics. - : Springer Science and Business Media LLC. - 0093-7711 .- 1432-1211. ; 59:9, s. 725-734
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Tidskriftsartikel (refereegranskat)abstract
- We found that the Black grouse (Tetrao tetrix) possess low numbers of Mhc class II B (BLB) and Y (YLB) genes with variable diversity and expression. We have therefore shown, for the first time, that another bird species (in this case, a wild lek-breeding galliform) shares several features of the simple Mhc of the domestic chicken (Gallus gallus). The Black grouse BLB genes showed the same level of polymorphism that has been reported in chicken, and we also found indications of balancing selection in the peptide-binding regions. The YLB genes were less variable than the BLB genes, also in accordance with earlier studies in chicken, although their functional significance still remains obscure. We hypothesize that the YLB genes could have been under purifying selection, just as the mammal Mhc-E gene cluster.
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| 2. |
- Segelbacher, Gernot, et al.
(författare)
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Analyses of historical and current populations of black grouse in Central Europe reveal strong effects of genetic drift and loss of genetic diversity
- 2014
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Ingår i: Conservation Genetics. - : Springer Science and Business Media LLC. - 1566-0621 .- 1572-9737. ; 15:5, s. 1183-1195
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Tidskriftsartikel (refereegranskat)abstract
- Black grouse (Tetrao tetrix) in Central Europe have undergone a severe contraction of their range in recent decades with only a few small isolated remaining populations. Here we compare genetic diversity of two contemporary isolated populations (Sallandse Heuvelrug, Netherlands and Lüneburger Heide, Germany) with historical samples from the same region collected within the last one hundred years. We use markers with both putatively neutral and functional variation to test whether the present small and highly fragmented populations hold lower genetic diversity compared to the former larger population. For this we applied three different types of genetic markers: nine microsatellites and 21 single nucleotide polymorphisms (SNPs), both sets which have been found to be neutral, and two functional major histocompatibility complex (MHC) genes for which there is evidence they are under selection. The contemporary small isolated populations displayed lower neutral genetic diversity compared to the corresponding historical samples. Furthermore, samples from Denmark showed that this now extinct population displayed lower genetic variation in the period immediately prior to the local extinction. Population structure was more pronounced among contemporary populations compared to historical populations for microsatellites and SNPs. This effect was not as distinct for MHC which is consistent with the possibility that MHC has been subjected to balancing selection in the past, a process which maintains genetic variation and may minimize population structure for such markers. Genetic differentiation among the present populations highlights the strong effects of population decline on the genetic structure of natural populations, which can be ultimately attributed to habitat loss following anthropogenic land use changes.
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| 3. |
- Strand, Tanja, 1978-, et al.
(författare)
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Can balancing selection on MHC loci counteract genetic drift in small fragmented populations of black grouse?
- 2012
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 2:2, s. 341-353
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Tidskriftsartikel (refereegranskat)abstract
- The ability of natural populations to adapt to new environmental conditions is crucial for their survival and partly determined by the standing genetic variation in each population. Populations with higher genetic diversity are more likely to contain individuals that are better adapted to new circumstances than populations with lower genetic diversity. Here we use both neutral and MHC markers to test whether small and highly fragmented populations hold lower genetic diversity than large ones. We use black grouse as it is distributed across Europe and found in populations with varying degrees of isolation and size. We sampled eleven different populations; five continuous, three isolated and three small and isolated. We tested patterns of genetic variation in these populations using three different types of genetic markers: nine microsatellites and 21 SNPs (Single Nucleotide Polymorphisms) which both were found to be neutral, and two functional MHC (Major Histocompatibility Complex) genes that are presumably under selection. The small isolated populations displayed significantly lower neutral genetic diversity compared to continuous populations. A similar trend, but not as pronounced, was found for genotypes at MHC class II loci. Populations were less divergent at MHC genes compared to neutral markers. Measures of genetic diversity and population genetic structure were positively correlated among microsatellites and SNPs, but none of them were correlated to MHC when comparing all populations. Our results suggest that balancing selection at MHC loci does not counteract the power of genetic drift when populations get small and fragmented.
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| 4. |
- Strand, Tanja, 1978-
(författare)
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European Black Grouse : MHC Genetic Diversity and Population Structure
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Black grouse Tetrao tetrix is a bird species composed of large, continuous as well as severely reduced and fragmented populations, making it an optimal species to investigate how genetic diversity is affected by habitat fragmentation. I have focused on genetic diversity in the Major Histocompatibility Complex (MHC) to measure the ability of the black grouse to respond to environmental changes.I partly characterized MHC class II in black grouse and found striking similarities with chicken MHC class II. I demonstrated that black grouse possess a similar compact MHC as chicken with few MHC class II B (BLB) and Y (YLB) loci. I did not find evidence of balancing selection in YLB so I concentrated further studies on BLB.I developed a PCR-based screening method for amplifying and separating expressed BLB alleles in European black grouse populations. Small fragmented populations had lost neutral genetic diversity (based on microsatellites and SNPs) compared to samples from the historical distribution and contemporary large populations. There was also a trend, albeit less pronounced, for reduced MHC diversity in these populations. Neutral markers in small isolated populations were affected by increased levels of genetic drift and were therefore genetically differentiated compared to other populations. MHC markers on the other hand, were not subjected to genetic drift to the same extent probably due a long historic process of balancing selection.Inferences of heterozygosity and evolutionary patterns as well as detailed correlations to reproductive success and diseases cannot be performed until MHC can be amplified in a locus-specific manner. Therefore, I developed a single locus sequence-based typing method for independently amplifying MHC class II B loci (BLB1 and BLB2). I found that BLB1 and BLB2 were duplicated in a common ancestor to chickens and black grouse and that these loci are subjected to homogenizing concerted evolution due to inter-genetic exchange between loci after species divergence. I could also verify that both BLB1 and BLB2 were transcribed in black grouse and under balancing selection.This collection of work has significance for future conservation of black grouse as well as research and management of zoonotic diseases.
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| 5. |
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| 6. |
- Strand, Tanja, et al.
(författare)
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Evolutionary history of black grouse major histocompatibility complex class IIB genes revealed through single locus sequence-based genotyping
- 2013
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Ingår i: BMC Genetics. - : Springer Science and Business Media LLC. - 1471-2156. ; 14, s. 29-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Gene duplications are frequently observed in the Major Histocompatibility Complex (MHC) of many species, and as a consequence loci belonging to the same MHC class are often too similar to tell apart. In birds, single locus genotyping of MHC genes has proven difficult due to concerted evolution homogenizing sequences at different loci. But studies on evolutionary history, mode of selection and heterozygosity correlations on the MHC cannot be performed before it is possible to analyse duplicated genes separately. In this study we investigate the architecture and evolution of the MHC class IIB genes in black grouse. We developed a sequence-based genotyping method for separate amplification of the two black grouse MHC class IIB genes BLB1 and BLB2. Based on this approach we are able to study differences in structure and selection between the two genes in black grouse and relate these results to the chicken MHC structure and organization. Results: Sequences were obtained from 12 individuals and separated into alleles using the software PHASE. We compared nucleotide diversity measures and employed selection tests for BLB1 and BLB2 to explore their modes of selection. Both BLB1 and BLB2 are transcribed and display classic characteristics of balancing selection as predicted for expressed MHC class IIB genes. We found evidence for both intra- and interlocus recombination or gene conversion, as well as indication for positive but differential selection at both loci. Moreover, the two loci appear to be linked. Phylogenetic analyses revealed orthology of the black grouse MHC class IIB genes to the respective BLB loci in chicken. Conclusions: The results indicate that the duplication of the BLB gene occurred before the species divergence into black grouse, chicken and pheasant. Further, we conclude that BLB1 and BLB2 in black grouse are subjected to homogenizing concerted evolution due to interlocus genetic exchange after species divergence. The loci are in linkage disequilibrium, which is in line with the theory of tightly coevolving genes within the MHC under the minimal essential MHC hypothesis. Our results support the conclusion that MHC form and function in birds derived from studies on the domesticated chicken are not artefacts of the domestication process.
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| 7. |
- Wallgren, Märtha, et al.
(författare)
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Influence of land use on the abundance of wildlife and livestock in the Kalahari, Botswana
- 2009
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Ingår i: Journal of Arid Environments. - : Elsevier BV. - 0140-1963 .- 1095-922X. ; 73:3, s. 314-321
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Tidskriftsartikel (refereegranskat)abstract
- Human land use such as pastoralism may be a key determinant of wildlife populations. We studied the influence of land use on wildlife and livestock in south-western Kalahari, Botswana, during the wet and dry seasons. We included two types of livestock areas and two types of wildlife protection areas. Wild and domestic mammals >0.2 kg were sampled by distance technique. Small mammals <0.2 kg were trapped and a vegetation survey was performed. Livestock and some medium-sized wildlife species were most abundant in livestock areas, while large-sized wildlife species were mainly restricted to wildlife areas. Most red-listed species were confined to the national park. The influence of land use on abundances changed moderately between seasons. However, cattle moved into wildlife areas during the wet season. Differences in species richness and diversity were most pronounced during the dry season. The trapping frequency of small mammals was highest in the national park. Differences in vegetation structure included sparser field layer and higher cover of an invasive shrub in livestock areas. Our study shows the importance of protected areas for many wildlife species in the Kalahari. It also shows the value of a multi-species approach for investigating the effects of land use on wildlife communities.
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| 8. |
- Esson, Carol, et al.
(författare)
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Health and zoonotic Infections of snow leopards Panthera unica in the South Gobi desert of Mongolia.
- 2019
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Ingår i: Infection Ecology & Epidemiology. - : Informa UK Limited. - 2000-8686. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Snow leopards, Panthera uncia, are a threatened apex predator, scattered across the mountains of Central and South Asia. Disease threats to wild snow leopards have not been investigated.Methods and Results: Between 2008 and 2015, twenty snow leopards in the South Gobi desert of Mongolia were captured and immobilised for health screening and radio-collaring. Blood samples and external parasites were collected for pathogen analyses using enzyme-linked immunosorbent assay (ELISA), microscopic agglutination test (MAT), and next-generation sequencing (NGS) techniques. The animals showed no clinical signs of disease, however, serum antibodies to significant zoonotic pathogens were detected. These pathogens included, Coxiella burnetii, (25% prevalence), Leptospira spp., (20%), and Toxoplasma gondii (20%). Ticks collected from snow leopards contained potentially zoonotic bacteria from the genera Bacillus, Bacteroides, Campylobacter, Coxiella, Rickettsia, Staphylococcus and Streptococcus.Conclusions: The zoonotic pathogens identified in this study, in the short-term did not appear to cause illness in the snow leopards, but have caused illness in other wild felids. Therefore, surveillance for pathogens should be implemented to monitor for potential longer- term disease impacts on this snow leopard population.
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| 9. |
- Kulma, Katarzyna, et al.
(författare)
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Immunoglobulin level and infection intensity influence how malaria-infected collared flycatchers respond to brood size manipulation
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Tidskriftsartikel (refereegranskat)abstract
- 1.The existence of a trade-off between investment in reproduction and immune function is well-established in many species. However, variation in the underlying physiological allocation strategies, which is what selection operates on, remains largely unexplored.2.We investigated how haemosporidian infection influenced stress hormone level and ability to increase parental effort in female collared flycatchers (Ficedula albicollis). We especially focused on how estimates of investment in humoral immune response and level of parasitemia influenced subsequent parental investment (i.e. offspring provisioning and offspring mass).3.To achieve these goals, we combined a brood size manipulation experiment with nested- and quantitative PCR methods to establish infection status and intensity. In addition, we quantified immunoglobulin Y (IgY) and stress protein levels.4. Malaria-infected females reared enlarged broods with lower mass but there was large variation in their response to the experiment. Only infected females with low IgY levels decreased their relative provisioning rate and there was a positive relationship between the intensity of infection and total brood mass.5. Our study implies that malaria-infected flycatchers experience a trade-off between keeping their infection at bay (i.e. low level of parasitemia) and responding to increased offspring demands (i.e. high offspring mass in enlarged broods). However, relatively immunocompetent individuals (i.e. individuals with high IgY levels) did not compromise their parental care suggesting that the main cost of raising the immune response does not lay in antibody production.
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| 10. |
- Puckett, Emily E., et al.
(författare)
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Genomic analyses reveal three independent introductions of the invasive brown rat (Rattus norvegicus) to the Faroe Islands
- 2020
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Ingår i: Heredity. - : NATURE PUBLISHING GROUP. - 0018-067X .- 1365-2540. ; 124:1, s. 15-27
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Tidskriftsartikel (refereegranskat)abstract
- Population genomics offers innovative approaches to test hypotheses related to the source and timing of introduction of invasive species. These approaches are particularly appropriate to study colonization of island ecosystems. The brown rat is a cold-hardy global invasive that has reached most of the world's island ecosystems, including even highly isolated archipelagoes such as the Faroe Islands in the North Atlantic Ocean. Historic records tell of rats rafting to the southern island of Suouroy in 1768 following a shipwreck off the coast of Scotland, then expanding across the archipelago. We investigated the demographic history of brown rats in the Faroes using 50,174 SNPs. We inferred three independent introductions of rats, including to Suouroy, the islands of Borooy and Viooy, and onto Streymoy from which they expanded to Eysturoy and Vagar. All Faroese populations showed signs of strong bottlenecks and declining effective population size. We inferred that these founder events removed low frequency alleles, the exact data needed to estimate recent demographic histories. Therefore, we were unable to accurately estimate the timing of each invasion. The difficulties with demographic inference may be applicable to other invasive species, particularly those with extreme and recent bottlenecks. We identified three invasions of brown rats to the Faroe Islands that resulted in highly differentiated populations that will be useful for future studies of life history variation and genomic adaptation.
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