| 21. |
- Karlsson, Maria, et al.
(författare)
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House sparrow Passer domesticus survival is not associated with MHC-I diversity, but possibly with specific MHC-I alleles
- 2015
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Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857 .- 1600-048X. ; 46:2, s. 167-174
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Tidskriftsartikel (refereegranskat)abstract
- The MHC (Major Histocompatibility Complex) plays an important role in the immune system of vertebrates. MHC genes are extremely polymorphic and this variation is considered to be maintained by selection from pathogens. We investigate whether MHC diversity (number of different alleles per individual) affects the survival and recruitment of nestling house sparrows. We hypothesize that individuals with higher MHC diversity can recognize and combat a wider range of pathogens, and therefore are more likely to survive and recruit into the breeding population. Additionally, we hypothesize that specific MHC class I alleles (MHC-I) could be associated with survival and recruitment. We screened MHC-I genotypes in 518 house sparrow chicks hatched on Lundy Island but we found no evidence for a relationship between nestling survival, post-fledging survival or recruitment success with MHC diversity. Then we investigated effects of specific MHC-I alleles in 195 individuals from a single cohort. Twenty-one MHC-I alleles were tested for relationships with nestling survival, post-fledging survival and recruitment, and we detected associations with survival for three different alleles. This pattern was, however, not different to what would be expected from random, so we could not conclude that particular MHC-I alleles are associated with survival in house sparrows on Lundy Island. Nonetheless, one of these alleles (1105) showed both a tendency for a higher probability of surviving in nestlings, and a significant association with survival in fledglings. We envision that allele 1105 could be an interesting candidate gene for testing associations with survival in house sparrows in the future.
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| 22. |
- Küpper, Clemens, et al.
(författare)
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Heterozygosity-fitness correlations of conserved microsatellite markers in Kentish plovers Charadrius alexandrinus
- 2010
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Ingår i: Molecular Ecology. - 1365-294X. ; 19:23, s. 5172-5185
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Heterozygosity-fitness correlations (HFCs) are frequently used to examine the relationship between genetic diversity and fitness. Most studies have reported positive HFCs, although there is a strong bias towards investigating HFCs in genetically impoverished populations. We investigated HFCs in a large genetically diverse breeding population of Kentish plovers Charadrius alexandrinus in southern Turkey. This small shorebird exhibits highly variable mating and care systems, and it is becoming an ecological model species to understand breeding system evolution. Using 11 conserved and six anonymous microsatellite markers, we tested whether and how heterozygosity was associated with chick survival, tarsus and body mass growth controlling for nongenetic effects (chick sex, hatching date, length of biparental care and site quality) that influence survival and growth. There was no genome-wide effect of heterozygosity on fitness, and we did not find any significant effects of heterozygosity on growth rates. However, two of the 11 conserved markers displayed an association with offspring survival: one marker showed a positive HFC, whereas the other marker showed a negative HFC. Heterozygosity at three further conserved loci showed significant interaction with nongenetic variables. In contrast, heterozygosity based on anonymous microsatellite loci was not associated with fitness or growth. Markers that were correlated with chick survival were not more likely to be located in exons or introns than other markers that lacked this association.
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| 23. |
- Küpper, Clemens, et al.
(författare)
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Kentish versus Snowy Plover: Phenotypic and Genetic Analyses of Charadrius alexandrinus Reveal Divergence of Eurasian and American Subspecies
- 2009
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Ingår i: Auk. - 0004-8038. ; 126:4, s. 839-852
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Tidskriftsartikel (refereegranskat)abstract
- Abstract.—Many shorebird species have widespread geographic distributions comprising several continents. Because shorebirds are excellent flyers and can migrate large distances, it is often unclear whether reproductive barriers between subspecies and populations from different continents exist. Kentish–Snowy Plovers (Charadrius alexandrinus) are cosmopolitan shorebirds. Whether the American and Eurasian subspecies—Snowy Plover and Kentish Plover, respectively—constitute a single species is the subject of a longstanding debate. We examined the divergence between American and Eurasian populations to reassess the current taxonomy by comparing genetic and phenotypic characters of the American subspecies C. a. nivosus and the Eurasian subspecies C. a. alexandrinus from seven populations. Genetic analyses revealed that American and Eurasian populations have strongly diverged, the Kentish Plover being more closely related to the White-fronted Plover (C. marginatus) than to the Snowy Plover. These results were consistent across all assessed nuclear markers (26 microsatellites and a partial CHD sequence) and two mitochondrial markers (ND3 and ATPase 6/8). Within subspecies, populations sampled across large geographic distances were not genetically differentiated (all Fst ≤ 0.01 and all Φst ≤ 0.06), which suggests panmixia. Snowy Plovers differed morphologically from Kentish Plovers, having significantly shorter tarsi and wings. Chick plumage and calls also may serve as diagnostic characters to distinguish Snowy and Kentish plovers, although more data are needed to quantify these differences. Our combined results suggest that the taxonomic status of C. alexandrinus needs to be revised, and we propose that Kentish Plover and Snowy Plover be recognized as separate species: C. alexandrinus and C. nivosus, respectively.
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| 24. |
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| 25. |
- Meziane, El Kahina, et al.
(författare)
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Bi-Functional Chicken Immunoglobulin-Like Receptors With a Single Extracellular Domain (ChIR-AB1): Potential Framework Genes Among a Relatively Stable Number of Genes Per Haplotype
- 2019
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Ingår i: Frontiers in Immunology. - : FRONTIERS MEDIA SA. - 1664-3224. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- The leukocyte receptor complex (LRC) in humans encodes many receptors with immunoglobulin-like (Ig-like) extracellular domains, including the killer Ig-like receptors (KIRs) expressed on natural killer (NK) cells among others, the leukocyte Ig-like receptors (LILRs) expressed on myeloid and B cells, and an Fc receptor (FcR), all of which have important roles in the immune response. These highly-related genes encode activating receptors with positively-charged residues in the transmembrane region, inhibitory receptors with immuno-tyrosine based motifs (ITIMs) in the cytoplasmic tail, and bi-functional receptors with both. The related chicken Ig-like receptors (ChIRs) are almost all found together on a microchromosome, with over 100 activating (A), inhibitory (B), and bi-functional (AB) genes, bearing either one or two extracellular Ig-like domains, interspersed over 500-1,000 kB in the genome of an individual chicken. Sequencing studies have suggested rapid divergence and little overlap between ChIR haplotypes, so we wished to begin to understand their genetics. We chose to use a hybridization technique, reference strand-mediated conformational analysis (RSCA), to examine the ChIR-AB1 family, with a moderate number of genes dispersed across the microchromosome. Using fluorescently-labeled references (FLR), we found that RSCA and sequencing of ChIR-AB1 extracellular exon gave two groups of peaks with mobility correlated with sequence relationship to the FLR. We used this system to examine widely-used and well-characterized experimental chicken lines, finding only one or a few simple ChIR haplotypes for each line, with similar numbers of peaks overall. We found much more complicated patterns from a broiler line from a commercial breeder and a flock of red junglefowl, but trios of parents and offspring from another commercial chicken line show that the complicated patterns are due to heterozygosity, indicating a relatively stable number of peaks within haplotypes of these birds. Some ChIR-AB1 peaks were found in all individuals from the commercial lines, and some of these were shared with red junglefowl and the experimental lines derived originally from egg-laying chickens. Overall, this analysis suggests that there are some simple features underlying the apparent complexity of the ChIR locus.
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| 26. |
- Raj Pant, Sara, et al.
(författare)
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The contribution of extra-pair paternity to the variation in lifetime and age-specific male reproductive success in a socially monogamous species
- 2022
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Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 76:5, s. 915-930
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Tidskriftsartikel (refereegranskat)abstract
- In socially monogamous species, extra-pair paternity (EPP) is predicted to increase variance in male reproductive success (RS) beyond that resulting from genetic monogamy, thus, increasing the “opportunity for selection” (maximum strength of selection that can act on traits). This prediction is challenging to investigate in wild populations because lifetime reproduction data are often incomplete. Moreover, age-specific variances in reproduction have been rarely quantified. We analyzed 21 years of near-complete social and genetic reproduction data from an insular population of Seychelles warblers (Acrocephalus sechellensis). We quantified EPP's contribution to lifetime and age-specific opportunities for selection in males. We compared the variance in male genetic RS vs social (“apparent”) RS (RSap) to assess if EPP increased the opportunity for selection over that resulting from genetic monogamy. Despite not causing a statistically significant excess (19%) of the former over the latter, EPP contributed substantially (27%) to the variance in lifetime RS, similarly to within-pair paternity (WPP, 39%) and to the positive WPP-EPP covariance (34%). Partitioning the opportunity for selection into age-specific (co)variance components, showed that EPP also provided a substantial contribution at most ages, varying with age. Therefore, despite possibly not playing the main role in shaping sexual selection in Seychelles warblers, EPP provided a substantial contribution to the lifetime and age-specific opportunity for selection, which can influence evolutionary processes in age-structured populations.
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| 27. |
- Razali, Haslina, et al.
(författare)
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A quantitative and qualitative comparison of illumina MiSeq and 454 amplicon sequencing for genotyping the highly polymorphic major histocompatibility complex (MHC) in a non‑model species
- 2017
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Ingår i: BMC Research Notes. - : Springer Science and Business Media LLC. - 1756-0500. ; 10:1, s. 346-356
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Tidskriftsartikel (refereegranskat)abstract
- Background: High-throughput sequencing enables high-resolution genotyping of extremely duplicated genes.454 amplicon sequencing (454) has become the standard technique for genotyping the major histocompatibilitycomplex (MHC) genes in non-model organisms. However, illumina MiSeq amplicon sequencing (MiSeq), which offersa much higher read depth, is now superseding 454. The aim of this study was to quantitatively and qualitativelyevaluate the performance of MiSeq in relation to 454 for genotyping MHC class I alleles using a house sparrow (Passerdomesticus) dataset with pedigree information. House sparrows provide a good study system for this comparison astheir MHC class I genes have been studied previously and, consequently, we had prior expectations concerning thenumber of alleles per individual.Results: We found that 454 and MiSeq performed equally well in genotyping amplicons with low diversity, i.e. ampliconsfrom individuals that had fewer than 6 alleles. Although there was a higher rate of failure in the 454 dataset inresolving amplicons with higher diversity (6–9 alleles), the same genotypes were identified by both 454 and MiSeq in98% of cases.Conclusions: We conclude that low diversity amplicons are equally well genotyped using either 454 or MiSeq,but the higher coverage afforded by MiSeq can lead to this approach outperforming 454 in amplicons with higherdiversity.
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| 28. |
- Sodergren, Erica, et al.
(författare)
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The genome of the sea urchin Strongylocentrotus purpuratus.
- 2006
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 314:5801, s. 941-52
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Tidskriftsartikel (refereegranskat)abstract
- We report the sequence and analysis of the 814-megabase genome of the sea urchin Strongylocentrotus purpuratus, a model for developmental and systems biology. The sequencing strategy combined whole-genome shotgun and bacterial artificial chromosome (BAC) sequences. This use of BAC clones, aided by a pooling strategy, overcame difficulties associated with high heterozygosity of the genome. The genome encodes about 23,300 genes, including many previously thought to be vertebrate innovations or known only outside the deuterostomes. This echinoderm genome provides an evolutionary outgroup for the chordates and yields insights into the evolution of deuterostomes.
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| 29. |
- Teplitsky, Celine, et al.
(författare)
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Assessing Multivariate Constraints to Evolution across Ten Long-Term Avian Studies
- 2014
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:3, s. e90444-
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Tidskriftsartikel (refereegranskat)abstract
- Background: In a rapidly changing world, it is of fundamental importance to understand processes constraining or facilitating adaptation through microevolution. As different traits of an organism covary, genetic correlations are expected to affect evolutionary trajectories. However, only limited empirical data are available. Methodology/Principal Findings: We investigate the extent to which multivariate constraints affect the rate of adaptation, focusing on four morphological traits often shown to harbour large amounts of genetic variance and considered to be subject to limited evolutionary constraints. Our data set includes unique long-term data for seven bird species and a total of 10 populations. We estimate population-specific matrices of genetic correlations and multivariate selection coefficients to predict evolutionary responses to selection. Using Bayesian methods that facilitate the propagation of errors in estimates, we compare (1) the rate of adaptation based on predicted response to selection when including genetic correlations with predictions from models where these genetic correlations were set to zero and (2) the multivariate evolvability in the direction of current selection to the average evolvability in random directions of the phenotypic space. We show that genetic correlations on average decrease the predicted rate of adaptation by 28%. Multivariate evolvability in the direction of current selection was systematically lower than average evolvability in random directions of space. These significant reductions in the rate of adaptation and reduced evolvability were due to a general nonalignment of selection and genetic variance, notably orthogonality of directional selection with the size axis along which most (60%) of the genetic variance is found. Conclusions: These results suggest that genetic correlations can impose significant constraints on the evolution of avian morphology in wild populations. This could have important impacts on evolutionary dynamics and hence population persistence in the face of rapid environmental change.
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| 30. |
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