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- Augustin, Jakob, 1976
(författare)
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Infidelity in Birds – Causes and Consequences of Extra-pair Paternity
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Forty years ago, more than 90% of bird species were classified as monogamous and not very exciting systems for studies of e.g. sexual selection. Since then, the discovery of extra-pair paternity (EPP) in more than 75% of surveyed monogamous bird species has made avian monogamy, and the interaction between social and genetic mating systems in general, a challenging and attractive area of research. Despite three decades of research on EPP in birds, however, many questions and controversies remain unresolved. This thesis contributes to the understanding of mechanisms and adaptive reasons, primarily from the female’s perspective, for the highly diverse frequencies of EPP in birds. First, in a population of the common redshank (Tringa totanus), a wader for which the genetic mating system has not been described previously, a surprising absence of EPP is demonstrated (I). Presumably, some female pre- or postcopulatory resistance to extra-pair fertilisations is present. The potential mechanisms and adaptive significance of this is discussed in relation to redshank ecology and behaviour. In the three following papers (II-IV), assumptions and predictions of hypothesised female benefits from EPP are addressed. In sand martins (Riparia riparia), there were no indications that extra-pair fertilisations resulted in genetic benefits (e.g. heterozygosity or ‘good genes’) (II). Paper III tests an assumption related to the genetic compatibility hypothesis, i.e. that overall heterozygosity leads to increased chick survival; this did not seem to be the case in Kentish plovers (Charadrius alexandrinus). In northern lapwings (Vanellus vanellus), the indirect benefits hypothesis is partly supported by a positive association between EPP and brood sex ratio (IV). As predicted by the differential sex allocation hypothesis, broods with extra-pair offspring contained a higher proportion of sons than broods without extrapair offspring. As for the yet unknown mechanism of sex determination in birds, an unusual case of a fertile, triploid Kentish plover female is presented and discussed with regard to the two present major hypotheses for sexdetermination (VI). Finally, as an alternative or additional interpretation of what appears to be brood sex ratio adjustment by the female, the often neglected effect of differential mortality is discussed (V).
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- Augustin, Jakob, 1976, et al.
(författare)
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No evidence of genetic benefits from extra-pair fertilisations in female sand martins (Riparia riparia)
- 2007
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Ingår i: Journal of Ornithology. - : Springer Science and Business Media LLC. - 2193-7192 .- 2193-7206. ; 148:2, s. 189-198
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Tidskriftsartikel (refereegranskat)abstract
- Genetic parentage studies of socially monogamous birds reveal a widespread prevalence of extra-pair paternity. Variation in extra-pair paternity among individuals may depend on how different individuals benefit from extra-pair fertilisations and on the opportunity to pursue extra-pair copulations. A long-term study of sand martins (Riparia riparia) in Hungary allowed us to examine patterns of extra-pair fertilisations in a large colony of over 3,000 breeding pairs with many known age individuals. We used multi-locus DNA fingerprinting to determine whether extra-pair fertilisations occur when females are paired to (1) presumably low quality mates, or (2) genetically similar or dissimilar mates, and whether extra-pair fertilisations result in offspring of higher quality. Extra-paternal young were found in 38% of 47 broods and comprised 19% of 190 offspring. Males that lost paternity did not differ significantly from others in age or body condition. Social mates of broods containing extra-pair offspring did not differ in genetic similarity from pairs without extra-pair offspring. Furthermore, there was no significant difference in body condition between extra-pair young and their maternal half-siblings. We were unable to assign paternity and therefore cannot exclude the possibility that extra-pair males differed from the within-pair males they cuckolded, in age, body condition or genetic similarity with the female. We found a positive relationship between paternity losses and breeding density, suggesting that low breeding density may constrain opportunities for seeking extra-pair copulations.
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- 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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- 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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- Kupper, C., et al.
(författare)
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Triploid plover female provides support for a role of the W chromosome in avian sex determination
- 2012
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 8:5, s. 787-789
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Tidskriftsartikel (refereegranskat)abstract
- Two models, Z Dosage and Dominant W, have been proposed to explain sex determination in birds, in which males are characterized by the presence of two Z chromosomes, and females are hemizygous with a Z and a W chromosome. According to the Z Dosage model, high dosage of a Z-linked gene triggers male development, whereas the Dominant W model postulates that a still unknown W-linked gene triggers female development. Using 33 polymorphic microsatellite markers, we describe a female triploid Kentish plover Charadrius alexandrinus identified by characteristic triallelic genotypes at 14 autosomal markers that produced viable diploid offspring. Chromatogram analysis showed that the sex chromosome composition of this female was ZZW. Together with two previously described ZZW female birds, our results suggest a prominent role for a female determining gene on the W chromosome. These results imply that avian sex determination is more dynamic and complex than currently envisioned.
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