Cell‐mediated immunity and multi‐locus heterozygosity in bluethroat nestlings

Fossøy, Frode; Johnsen, Arild; Lifjeld, Jan T.

doi:10.1111/j.1420-9101.2009.01790.x

Cited by 14 publications

(21 citation statements)

References 55 publications

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“…; Fossoy et al. ). However, it has recently been put forward that the existence of HFCs among full‐siblings should be interpreted with care, as full‐siblings will vary in the proportion of the genome, which is identical by descent due to chance events during Mendelian segregation (Franklin ; Forstmeier et al.…”

Section: Discussionmentioning

confidence: 97%

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Heterozygosity is linked to the costs of immunity in nestling great tits (Parus major)

Voegeli

Saladin

Wegmann

et al. 2013

Ecology and Evolution

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There is growing evidence that heterozygosity–fitness correlations (HFCs) are more pronounced under harsh conditions. Empirical evidence suggests a mediating effect of parasite infestation on the occurrence of HFCs. Parasites have the potential to mediate HFCs not only by generally causing high stress levels but also by inducing resource allocation tradeoffs between the necessary investments in immunity and other costly functions. To investigate the relative importance of these two mechanisms, we manipulated growth conditions of great tit nestlings by brood size manipulation, which modifies nestling competition, and simultaneously infested broods with ectoparasites. We investigated under which treatment conditions HFCs arise and, second, whether heterozygosity is linked to tradeoff decisions between immunity and growth. We classified microsatellites as neutral or presumed functional and analyzed these effects separately. Neutral heterozygosity was positively related to the immune response to a novel antigen in parasite-free nests, but not in infested nests. For nestlings with lower heterozygosity levels, the investments in immunity under parasite pressure came at the expenses of reduced feather growth, survival, and female body condition. Functional heterozygosity was negatively related to nestling immune response regardless of the growth conditions. These contrasting effects of functional and neutral markers might indicate different underlying mechanisms causing the HFCs. Our results confirm the importance of considering marker functionality in HFC studies and indicate that parasites mediate HFCs by influencing the costs of immune defense rather than by a general increase in environmental harshness levels.

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Section: Discussionmentioning

confidence: 97%

“…; Fossoy et al. ), individual heterozygosity may influence the costs derived from mounting an immune response.…”

Section: Introductionmentioning

confidence: 99%

Heterozygosity is linked to the costs of immunity in nestling great tits (Parus major)

Voegeli

Saladin

Wegmann

et al. 2013

Ecology and Evolution

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“…As fullsiblings share their ancestry and inbreeding history, HFCs within full-sibling are commonly interpreted as evidence for local effects (Hansson et al 2001;Da Silva et al 2006;Fossøy et al 2009). However, it has recently been put forward that the existence of HFCs among full-siblings should be interpreted with care, as full-siblings will vary in the proportion of the genome, which is identical by descent due to chance events during Mendelian segregation (Forstmeier et al 2012; but see Hansson and Westerberg 2008).…”

Section: Discussionmentioning

confidence: 99%

Heterozygosity–fitness correlations in blue tit nestlings (Cyanistis caeruleus) under contrasting rearing conditions

et al. 2017

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Understanding the relation between genetic variation and fitness remains a key question in evolutionary biology. Although heterozygosity has been reported to correlate with many fitness-related traits, the strength of the heterozygosity-fitness correlations (HFCs) is usually weak and it is still difficult to assess the generality of these associations in natural populations. It has been suggested that HFCs may become meaningful only under particular environmental conditions. Moreover, existing evidence suggests that HFCs may also differ between sexes. The aim of this study was to investigate correlations between heterozygosity in neutral markers (microsatellites) and fitness-related traits in a natural population of blue tits (Cyanistes caeruleus). Additionally, we tested whether sex and environmental conditions may influence the magnitude and direction of HFCs. We found a positive relationship between heterozygosity and body mass of 14 days posthatching nestlings, but only among females. Our results suggest that the correlation between heterozygosity and nestling body mass observed among female offspring could be attributed to within-brood effects. We failed to find any evidence that environmental conditions as simulated by brood size manipulation affect HFCs.

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“…The persistence of these populations and the maintenance of their genetic diversity indicate a capacity to recover from small population size following fire. Set against this positive, our survey of microsatellite variation suggests the possibility that both central populations have been affected by a recent genetic bottleneck, although the apparent excess heterozygosity (relative to the expectation of mutation-drift equilibrium) may be explained by some aspect of the mating system of D. brachypterus, particularly if individuals display positive assortative mating (e.g., Bitton et al 2008) or if heterozygotes have a selective advantage (Hansson et al 2001;MacDougall-Shackleton et al 2005;Fossoy et al 2009). Nevertheless, D. brachypterus is fire sensitive, and fire-history is thought to be a major determinant of local population size (Baker 2000).…”

Section: Discussionmentioning

confidence: 90%

Population genetic structure of the endangered Eastern Bristlebird, Dasyornis brachypterus; implications for conservation

2011

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For species that are habitat specialists or sedentary, population fragmentation may lead to genetic divergence between populations and reduced genetic diversity within populations, with frequent inbreeding. Hundreds of kilometres separate three geographical regions in which small populations of the endangered Eastern Bristlebird, Dasyornis brachypterus, a small, grounddwelling passerine that occurs in fire-prone bushland in eastern Australia, are currently found. Here, we use mitochondrial and microsatellite DNA markers to: (i) assess the sub-specific taxonomy designated to northern range-edge, and central and southern range-edge D. brachypterus, respectively, and (ii) assess levels of standing genetic variation and the degree of genetic subdivision of remnant populations. The phylogenetic relationship among mtDNA haplotypes and their spatial distribution did not support the recognised subspecies boundaries. Populations in different regions were highly genetically differentiated, but in addition, the two largest, neighboring populations (located within the central region and separated by *50 km) were moderately differentiated, and thus are likely closed to migration (microsatellites, F ST = 0.06; mtDNA, F ST = 0.12, H ST = 0.08). Birds within these two populations were genotypically diverse and apparently randomly mating. A long-term plan for the conservation of D. brachypterus's genetic diversity should consider individual populations as separate management units. Moreover, managers should avoid actively mixing birds from different populations or regions, to conserve the genetic integrity of local populations and avoid outbreeding depression, should further translocations be used as a recovery tool for this species.

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Cell‐mediated immunity and multi‐locus heterozygosity in bluethroat nestlings

Cited by 14 publications

References 55 publications

Heterozygosity is linked to the costs of immunity in nestling great tits (Parus major)

Heterozygosity is linked to the costs of immunity in nestling great tits (Parus major)

Heterozygosity–fitness correlations in blue tit nestlings (Cyanistis caeruleus) under contrasting rearing conditions

Population genetic structure of the endangered Eastern Bristlebird, Dasyornis brachypterus; implications for conservation

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