Psychometric properties of the Swedish version of the Parenting Concerns Questionnaire in parents with cancer.

BACKGROUND AND PURPOSE: Parenting concerns can be a major source of distress for patients with cancer who are parents of dependent children; however, these are often not addressed in health care. The Parenting Concerns Questionnaire (PCQ) is an instrument designed to assess parents' worries about the impact of cancer on their children and their ability to parent during this time. The Swedish version of the PCQ has, however, not been evaluated. This study therefore aimed to examine the psychometric properties of the PCQ in a sample of Swedish parents with cancer. MATERIAL AND METHODS: A sample of 336 patients with cancer having dependent children (≤18 years) were included in a cross-sectional web-based survey. Participants completed questionnaires assessing parenting concerns, depression, anxiety, and stress symptoms (DASS); self-efficacy, family functioning (FAD-GF); and sociodemographic and clinical characteristics. Descriptive analyses, as well as reliability and validity analyses, were conducted followed by a confirmatory factor analysis of the factor structure proposed by the authors of the original version of the PCQ. RESULTS: The majority were mothers (94.9%) with breast cancer (66.4%) aged 40-50 years (59.5%). The results showed evidence for convergent, criterion, and known group's validity, but the original three-factor structure of the PCQ was not fully supported by confirmatory factor analysis. INTERPRETATION: Evaluating parenting concerns may be an important step towards identifying patients who could benefit from targeted psychosocial interventions. However, the PCQ may require some further refinement to fully capture the breadth of parenting concerns in parents with cancer in different settings.

Parenting under pressure: a cross-sectional questionnaire study of psychological distress, parenting concerns, self-efficacy, and emotion regulation in parents with cancer.

BACKGROUND AND PURPOSE: As many as one in four adults with cancer have children under 18 years. Balancing parenting and cancer is challenging and can be a source of psychological distress. This study aimed to examine psychological distress in parents with cancer and its associations with parenting concerns, self-efficacy, and emotion regulation. MATERIALS AND METHODS: This was a cross-sectional questionnaire study of 406 parents (aged 25-60 years) diagnosed with cancer within the last 5 years, with at least one dependent child (≤ 18 years). Parents completed questionnaires on psychological distress (DASS-21), parenting concerns (PCQ), self-efficacy (GSE), emotion regulation (ERQ), mental and physical health, and sociodemographics. Data were analysed using multiple logistic regressions on depression (yes/no), anxiety (yes/no), and stress (yes/no). RESULTS: Higher parenting concerns were associated with greater odds of depression (OR = 2.33, 95% CI: 1.64-3.31), anxiety (OR = 2.30, 95% CI: 1.64-3.20), and stress (OR = 3.21, 95% CI: 2.20-4.69) when adjusting for health and sociodemographic factors. Poorer self-efficacy was associated with increased odds of anxiety (OR = 0.94, 95% CI: 0.89-0.99, p < 0.05), whereas lower use of cognitive reappraisal and higher use of expressive suppression increased the odds of depression (OR = 0.76, 95% CI: 0.59-0.98 | OR = 1.46, 95% CI: 1.18-1.80). INTERPRETATION: The findings highlight the complexity of parental well-being in relation to parenthood and cancer, stressing the need for interventions that address relevant psychological factors to improve overall mental health in this population.

The Complexity of Being a Parent in the Hospital and a Patient at Home: A Qualitative Study on Parenting Concerns and Challenges Among Parents With Cancer.

BACKGROUND: Parents given a diagnosis of cancer must balance the demands of their illness and caregiving responsibilities. This can result in parental stress and have a negative impact on the well-being of the whole family. A greater understanding of the experiences of parents with cancer is necessary to provide adequate support. OBJECTIVE: The aim of this study was to explore parenting concerns and challenges among parents with cancer who were caring for dependent children younger than 18 years. METHODS: Semistructured interviews were carried out with 22 parents with cancer. Interviews were audio-recorded, transcribed, and analyzed using thematic analysis. RESULTS: Parental concerns and challenges affected parents in their parental role and their everyday family life. Three overarching themes described the struggles in balancing life as a parent and as a patient: navigating dual roles as a parent with cancer, impact of cancer on parenting, and impact on family life. Parents' primary focus was on their children's well-being, and they struggled to manage their own expectations of parenting and the demands on their role in the family. CONCLUSION: The results highlight the complexity of being a parent with cancer while caring for dependent children. To support parents during the cancer journey, it is important to understand the consequences of their illness on their parental role and the family. IMPLICATIONS FOR PRACTICE: Supporting parents to feel secure in their parental role and providing support to them during their cancer journey should be integrated into routine cancer care, where parenting concerns and challenges are addressed.

Psychosocial interventions targeting parenting distress among parents with cancer - A systematic review and narrative synthesis of available interventions.

BACKGROUND: Balancing having cancer and parenting a major stressor, and may result in parenting distress, negatively affecting the whole family. To provide adequate support, knowledge of existing psychosocial interventions are crucial to guide future interventions. This study aimed to describe available psychosocial interventions for parents with cancer and dependent children (<18 years). METHOD: We conducted a systematic review, and four databases were searched from January 2000 to March 2023. RESULTS: Thirty studies were included, reporting on 22 psychosocial interventions for parents with cancer. They aimed to improve different aspects of parenting distress, and included psychoeducation and communication strategies. Interventions were beneficial to and acceptable among parents, but only a few had been evaluated. The study quality was, overall, assessed as moderate. CONCLUSIONS: The results of this review highlight the diversity of available psychosocial interventions for parents with cancer and the outcomes on parenting distress, as well as methodological challenges.

MHC class II genotype-by-pathogen genotype interaction for infection prevalence in a natural rodent-Borrelia system.

MHC genes are extraordinarily polymorphic in most taxa. Host-pathogen coevolution driven by negative frequency-dependent selection (NFDS) is one of the main hypotheses for the maintenance of such immunogenetic variation. Here, we test a critical but rarely tested assumption of this hypothesis-that MHC alleles affect resistance/susceptibility to a pathogen in a strain-specific way, that is, there is a host genotype-by-pathogen genotype interaction. In a field study of bank voles naturally infected with the tick-transmitted bacterium Borrelia afzelii, we tested for MHC class II (DQB) genotype-by-B. afzelii strain interactions for infection prevalence between 10 DQB alleles and seven strains. One allele (DQB*37) showed an interaction, such that voles carrying DQB*37 had higher prevalence of two strains and lower prevalence of one strain than individuals without the allele. These findings were corroborated by analyses of strain composition of infections, which revealed an effect of DQB*37 in the form of lower ß diversity among infections in voles carrying the allele. Taken together, these results provide rare support at the molecular genetic level for a key assumption of models of antagonistic coevolution through NFDS.

Implementing School-Based Mental Health Services: A Scoping Review of the Literature Summarizing the Factors That Affect Implementation.

BACKGROUND: Mental illness in children and youths has become an increasing problem. School-based mental health services (SBMHS) are an attempt to increase accessibility to mental health services. The effects of these services seem positive, with some mixed results. To date, little is known about the implementation process of SBMHS. Therefore, this scoping review synthesizes the literature on factors that affect the implementation of SBMHS. METHODS: A scoping review based on four stages: (a) identifying relevant studies; (b) study selection; (c) charting the data; and (d) collating, summarizing, and reporting the results was performed. From the searches (4414 citations), 360 were include in the full-text screen and 38 in the review. RESULTS: Implementation-related factors were found in all five domains of the Consolidated Framework for Implementation Research. However, certain subfactors were mentioned more often (e.g., the adaptability of the programs, communication, or engagement of key stakeholders). CONCLUSIONS: Even though SBMHS differed in their goals and way they were conducted, certain common implementation factors were highlighted more frequently. To minimize the challenges associated with these types of interventions, learning about the implementation of SBMHS and using this knowledge in practice when introducing SBMHS is essential to achieving the best possible effects with SMBHSs.

The genomic architecture of the passerine MHC region: High repeat content and contrasting evolutionary histories of single copy and tandemly duplicated MHC genes.

The major histocompatibility complex (MHC) is of central importance to the immune system, and an optimal MHC diversity is believed to maximize pathogen elimination. Birds show substantial variation in MHC diversity, ranging from few genes in most bird orders to very many genes in passerines. Our understanding of the evolutionary trajectories of the MHC in passerines is hampered by lack of data on genomic organization. Therefore, we assembled and annotated the MHC genomic region of the great reed warbler (Acrocephalus arundinaceus), using long-read sequencing and optical mapping. The MHC region is large (>5.5 Mb), characterized by structural changes compared to hitherto investigated bird orders and shows higher repeat content than the genome average. These features were supported by analyses in three additional passerines. MHC genes in passerines are found in two different chromosomal arrangements, either as single copy MHC genes located among non-MHC genes, or as tandemly duplicated tightly linked MHC genes. Some single copy MHC genes are old and putative orthologues among species. In contrast tandemly duplicated MHC genes are monophyletic within species and have evolved by simultaneous gene duplication of several MHC genes. Structural differences in the MHC genomic region among bird orders seem substantial compared to mammals and have possibly been fuelled by clade-specific immune system adaptations. Our study provides methodological guidance in characterizing complex genomic regions, constitutes a resource for MHC research in birds, and calls for a revision of the general belief that avian MHC has a conserved gene order and small size compared to mammals.

Avian Neo-Sex Chromosomes Reveal Dynamics of Recombination Suppression and W Degeneration.

How the avian sex chromosomes first evolved from autosomes remains elusive as 100 million years (My) of divergence and degeneration obscure their evolutionary history. The Sylvioidea group of songbirds is interesting for understanding avian sex chromosome evolution because a chromosome fusion event ∼24 Ma formed "neo-sex chromosomes" consisting of an added (new) and an ancestral (old) part. Here, we report the complete female genome (ZW) of one Sylvioidea species, the great reed warbler (Acrocephalus arundinaceus). Our long-read assembly shows that the added region has been translocated to both Z and W, and whereas the added-Z has retained its gene order the added-W part has been heavily rearranged. Phylogenetic analyses show that recombination between the homologous added-Z and -W regions continued after the fusion event, and that recombination suppression across this region took several million years to be completed. Moreover, recombination suppression was initiated across multiple positions over the added-Z, which is not consistent with a simple linear progression starting from the fusion point. As expected following recombination suppression, the added-W show signs of degeneration including repeat accumulation and gene loss. Finally, we present evidence for nonrandom maintenance of slowly evolving and dosage-sensitive genes on both ancestral- and added-W, a process causing correlated evolution among orthologous genes across broad taxonomic groups, regardless of sex linkage.

Early-life gut dysbiosis linked to juvenile mortality in ostriches.

BACKGROUND: Imbalances in the gut microbial community (dysbiosis) of vertebrates have been associated with several gastrointestinal and autoimmune diseases. However, it is unclear which taxa are associated with gut dysbiosis, and if particular gut regions or specific time periods during ontogeny are more susceptible. We also know very little of this process in non-model organisms, despite an increasing realization of the general importance of gut microbiota for health. METHODS: Here, we examine the changes that occur in the microbiome during dysbiosis in different parts of the gastrointestinal tract in a long-lived bird with high juvenile mortality, the ostrich (Struthio camelus). We evaluated the 16S rRNA gene composition of the ileum, cecum, and colon of 68 individuals that died of suspected enterocolitis during the first 3 months of life (diseased individuals), and of 50 healthy individuals that were euthanized as age-matched controls. We combined these data with longitudinal environmental and fecal sampling to identify potential sources of pathogenic bacteria and to unravel at which stage of development dysbiosis-associated bacteria emerge. RESULTS: Diseased individuals had drastically lower microbial alpha diversity and differed substantially in their microbial beta diversity from control individuals in all three regions of the gastrointestinal tract. The clear relationship between low diversity and disease was consistent across all ages in the ileum, but decreased with age in the cecum and colon. Several taxa were associated with mortality (Enterobacteriaceae, Peptostreptococcaceae, Porphyromonadaceae, Clostridium), while others were associated with health (Lachnospiraceae, Ruminococcaceae, Erysipelotrichaceae, Turicibacter, Roseburia). Environmental samples showed no evidence of dysbiosis-associated bacteria being present in either the food, water, or soil substrate. Instead, the repeated fecal sampling showed that pathobionts were already present shortly after hatching and proliferated in individuals with low microbial diversity, resulting in high mortality several weeks later. CONCLUSIONS: Identifying the origins of pathobionts in neonates and the factors that subsequently influence the establishment of diverse gut microbiota may be key to understanding dysbiosis and host development. Video Abstract.

Odorant receptor phylogeny confirms conserved channels for sex pheromone and host plant signals in tortricid moths.

The search for mates and food is mediated by volatile chemicals. Insects sense food odorants and sex pheromones through odorant receptors (ORs) and pheromone receptors (PRs), which are expressed in olfactory sensory neurons. Molecular phylogenetics of ORs, informed by behavioral and functional data, generates sound hypotheses for the identification of semiochemicals driving olfactory behavior. Studying orthologous receptors and their ligands across taxa affords insights into the role of chemical communication in reproductive isolation and phylogenetic divergence. The female sex pheromone of green budworm moth Hedya nubiferana (Lepidoptera, Totricidae) is a blend of two unsaturated acetates, only a blend of both elicits male attraction. Females produce in addition codlemone, which is the sex pheromone of another tortricid, codling moth Cydia pomonella. Codlemone also attracts green budworm moth males. Concomitantly, green budworm and codling moth males are attracted to the host plant volatile pear ester. A congruent behavioral response to the same pheromone and plant volatile in two tortricid species suggests co-occurrence of dedicated olfactory channels. In codling moth, one PR is tuned to both compounds, the sex pheromone codlemone and the plant volatile pear ester. Our phylogenetic analysis finds that green budworm moth expresses an orthologous PR gene. Shared ancestry, and high levels of amino acid identity and sequence similarity, in codling and green budworm moth PRs offer an explanation for parallel attraction of both species to the same compounds. A conserved olfactory channel for a sex pheromone and a host plant volatile substantiates the alliance of social and habitat signals in insect chemical communication. Field attraction assays confirm that in silico investigations of ORs afford powerful predictions for an efficient identification of behavior-modifying semiochemicals, for an improved understanding of the mechanisms of host plant attraction in insect herbivores and for the further development of sustainable insect control.

Major shifts in gut microbiota during development and its relationship to growth in ostriches.

The development of gut microbiota during ontogeny is emerging as an important process influencing physiology, immunity and fitness in vertebrates. However, knowledge of how bacteria colonize the juvenile gut, how this is influenced by changes in the diversity of gut bacteria and to what extent this influences host fitness, particularly in nonmodel organisms, is lacking. Here we used 16S rRNA gene sequencing to describe the successional development of the faecal microbiome in ostriches (Struthio camelus, n = 66, repeatedly sampled) over the first 3 months of life and its relationship to growth. We found a gradual increase in microbial diversity with age that involved multiple colonization and extinction events and a major taxonomic shift in bacteria that coincided with the cessation of yolk absorption. Comparisons with the microbiota of adults (n = 5) revealed that the chicks became more similar in their microbial diversity and composition to adults as they aged. There was a five-fold difference in juvenile growth during development, and growth during the first week of age was strongly positively correlated with the abundance of the genus Bacteroides and negatively correlated with Akkermansia. After the first week, the abundances of six phylogenetically diverse families (Peptococcaceae, S24-7, Verrucomicrobiae, Anaeroplasmataceae, Streptococcaceae, Methanobacteriaceae) were associated with subsequent reductions in chick growth in an age-specific and transient manner. These results have broad implications for our understanding of the development of gut microbiota and its associations with animal growth.

Owls lack UV-sensitive cone opsin and red oil droplets, but see UV light at night: Retinal transcriptomes and ocular media transmittance.

Most diurnal birds have cone-dominated retinae and tetrachromatic colour vision based on ultra-violet/violet-sensitive UV/V cones expressing short wavelength-sensitive opsin 1 (SWS1), S cones expressing short wavelength-sensitive opsin 2 (SWS2), M cones expressing medium wavelength-sensitive opsin (RH2) and L cones expressing long wavelength-sensitive opsin (LWS). Double cones (D) express LWS but do not contribute to colour vision. Each cone is equipped with an oil droplet, transparent in UV/V cones, but pigmented by carotenoids: galloxanthin in S, zeaxanthin in M, astaxanthin in L and a mixture in D cones. Owls (Strigiformes) are crepuscular or nocturnal birds with rod-dominated retinae and optical adaptations for high sensitivity. For eight species, the absence of functional SWS1 opsin has recently been documented, functional RH2 opsin was absent in three of these. Here we confirm the absence of SWS1 transcripts for the Long-eared owl (Asio otus) and demonstrate its absence for the Short-eared owl (Asio flammeus), Tawny owl (Strix aluco) and Boreal owl (Aegolius funereus). All four species had transcripts of RH2, albeit with low expression. All four species express all enzymes needed to produce galloxanthin, but lack CYP2J19 expression required to produce astaxanthin from dietary precursors. We also present ocular media transmittance of the Eurasian eagle owl (Bubo bubo) and Short-eared owl and predict spectral sensitivities of all photoreceptors of the Tawny owl. We conclude that owls, despite lacking UV/V cones, can detect UV light. This increases the sensitivity of their rod vision allowing them, for instance, to see UV-reflecting feathers as brighter signals at night.

Plumage microbiota covaries with the major histocompatibility complex in blue petrels.

To increase fitness, a wide range of vertebrates preferentially mate with partners that are dissimilar at the major histocompatibility complex (MHC) or that have high MHC diversity. Although MHC often can be assessed through olfactory cues, the mechanism by which MHC genes influence odour remains largely unclear. MHC class IIB molecules, which enable recognition and elimination of extracellular bacteria, have been suggested to influence odour indirectly by shaping odour-producing microbiota, i.e. bacterial communities. However, there is little evidence of the predicted covariation between an animal's MHC genotype and its bacterial communities in scent-producing body surfaces. Here, using high-throughput sequencing, we tested the covariation between MHC class IIB genotypes and feather microbiota in the blue petrel (Halobaena caerulea), a seabird with highly developed olfaction that has been suggested to rely on oduor cues during an MHC-based mate choice. First, we show that individuals with similar MHC class IIB profiles also have similar bacterial assemblages in their feathers. Then, we show that individuals with high MHC diversity have less diverse feather microbiota and also a reduced abundance of a bacterium of the genus Arsenophonus, a genus in which some species are symbionts of avian ectoparasites. Our results, showing that feather microbiota covary with MHC, are consistent with the hypothesis that individual MHC genotype may shape the semiochemical-producing microbiota in birds.

Contrasting results from GWAS and QTL mapping on wing length in great reed warblers.

A major goal in evolutionary biology is to understand the genetic basis of adaptive traits. In migratory birds, wing morphology is such a trait. Our previous work on the great reed warbler (Acrocephalus arundinaceus) shows that wing length is highly heritable and under sexually antagonistic selection. Moreover, a quantitative trait locus (QTL) mapping analysis detected a pronounced QTL for wing length on chromosome 2, suggesting that wing morphology is partly controlled by genes with large effects. Here, we re-evaluate the genetic basis of wing length in great reed warblers using a genomewide association study (GWAS) approach based on restriction site-associated DNA sequencing (RADseq) data. We use GWAS models that account for relatedness between individuals and include covariates (sex, age and tarsus length). The resulting association landscape was flat with no peaks on chromosome 2 or elsewhere, which is in line with expectations for polygenic traits. Analysis of the distribution of p-values did not reveal biases, and the inflation factor was low. Effect sizes were however not uniformly distributed on some chromosomes, and the Z chromosome had weaker associations than autosomes. The level of linkage disequilibrium (LD) in the population decayed to background levels within c. 1 kbp. There could be several reasons to why our QTL study and GWAS gave contrasting results including differences in how associations are modelled (cosegregation in pedigree vs. LD associations), how covariates are accounted for in the models, type of marker used (multi- vs. biallelic), difference in power or a combination of these. Our study highlights that the genetic architecture even of highly heritable traits is difficult to characterize in wild populations.

Measuring the gut microbiome in birds: Comparison of faecal and cloacal sampling.

The gut microbiomes of birds and other animals are increasingly being studied in ecological and evolutionary contexts. Numerous studies on birds and reptiles have made inferences about gut microbiota using cloacal sampling; however, it is not known whether the bacterial community of the cloaca provides an accurate representation of the gut microbiome. We examined the accuracy with which cloacal swabs and faecal samples measure the microbiota in three different parts of the gastrointestinal tract (ileum, caecum, and colon) using a case study on juvenile ostriches, Struthio camelus, and high-throughput 16S rRNA sequencing. We found that faeces were significantly better than cloacal swabs in representing the bacterial community of the colon. Cloacal samples had a higher abundance of Gammaproteobacteria and fewer Clostridia relative to the gut and faecal samples. However, both faecal and cloacal samples were poor representatives of the microbial communities in the caecum and ileum. Furthermore, the accuracy of each sampling method in measuring the abundance of different bacterial taxa was highly variable: Bacteroidetes was the most highly correlated phylum between all three gut sections and both methods, whereas Actinobacteria, for example, was only strongly correlated between faecal and colon samples. Based on our results, we recommend sampling faeces, whenever possible, as this sample type provides the most accurate assessment of the colon microbiome. The fact that neither sampling technique accurately portrayed the bacterial community of the ileum nor the caecum illustrates the difficulty in noninvasively monitoring gut bacteria located further up in the gastrointestinal tract. These results have important implications for the interpretation of avian gut microbiome studies.

Direct PCR Offers a Fast and Reliable Alternative to Conventional DNA Isolation Methods for Gut Microbiomes.

The gut microbiome of animals is emerging as an important factor influencing ecological and evolutionary processes. A major bottleneck in obtaining microbiome data from large numbers of samples is the time-consuming laboratory procedures required, specifically the isolation of DNA and generation of amplicon libraries. Recently, direct PCR kits have been developed that circumvent conventional DNA extraction steps, thereby streamlining the laboratory process by reducing preparation time and costs. However, the reliability and efficacy of direct PCR for measuring host microbiomes have not yet been investigated other than in humans with 454 sequencing. Here, we conduct a comprehensive evaluation of the microbial communities obtained with direct PCR and the widely used Mo Bio PowerSoil DNA extraction kit in five distinct gut sample types (ileum, cecum, colon, feces, and cloaca) from 20 juvenile ostriches, using 16S rRNA Illumina MiSeq sequencing. We found that direct PCR was highly comparable over a range of measures to the DNA extraction method in cecal, colon, and fecal samples. However, the two methods significantly differed in samples with comparably low bacterial biomass: cloacal and especially ileal samples. We also sequenced 100 replicate sample pairs to evaluate repeatability during both extraction and PCR stages and found that both methods were highly consistent for cecal, colon, and fecal samples (rs > 0.7) but had low repeatability for cloacal (rs = 0.39) and ileal (rs = -0.24) samples. This study indicates that direct PCR provides a fast, cheap, and reliable alternative to conventional DNA extraction methods for retrieving 16S rRNA data, which can aid future gut microbiome studies. IMPORTANCE The microbial communities of animals can have large impacts on their hosts, and the number of studies using high-throughput sequencing to measure gut microbiomes is rapidly increasing. However, the library preparation procedure in microbiome research is both costly and time-consuming, especially for large numbers of samples. We investigated a cheaper and faster direct PCR method designed to bypass the DNA isolation steps during 16S rRNA library preparation and compared it with a standard DNA extraction method. We used both techniques on five different gut sample types collected from 20 juvenile ostriches and sequenced samples with Illumina MiSeq. The methods were highly comparable and highly repeatable in three sample types with high microbial biomass (cecum, colon, and feces), but larger differences and low repeatability were found in the microbiomes obtained from the ileum and cloaca. These results will help microbiome researchers assess library preparation procedures and plan their studies accordingly.

Genes of the major histocompatibility complex highlight interactions of the innate and adaptive immune system.

BACKGROUND: A well-functioning immune defence is crucial for fitness, but our knowledge about the immune system and its complex interactions is still limited. Major histocompatibility complex (MHC) molecules are involved in T-cell mediated adaptive immune responses, but MHC is also highly upregulated during the initial innate immune response. The aim of our study was therefore to determine to what extent the highly polymorphic MHC is involved in interactions of the innate and adaptive immune defence and if specific functional MHC alleles (FA) or heterozygosity at the MHC are more important. METHODS: To do this we used captive house sparrows (Passer domesticus) to survey MHC diversity and immune function controlling for several environmental factors. MHC class I alleles were identified using parallel amplicon sequencing and to mirror immune function, several immunological tests that correspond to the innate and adaptive immunity were conducted. RESULTS: Our results reveal that MHC was linked to all immune tests, highlighting its importance for the immune defence. While all innate responses were associated with one single FA, adaptive responses (cell-mediated and humoral) were associated with several different alleles. DISCUSSION: We found that repeated injections of an antibody in nestlings and adults were linked to different FA and hence might affect different areas of the immune system. Also, individuals with a higher number of different FA produced a smaller secondary response, indicating a disadvantage of having numerous MHC alleles. These results demonstrate the complexity of the immune system in relation to the MHC and lay the foundation for other studies to further investigate this topic.

Sexually antagonistic evolution caused by male-male competition in the pistil.

Although sexual selection and sexual conflict are important evolutionary forces in animals, their significance in plants is uncertain. In hermaphroditic organisms, such as many plants, sexual conflict may occur both between mating partners (interlocus conflict) and between male and female sex roles within an individual (intralocus conflict). We performed experimental evolution, involving lines that were crossed with either one or two pollen donors (monogamous or polyandrous lines), in the hermaphroditic plant (Collinsia heterophylla) where early fertilizations are associated with female fitness costs (reduced seed set). Artificial polyandry for four generations resulted in enhanced pollen performance and increased female fitness costs compared to the monogamous and source (starting material) lines. Female fitness was also reduced in the monogamous line, indicating a possible trade-off between sex roles, resulting from early pollination. We performed a second experiment to investigate a potential harming effect of pollen performance on seed set. We found that high siring success of early arriving pollen competing with later-arriving pollen was associated with high female fitness costs, consistent with an interlocus sexual conflict. Our study provides evidence for the importance of sexual selection in shaping evolution of plant reproductive strategies, but also pinpoints the complexity of sexual conflict in hermaphroditic species.

Expression and phylogenetic analyses reveal paralogous lineages of putatively classical and non-classical MHC-I genes in three sparrow species (Passer).

BACKGROUND: The Major Histocompatibility Complex (MHC) plays a central role in immunity and has been given considerable attention by evolutionary ecologists due to its associations with fitness-related traits. Songbirds have unusually high numbers of MHC class I (MHC-I) genes, but it is not known whether all are expressed and equally important for immune function. Classical MHC-I genes are highly expressed, polymorphic and present peptides to T-cells whereas non-classical MHC-I genes have lower expression, are more monomorphic and do not present peptides to T-cells. To get a better understanding of the highly duplicated MHC genes in songbirds, we studied gene expression in a phylogenetic framework in three species of sparrows (house sparrow, tree sparrow and Spanish sparrow), using high-throughput sequencing. We hypothesize that sparrows could have classical and non-classical genes, as previously indicated though never tested using gene expression. RESULTS: The phylogenetic analyses reveal two distinct types of MHC-I alleles among the three sparrow species, one with high and one with low level of polymorphism, thus resembling classical and non-classical genes, respectively. All individuals had both types of alleles, but there was copy number variation both within and among the sparrow species. However, the number of highly polymorphic alleles that were expressed did not vary between species, suggesting that the structural genomic variation is counterbalanced by conserved gene expression. Overall, 50% of the MHC-I alleles were expressed in sparrows. Expression of the highly polymorphic alleles was very variable, whereas the alleles with low polymorphism had uniformly low expression. Interestingly, within an individual only one or two alleles from the polymorphic genes were highly expressed, indicating that only a single copy of these is highly expressed. CONCLUSIONS: Taken together, the phylogenetic reconstruction and the analyses of expression suggest that sparrows have both classical and non-classical MHC-I genes, and that the evolutionary origin of these genes predate the split of the three investigated sparrow species 7 million years ago. Because only the classical MHC-I genes are involved in antigen presentation, the function of different MHC-I genes should be considered in future ecological and evolutionary studies of MHC-I in sparrows and other songbirds.

100 million years of multigene family evolution: origin and evolution of the avian MHC class IIB.

BACKGROUND: Gene duplication has led to a most remarkable adaptation involved in vertebrates' host-pathogen arms-race, the major histocompatibility complex (MHC). However, MHC duplication history is as yet poorly understood in non-mammalian vertebrates, including birds. RESULTS: Here, we provide evidence for the evolution of two ancient avian MHC class IIB (MHCIIB) lineages by a duplication event prior to the radiation of all extant birds >100 million years ago, and document the role of concerted evolution in eroding the footprints of the avian MHCIIB duplication history. CONCLUSIONS: Our results suggest that eroded footprints of gene duplication histories may mimic birth-death evolution and that in the avian MHC the presence of the two lineages may have been masked by elevated rates of concerted evolution in several taxa. Through the presence of a range of intermediate evolutionary stages along the homogenizing process of concerted evolution, the avian MHCIIB provides a remarkable illustration of the erosion of multigene family duplication history.