Michal Vinkler

• doc. RNDr., Ph.D.
• Researcher at Charles University in Prague

Animal hosts can adapt to emerging infectious disease through both disease resistance, which decreases pathogen numbers, and disease tolerance, which limits damage during infection without limiting pathogen replication. Both resistance and tolerance mechanisms can drive pathogen transmission dynamics. However, it is not well understood how quickly...

Driven by co-evolution with pathogens, host immunity continuously adapts to optimize defence against pathogens within a given environment. Recent advances in genetics, genomics and transcriptomics have enabled a more detailed investigation into how immunogenetic variation shapes the diversity of immune responses seen across domestic and wild animal...

Digestive and respiratory tracts are inhabited by rich bacterial communities that can vary between their different segments. In comparison with other bird taxa with developed caeca, parrots that lack caeca have relatively lower variability in intestinal morphology. Here, based on 16S rRNA metabarcoding, we describe variation in microbiota across di...

Toll-like receptors (TLRs) form a key component of animal innate immunity, being responsible for recognition of conserved microbial structures. As such, TLRs may be subject to diversifying and balancing selection, which maintains allelic variation both within and between populations. However, most research on TLRs is presently in non-model avian sp...

During early ontogeny, microbiome affects development of the gastrointestinal tract, immunity and survival in vertebrates. Bird egg has been suggested to be either (1) initially sterile (Sterile egg hypothesis) and (2) colonized through horizontal trans-shell migration after egg laying, or (3) initially seeded with bacteria through vertical transfe...

Retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated protein 5 (MDA5) are key RNA virus sensors belonging to the RIG-I-like receptor (RLR) family. The activation of the RLR inflammasome leads to the establishment of antiviral state, mainly through interferon-mediated signaling. The evolutionary dynamics of RLRs has been st...

In vertebrates, cannabinoids modulate neuroimmune interactions through two cannabinoid receptors (CNRs) conservatively expressed in the brain (CNR1, syn. CB1) and in the periphery (CNR2, syn. CB2). Our comparative genomic analysis indicates several evolutionary losses in the CNR2 gene that is involved in immune regulation. Notably, we show that the...

The interactions of evolutionary forces are difficult to analyse in free‐living populations. However, when properly understood, they provide valuable insights into evolutionary biology and conservation genetics. This is particularly important for the interplay of genetic drift and natural selection in immune genes that confer resistance to disease....

Balancing selection is a classic mechanism for maintaining variability in immune genes involved in host-pathogen interactions. However, it remains unclear how widespread the mechanism is across immune genes other than the Major Histocompatibility Complex (MHC). While occasional reports suggest that balancing selection (heterozygote advantage, negat...

Adult neurogenesis is the life-long process of neural stem cell proliferation, differentiation into neurons, migration, and incorporation into the existing neuronal circuits. After decades of research, it is now widely accepted that mammals and birds retain the capacity to regenerate neurons even after their subadult ontogeny. Cerebrospinal fluid p...

In vertebrates, an ancient duplication in the genes for cannabinoid receptors (CNRs) allowed the evolution of specialised endocannabinoid receptors expressed in the brain (CNR1) and the periphery (CNR2). While dominantly conserved throughout vertebrate phylogeny, our comparative genomic analysis suggests that certain taxa may have lost either the C...

While seasonal trends in testosterone levels are known from cross-cohort studies, data on testosterone inter-annual individual repeatability in wild birds are rare. Also, our understanding of hormonal age-dependent changes in testosterone levels is limited. We assessed plasma testosterone levels in 105 samples originating from 49 repeatedly capture...

Immune defenses vary widely across individuals and species. The field of evolutionary and ecological immunology (also recognized as ecoimmunology) seeks to uncover both the ultimate and proximate drivers of this variability. In this chapter, we review key research areas, techniques, and future directions in this field, with a specific focus on free...

Penguins (Sphenisciformes) are an iconic order of flightless, diving seabirds distributed across a large latitudinal range in the Southern Hemisphere. The extensive area over which penguins are endemic is likely to have fostered variation in pathogen pressure, which in turn will have imposed differential selective pressures on the penguin immune sy...

Two key cytosolic receptors belonging to the retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) family sense the viral RNA-derived danger signals: RIG-I and melanoma differentiation-associated protein 5 (MDA5). Their activation establishes an antiviral state by downstream signaling that ultimately activates interferon-stimulated genes (ISGs...

The first-line effector mechanisms of immune defence, including inflammation and oxidative burst, contribute significantly to host-pathogen resistance. Whether these immune responses undergo age-related changes in birds remains unknown. Here, we tracked selected inflammatory parameters in 54 free-living great tits (Parus major) of known age, captur...

Cerebrospinal fluid (CSF) proteins regulate neurogenesis, brain homeostasis and participate in signalling during neuroinflammation. Even though birds represent valuable models for constitutive adult neurogenesis, current proteomic studies of the avian CSF are limited to chicken embryos. Here we use liquid chromatography–tandem mass spectrometry (nL...

Proteins encoded by Antigen Processing Genes (APGs) prepare antigens for presentation by the Major Histocompatibility Complex class I (MHC I) molecules. Coevolution between APGs and MHC I genes has been proposed as the ancestral gnathostome condition. The hypothesis predicts a single highly expressed MHC I gene and tight linkage between APGs and MH...

Cerebrospinal fluid (CSF) proteins regulate neurogenesis, brain homeostasis and participate in signalling during neuroinflammation. Even though birds represent valuable models for constitutive adult neurogenesis, current proteomic studies of the avian CSF are limited to chicken embryos. Here we use liquid chromatography–tandem mass spectrometry (nL...

10.1101/2020.07.23.217836

While seasonal trends in the testosterone-driven hormonal regulation of resource allocation are known from cohort population samples, data on the inter-annual individual stability of blood plasma testosterone levels in wild birds are lacking, and our understanding of age-dependent changes is limited. We assessed plasma testosterone levels in 105 sa...

Despite widespread variability and redundancy abounding animal immunity, little is currently known about the rate of evolutionary convergence (functionally analogous traits not inherited from a common ancestor) in host molecular adaptations to parasite selective pressures. Toll‐like receptors (TLRs) provide the molecular interface allowing hosts to...

Background The interferon-induced transmembrane (IFITM) protein family comprises a class of restriction factors widely characterised in humans for their potent antiviral activity. Their biological activity is well documented in several animal species, but their genetic variation and biological mechanism is less well understood, particularly in avia...

Abstract Immune genes show remarkable levels of adaptive variation shaped by pathogen-mediated selection. Compared to humans, however, population polymorphism in animals has been understudied. To provide an insight into immunogenetic diversity in birds, we sequenced complete protein-coding regions of all Toll-like receptor (TLR) genes with direct o...

Avian egg white is essential for protecting and nourishing bird embryos during their development. Being produced in the female magnum, variability in hen oviduct gene expression may affect egg white composition in domestic chickens. Since traditional poultry breeds may represent a source of variation, in the present study we describe the egg white...

Toll-like receptors (TLRs) are key sensor molecules in vertebrates triggering initial phases of immune responses to pathogens. The avian TLR family typically consists of ten receptors, each adapted to distinct ligands. To understand the complex evolutionary history of each avian TLR, we analysed all members of the TLR family in the whole genome ass...

Positive selection acting on Toll‐like receptors (TLRs) has been recently investigated to reveal evolutionary mechanisms of host‐pathogen molecular co‐adaptation. Much of this research, however, has focused mainly on the identification of sites predicted to be under positive selection, bringing little insight into the functional differences and sim...

The phenotype-linked fertility hypothesis (PLFH) proposes that both sexual ornaments and sperm traits are phenotypically plastic and co-affected by environmental factors through individual condition, resulting in a positive correlation between ornament expression and functional fertility. Ornaments may then serve females in the identification of th...

The recent emergence of the poultry bacterial pathogen Mycoplasma gallisepticum (MG) in free-living house finches (Haemorhous mexicanus), which causes mycoplasmal conjunctivitis in this passerine bird species, resulted in a rapid coevolutionary arms-race between MG and its novel avian host. Despite extensive research on the ecological and evolution...

Urban environmental pollution results in contamination of the tissues of synanthropic organisms by toxic trace elements with potential impacts on human health. Passerine birds may serve as convenient indicators of such contamination. In this study we investigated the effect of blood and plumage contamination with heavy metals (lead Pb, cadmium Cd,...

The gastrointestinal tract of vertebrates is inhabited by diverse bacterial communities that induce marked effects on the host physiology and health status. The composition of the gastrointestinal microbiota is characterized by pronounced taxonomic and functional variability among different regions of the vertebrate gastrointestinal tract. Despite...

Taxonomic composition of the great tit GIT microbiota and its variation between oral and faecal samples. (XLSX)

Detail listing of great tit samples including the GIT region (faecal or oral), individual identity (ID), accession number, sex and body weight. (XLSX)

While haematological variation is well known in birds, variation in avian breeds (distinct morphotypes of the same species) remains unexplored. Poultry breeds, in particular, may show interesting evolutionary patterns and economically-relevant physiological differences. We performed a comparative examination of blood cellular composition in five ch...

The skin-swelling test is a simple and widespread method used in field ecological research to estimate cellular immune responsiveness in animals. This immunoecological test is based on measuring the magnitude of tissue swelling response at specific times following subcutaneous application of an experimental pro-inflammatory stimulant. In the vast m...

According to the viability indicator hypothesis, ornaments of many bird species honestly signal individual quality and health status. In this study, we investigated the health- and stress-indicating capacity of both feather- and skin-based ornamental traits in the grey partridge (Perdix perdix), a vulnerable avian species of the European agricultur...

Several recent hypotheses consider oxidative stress to be a primary constraint ensuring honesty of condition-dependent carotenoid-based signalling. The key testable difference between these hypotheses is the assumed importance of carotenoids for redox homeostasis, with carotenoids being either antioxidant, pro-oxidant or unimportant. We tested the...

J subgroup avian leukosis virus (ALV-J) infects domestic chicken, jungle fowl, and turkey and enters the host cell through a receptor encoded by tvj locus and identified as Na+/H+ exchanger 1 (NHE1). The resistance to ALV-J in a great majority of examined galliform species was explained by deletions or substitutions of the critical tryptophan 38 in...

The nucleotide alignment of the partial NHE1 sequence of eight geese species. Nucleotides matching the database sequence of domestic goose are on a gray background. The non-conserved nucleotides changing the amino-acid translation are in red. The first predicted amino-acid of the ECL1 is in green. (DOCX)

The nucleotide alignment of the partial NHE1 sequence of 15 duck species. Nucleotides matching the database sequence of domestic duck are on a gray background. The non-conserved nucleotides changing the amino-acid translation are in red. The first predicted amino-acid of the ECL1 is in green. The color bacground denotes nucleotides heterozygous in...

Partial cDNA sequence of NHE1 of gray partridge and corresponding amino-acid sequence. (DOCX)

The phytohaemagglutinin (PHA) skin-swelling test, a common ecological method for measuring immune responsiveness, uses a subcutaneous injection of PHA to induce an inflammatory response with metrically measurable swelling. Both the immunological basis of this response and the role of pre-exposure physiology remain poorly understood, however, preven...

Immunity exhibits extraordinarily high levels of variation. Evolution of the immune system in response to host-pathogen interactions in particular ecological contexts appears to be frequently associated with diversifying selection increasing the genetic variability. Many studies have documented that immunologically relevant polymorphism observed to...

Supplement 1 lists published research articles dealing with TSP in vertebrate immune genes available on Web of Science [final update 19th March 2015]. Articles dealing with TSP in blood group systems and serological allomorphs were not included into this survey.

Toll-like receptors (TLRs) are a cornerstone of vertebrate innate immunity. In this study, we identified orthologues of TLR4, TLR5 and TLR7 (representing both bacterial- and viral-sensing TLRs) in the grey partridge (Perdix perdix), a European Galliform game bird species. The phylogeny of all three TLR genes follows the known phylogeny of Galloanse...

Toll-like receptors (TLR) are essential activators of the innate part of the vertebrate immune system. In this study, we analysed the interspecific variability of three TLR (bacterial-sensing TLR4 and TLR5 and viral-sensing TLR7) within the Galloanserae bird clade, investigated their phylogeny, assessed their structural conservation and estimated s...

Detailed investigation of variation in genes involved in pathogen recognition is crucial for understanding co-evolutionary processes between parasites and their hosts. Triggering immediate innate response to invading microbes, Toll-like receptors (TLRs) belong presently among the best-studied receptors of vertebrate immunity. TLRs exhibit remarkabl...

Extra-pair copulation without apparent direct benefits is an evolutionary puzzle that requires indirect fitness benefits to females to explain its ubiquity in socially monogamous mating systems. Using wild scarlet rosefinches (Carpodacus erythrinus), we tested if genetic benefits in the form of global (microsatellite) heterozygote advantage, adapti...

Researchers interested in ecological immunology face substantial methodological problems: 1) most immunological approaches are difficult to perform in free-living animals, 2) in some of the applicable methods the immunological background of the test remains unclear. The latter is also true for the phytohaemagglutinin (PHA) skin-swelling test, a tra...

In vertebrates, it has been repeatedly demonstrated that genes encoding proteins involved in pathogen-recognition by adaptive immunity (e.g. MHC) are subject to intensive diversifying selection. On the other hand, the role and the type of selection processes shaping the evolution of innate-immunity genes are currently far less clear. In this study...

Birds express various secondary ornaments that can indicate individual condition and health. Amongst these, red-coloured carotenoid-based ornaments are supposed to be particularly valuable predictors of individual quality, due to their sensitivity to oxidative stress. Nevertheless, melanin-pigmented traits might also signal health and immune functi...

As proposed by the ‘good parent model’ for evolution of secondary male ornamentation, secondary ornaments may signal male provisioning rates and, therefore, direct benefit to females. On the other hand, male parental care intensity can potentially be affected by the occurrence of extra-pair offspring in its nest. According to ‘parental investment t...

We studied haemosporidian parasites in the scarlet rosefinch Carpodacus erythrinus in a small isolated semicolony during an eight-year period using molecular methods of parasite detection. The scarlet rosefinch is an interesting model of parasite host species. It winters in South Asia which represents a rare exception among European passerines. Mal...

The attractiveness hypothesis predicts that females should bias the sex ratio of their offspring towards sons when mated to attractive males. Females of many socially monogamous bird species commonly engage in extra-pair fertilizations (EPFs). Assuming that extra-pair males are more attractive to females than their social partners, and that sons in...

The phytohaemagglutinin (PHA) skin-swelling test is one of the most widely used methods for cell-mediated immunity measurement in immunoecology. Although several studies have investigated the condition-dependent traits associated with the magnitude of cutaneous inflammatory response to PHA, the results concerning signalling of the responsiveness th...

‘Immunocompetence’ is a term used in avian immunological ecology to refer to the ability of an individual to overcome potential parasite infections. However, there are multiple ecological definitions of this term currently used and all of them are rather liberal in immunological terms. This prevents much of the potential intellectual interchange be...

Adaptive immunity is commonly viewed as a unique vertebrate feature. A misleading view on vertebrate longevity compared to non-vertebrate animals together with oversimplification of ‘invertebrate’ phylogeny sometimes serves for justifying the limitation of adaptive immunity exclusively to vertebrates. However, here we emphasise that the borderline...

Genes of the Major Histocompatibility Complex (MHC) represent an essential component of the vertebrate acquired immune system. In the last decades, the role of MHC genes in mate choice has been subject of particular scientific interest. However, results of studies dealing with this topic in different species are equivocal and mechanisms conducting...

Carotenoids belong to biochemicals essential in the animal diet. This is due to their indispensability in several life-preserving physiological processes. In many species, however, carotenoids serve also as the main pigments colouring various ornamental structures engaged in the mate choice. Although intensively studied by biologists, the evolution...

Haematological methods are widely utilised among avian ecologists as a means for individual health assessment. However, the technical simplicity of some of the tests may easily lead to oversimplification of the evaluation. Here, we show in the Scarlet Rosefinch (Carpodacus erythrinus) that haematological parameters other than the widely used hetero...

1. The phytohaemagglutinin (PHA) skin-swelling test is widely used in immunoecology and ecotoxicology to estimate cell-mediated immunity. Although often presumed, the involvement of T cells in generating an immune response to PHA in vivo remains unclear. 2. To investigate the mechanism triggering this response we have compared in zebra finch (Taeni...

Despite considerable research effort, it remains unclear whether extra-pair fertilizations (EPF) drive the evolution of male secondary ornamentation in socially monogamous systems. In this study, we test the hypothesis that EPF contribute to the evolution or maintenance of male feather ornamentation in a sexually dichromatic passerine, the Scarlet...

Despite a reasonable scientific interest in sexual selection, the general principles of health signalisation via ornamental traits remain still unresolved in many aspects. This is also true for the mechanism preserving honesty of carotenoid-based signals. Although it is widely accepted that this type of ornamentation reflects an allocation trade-of...

Toll-like receptors (TLRs) are the basic components of the vertebrate pathogen recognition system. Despite uniform general structure, remarkable variability in domain composition can be found in individual TLRs among species. Knowledge of interspecific differences is of particular importance to our understanding of selective pressures on TLRs. Curr...

In the last decade a great effort has been devoted in animal evolutionary ecology to searching for interindividual and interspecific differences in anti-parasite resistance. Although many examples of variability in health-related traits were described in natural animal populations, our knowledge about the underlying genetic features determining thi...