Closely related host species share similar symbionts, but the effects of host genetic admixture and environmental conditions on these communities remain largely unknown. We investigated the influence of host genetic admixture and environmental factors on the intestinal prokaryotic and eukaryotic communities (fungi, parasites) of two house mouse subspecies (Mus musculus domesticus and M. m. musculus) and their hybrids in two settings: (i) wild-caught mice from the European hybrid zone and (ii) wild-derived inbred mice in a controlled laboratory environment before and during a community perturbation (infection). In wild-caught mice, environmental factors strongly predicted the overall microbiome composition. Subspecies' genetic distance significantly influenced the overall microbiome composition, and each component (bacteria, parasites and fungi). While hybridization had a weak effect, it significantly impacted fungal composition. We observed similar patterns in wild-derived mice, where genetic distances and hybridization influenced microbiome composition, with fungi being more stable to infection-induced perturbations than other microbiome components. Subspecies' genetic distance has a stronger and consistent effect across microbiome components than differences in expected heterozygosity among hybrids, suggesting that host divergence and host filtering play a key role in microbiome divergence, influenced by environmental factors. Our findings offer new insights into the eco-evolutionary processes shaping host-microbiome interactions.

• Klíčová slova
• host–microbiome interactions, hybridization, microbiome, spatial environment, species barriers,
• MeSH
• biologická evoluce MeSH
• hybridizace genetická * MeSH
• interakce mikroorganismu a hostitele MeSH
• mikrobiota MeSH
• myši MeSH
• střevní mikroflóra MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Mastophorus muris (Gmelin, 1790) is a globally distributed parasitic nematode of broad range mammals. The taxonomy within the genus Mastophorus and the cryptic diversity among the genus are controversial among taxonomists. This study provides a detailed morphological description of M. muris from Mus musculus combined with a molecular phylogenetic approach. Moreover, descriptions and molecular data of M. muris from non-Mus rodents and wildcats complement our findings and together provide new insights into their taxonomy. The analysis of M. muris was based on light microscopy and scanning electron microscopy. The morphological description focused on the dentition pattern of the two trilobed pseudolabia. Additionally, we described the position of the vulva, arrangement of caudal pairs of papillae, spicules and measured specimens from both sexes and the eggs. For the molecular phylogenetic approach, we amplified the small subunit ribosomal RNA gene and the internal transcribed spacer, and the cytochrome c oxidase subunit 1. Mastophorus morphotypes based on dentition patterns and phylogenetic clustering indicate a subdivision of the genus in agreement with their host. We recognize two groups without a change to formal taxonomy: One group including those specimens infecting Mus musculus, and the second group including organisms infecting non-Mus rodents. Our genetic and morphological data shed light into the cryptic diversity within the genus Mastopohorus. We identified two host-associated groups of M. muris. The described morphotypes and genotypes of M. muris allow a consistent distinction between host-associated parasites.

• Klíčová slova
• Mastophorus muris, Mus musculus, Nematoda, Phylogeny, Scanning electron microscopy,
• MeSH
• DNA helmintů genetika   MeSH
• fylogeneze * MeSH
• genetická variace MeSH
• mezerníky ribozomální DNA genetika   MeSH
• mikroskopie elektronová rastrovací * MeSH
• mikroskopie MeSH
• molekulární sekvence - údaje MeSH
• myši MeSH
• respirační komplex IV genetika   MeSH
• ribozomální DNA genetika   MeSH
• sekvenční analýza DNA MeSH
• shluková analýza MeSH
• Spiruroidea klasifikace   genetika   anatomie a histologie   izolace a purifikace   ultrastruktura   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DNA helmintů MeSH
• mezerníky ribozomální DNA MeSH
• respirační komplex IV MeSH
• ribozomální DNA MeSH

Resistance (host capacity to reduce parasite burden) and tolerance (host capacity to reduce impact on its health for a given parasite burden) manifest two different lines of defense. Tolerance can be independent from resistance, traded off against it, or the two can be positively correlated because of redundancy in underlying (immune) processes. We here tested whether this coupling between tolerance and resistance could differ upon infection with closely related parasite species. We tested this in experimental infections with two parasite species of the genus Eimeria. We measured proxies for resistance (the (inverse of) number of parasite transmission stages (oocysts) per gram of feces at the day of maximal shedding) and tolerance (the slope of maximum relative weight loss compared to day of infection on number of oocysts per gram of feces at the day of maximal shedding for each host strain) in four inbred mouse strains and four groups of F1 hybrids belonging to two mouse subspecies, Mus musculus domesticus and Mus musculus musculus. We found a negative correlation between resistance and tolerance against Eimeria falciformis, while the two are uncoupled against Eimeria ferrisi. We conclude that resistance and tolerance against the first parasite species might be traded off, but evolve more independently in different mouse genotypes against the latter. We argue that evolution of the host immune defenses can be studied largely irrespective of parasite isolates if resistance-tolerance coupling is absent or weak (E. ferrisi) but host-parasite coevolution is more likely observable and best studied in a system with negatively correlated tolerance and resistance (E. falciformis).

• Klíčová slova
• Eimeria, coevolution, resistance, tolerance,
• Publikační typ
• časopisecké články MeSH

Intracellular parasites of the genus Eimeria are described as tissue/host-specific. Phylogenetic classification of rodent Eimeria suggested that some species have a broader host range than previously assumed. We explore whether Eimeria spp. infecting house mice are misclassified by the most widely used molecular markers due to a lack of resolution, or whether, instead, these parasite species are indeed infecting multiple host species.With the commonly used markers (18S/COI), we recovered monophyletic clades of E. falciformis and E. vermiformis from Mus that included E. apionodes identified in other rodent host species (Apodemus spp., Myodes glareolus, and Microtus arvalis). A lack of internal resolution in these clades could suggest the existence of a species complex with a wide host range infecting murid and cricetid rodents. We question, however, the power of COI and 18S markers to provide adequate resolution for assessing host specificity. In addition to the rarely used marker ORF470 from the apicoplast genome, we present multilocus genotyping as an alternative approach. Phylogenetic analysis of 35 nuclear markers differentiated E. falciformis from house mice from isolates from Apodemus hosts. Isolates of E. vermiformis from Mus are still found in clusters interspersed with non-Mus isolates, even with this high-resolution data.In conclusion, we show that species-level resolution should not be assumed for COI and 18S markers in coccidia. Host-parasite cospeciation at shallow phylogenetic nodes, as well as contemporary coccidian host ranges more generally, is still open questions that need to be addressed using novel genetic markers with higher resolution.

• Klíčová slova
• 18S, COI, Eimeria, multilocus sequence typing, phylogenetics, rodents,
• Publikační typ
• časopisecké články MeSH