Biology subjects

Macholan, M.

Publications and source records attributed to Macholan, M..

5 recordsLinked to original sources

bioRxiv2023

Phenogenomic resources immortalized in a panel of wild-derived strains of five species of house mice

The house mouse, Mus musculus, is a widely used animal model in biomedical research, with classical laboratory strains (CLS) being the most frequently employed. However, the limited genetic variability in CLS hinders their applicability in evolutionary studies. Wild-derived strains (WDS), on the other hand, provide a suitable resource for such investigations. This study quantifies genetic and phenotypic data of 101 WDS representing 5 species, 3 subspecies, and 8 natural Y consomic strains and compares them with CLS. Genetic variability was estimated using whole mtDNA sequences, the Prdm9 gene, and copy number variation at two sex chromosome-linked genes. WDS exhibit a large natural variation with up to 2173 polymorphic sites in mitogenomes, whereas CLS display 92 sites. Moreover, while CLS have two Prdm9 alleles, WDS harbour 46 different alleles. Although CLS resemble M. m. domesticus and M. m. musculus WDS, they differ from them in 8 and 11 out of 15 phenotypic traits, respectively. The results suggest that WDS can be a useful tool in evolutionary studies and have great potential for medical applications.

evolutionary biology↗

bioRxiv2023

The effect of host admixture on wild house mouse gut microbiota is weak when accounting for spatial autocorrelation.

The question of how interactions between the gut microbiome and vertebrate hosts contribute to host adaptation and speciation is one of the major problems in current evolutionary research. Using bacteriome and mycobiome metabarcoding, we examined how these two components of the gut microbiota vary with the degree of host admixture in secondary contact between two house mouse subspecies (Mus musculus musculus and M. m. domesticus). We used a large dataset collected at two replicates of the hybrid zone and model-based statistical analyses to ensure the robustness of our results. Assuming that the microbiota of wild hosts suffers from spatial autocorrelation, we directly compared the results of statistical models that were spatially naive with those that accounted for spatial autocorrelation. We showed that neglecting spatial autocorrelation can drastically affect the results and lead to misleading conclusions. The spatial analyses showed little difference between subspecies, both in microbiome composition and in individual bacterial lineages. Similarly, the degree of admixture had minimal effects on the gut bacteriome and mycobiome and was caused by changes in a few microbial lineages that correspond to the common symbionts of free-living house mice. In contrast to previous studies, these data do not support the hypothesis that the microbiota plays an important role in host reproductive isolation in this particular model system.

evolutionary biology↗

bioRxiv2021

Copy number variation of the putative speciation genes in the European house mouse hybrid zone

AO_SCPLOWBSTRACTC_SCPLOWHybrid zones have long been described as "windows on the evolutionary process", and studying them has become even more important since the advance in the genome analysis tools. The hybrid zone between two subspecies of the house mouse (Mus musculus musculus and Mus m. domesticus) is a unique model speciation system to study fine scale interactions of recently diverged genomes. Here, we explore the role of gene Copy Number Variation in shaping the barrier to introgression in the hybrid zone within a previously established transect in Central Europe. The CNV of seven pre-selected candidate genes was determined via droplet-digital PCR and analyzed in the context of ~500k SNPs, with the ancestral population (i.e. musculus or domesticus) of every SNP allele previously inferred in the admixed individuals (Baird et al., in prep.). The copy numbers of five genes were clearly associated with the prevalence of either musculus or domesticus genomes across the hybrid zone. In three cases, the highest and/or outlying levels of association were observed at or very close to the annotated positions of the respective gene amplicons, demonstrating the power of our approach in confirming the reference locations of copy number variants. Notably, several other reference locations were recognized as positive outliers in the association with particular CNV genes, possibly representing the extra gene copies and/or their epistatic interaction sites.

evolutionary biology↗

bioRxiv2019

Widespread introgression of the Mus musculus musculus Y chromosome in Central Europe

According to Haldanes rule, sex chromosomes should harbour more incompatibilities than autosomes. As a consequence, transmission of sex-linked genes across a genetic barrier is expected to be hampered. A remarkable example of a contradiction of this assumption was reported from the hybrid zone between two house mouse subspecies in western Czechia and south-eastern Germany where unidirectional east[->]west Y chromosome introgression was observed. Since the phenomenon was coupled with differences in sex ratio, this was hypothesised to be caused by a genetic conflict between sex-specific genes on sex chromosomes or elsewhere in the genome. Here we capitalise on a large material consisting of almost 7500 mice collected across a vast area from the Baltic Sea to the Alps embracing a ~900 km long portion of the zone with the aim to (i) detect its exact course and (ii) reveal the extent and pattern of the Y chromosome introgression in Central Europe. We show that the path of the zone is quite tortuous even at the global scale and the introgression is rather a rule than an exception. We also show that although sex ratio perturbations described in our previous study appear also in other introgression areas, they may not be ubiquitous. Finally, we reveal that although not all Y chromosome types are associated with the introgression, it is not restricted to a single winning haplotype.

evolutionary biology↗

bioRxiv2019

Intensity of infection with intracellular Eimeria spp. and pinworms is reduced in hybrid mice compared to parental subspecies

The longstanding impression that hybrid mice are more highly parasitized and therefore less fit than parentals persists despite the findings of recent studies. Working across a novel transect of the European House Mouse hybrid zone we assessed intracellular infections by Eimeria, a parasite of high pathogenicity, and infections by pinworms, assumed to be less pathogenic. For Eimeria we found lower intensities in hybrid hosts than in parental mice but no evidence of lowered probability of infection in the centre of the hybrid zone. This means ecological and epidemiological factors are very unlikely to be responsible for the reduced load of infected hybrids. Focussing on parasite intensity (load in infected hosts) we also corroborated reduced pinworm loads reported for hybrid mice in previous studies. In addition we questioned whether differences in body condition during infection would indicate different impacts on hybrid vs. parental hosts health. We couldnt show such an effect. We conclude that intensity of diverse parasites, including the previously unstudied Eimeria, is reduced in hybrid mice compared to parental subspecies. We suggest caution in extrapolating this to differences in hybrid host fitness in the absence of, for example, evidence for a link between parasitemia and health.

evolutionary biology↗