In social species such as house mouse, being dominant is vital. Determination of dominance may st... more In social species such as house mouse, being dominant is vital. Determination of dominance may start early in life and vary during ontogeny. We asked whether pre-pubertal and adolescent behaviour predicts the rank a male mouse finally obtains. Moreover, we asked how dominant vs. subordinate adults differ in exploration and propensity to emigrate. We studied fraternal pairs as the simple social units, from weaning to full-grown adulthood. By utilizing two mouse subspecies known to differ in many behavioural traits, we take into account any potential subspecific idiosyncrasies. We did not find any significant effect of future social status on any behavioural type displayed before adulthood, but the subspecies themselves differ in behaviours prevailing in particular ontogeny phases. While musculus males start as more pro-social, they later became significantly more passive. Conversely, domesticus are slightly less passive at the beginning but significantly more proactive close to adulthood and rapidly establishing hierarchy through overt conflicts. We found no difference in exploration between ranks, however, domesticus males were significantly more active in an unknown area than musculus. Most importantly, while dominant domesticus males seem to be more prone to emigration, in musculus it was the subordinate males who left base significantly more often. This is consistent with extended contests of musculus males over dominance found in this study as well as with differences in endocrinological changes we have reported previously.
The gastrointestinal microbiota (GM) is considered an important component of the vertebrate holob... more The gastrointestinal microbiota (GM) is considered an important component of the vertebrate holobiont. GM–host interactions influence the fitness of holobionts and are, therefore, an integral part of evolution. The house mouse is a prominent model for GM–host interactions, and evidence suggests a role for GM in mouse speciation. However, previous studies based on short 16S rRNA GM profiles of wild house mouse subspecies failed to detect GM divergence, which is a prerequisite for the inclusion of GM in Dobzhansky–Muller incompatibilities. Here, we used standard 16S rRNA GM profiling in two mouse subspecies, Mus musculus musculus and M. m. domesticus, including the intestinal mucosa and content of three gut sections (ileum, caecum, and colon). We reduced environmental variability by sampling GM in the offspring of wild mice bred under seminatural conditions. Although the breeding conditions allowed a contact between the subspecies, we found a clear differentiation of GM between them, ...
It is widely acknowledged that population structure can have a substantial impact on evolutionary... more It is widely acknowledged that population structure can have a substantial impact on evolutionary trajectories. In social animals, this structure is strongly influenced by relationships among the population members, so studies of differences in social structure between diverging populations or nascent species are of prime interest. Ideal models for such a study are two house mouse subspecies, Mus musculus musculus and M. m. domesticus, meeting in Europe along a secondary contact zone. Though the latter subspecies has usually been supposed to form tighter and more isolated social units than the former, the evidence is still inconclusive. Here, we carried out a series of radio-frequency identification experiments in semi-natural enclosures to gather large longitudinal datasets on individual mouse movements. The data were summarised in the form of uni- and multi-layer social networks. Within them, we could delimit and describe the social units (‘modules’). While the number of estimated...
Behavioural isolation may lead to complete speciation when partial postzygotic isolation acts in ... more Behavioural isolation may lead to complete speciation when partial postzygotic isolation acts in the presence of divergent specific mate recognition systems. These conditions exist where Mus musculus musculus and M. m. domesticus come into contact and hybridize. We studied two mate recognition signal systems, based on urinary and salivary proteins, across a Central European portion of the mouse hybrid zone. Introgression of the genomic regions responsible for these signals: the major urinary proteins (MUPs) and androgen binding proteins (ABPs) respectively, was compared to introgression at loci assumed to be nearly neutral and those under selection against hybridization. The preference of individuals taken from across the zone regarding these signals was measured in Y mazes, and we develop a model for the analysis of the transition of such traits under reinforcement selection. The strongest assortative preferences were found in males for urine and females for ABP. Clinal analyses confirm nearly neutral introgression of an Abp locus and two loci closely linked to the Abp gene cluster whereas two markers flanking the Mup gene region reveal unexpected introgression. Geographic change in the preference traits matches our reinforcement selection model significantly better than standard cline models. Our study confirms that behavioural barriers are important components of reproductive isolation between the house mouse subspecies
Hybrid zones have long been described as “windows on the evolutionary process”, and studying them... more Hybrid 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 musculusandMus 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.musculusordomesticus) 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 eithermusculusordomesticusgenomes across the hybrid zone. In three cases, the highest and...
The longstanding impression that hybrid mice are more highly parasitized and therefore less fit t... more 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 byEimeria, a parasite of high pathogenicity, and infections by pinworms, assumed to be less pathogenic. ForEimeriawe 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 couldn’t show such an effect. We c...
A synopsis of cytogenetic studies performed on various species and populations of myoxids is pres... more A synopsis of cytogenetic studies performed on various species and populations of myoxids is presented. Interspecific phylogenetic relationships derived from chromosomal data are evaluated and the evolutionary importance of intraspecific karyotypic variation is discussed. New data on the karyotypes of Dtyomys nifedula from Asia and Muscardinus avellanarius from Europe are presented and discussed with special emphasis on the contrasting pattern of chromosomal differentiation in Eliornys vs. Dryomys and other myoxids. A bibliography of myoxid cytogenetics and karyology is compiled. RIASSUNTO-Variazione cromosomica e sistematica dei Mioxidi-Viene presentata una sinossi degli studi citogenetici effettuati su varie specie e popolazioni di Mioxidi. Vengono valutate le relazioni filogenetiche interspecifiche derivate da dati cromosomici e viene discussa l'importanza evolutiva della variazione cariotipica intraspecifica. Vengono presentati nuovi dati sui cariotipi di Dryomys nitedula as...
According to Haldane’s rule, sex chromosomes should harbour more incompatibilities than autosomes... more According to Haldane’s 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...
In social species such as house mouse, being dominant is vital. Determination of dominance may st... more In social species such as house mouse, being dominant is vital. Determination of dominance may start early in life and vary during ontogeny. We asked whether pre-pubertal and adolescent behaviour predicts the rank a male mouse finally obtains. Moreover, we asked how dominant vs. subordinate adults differ in exploration and propensity to emigrate. We studied fraternal pairs as the simple social units, from weaning to full-grown adulthood. By utilizing two mouse subspecies known to differ in many behavioural traits, we take into account any potential subspecific idiosyncrasies. We did not find any significant effect of future social status on any behavioural type displayed before adulthood, but the subspecies themselves differ in behaviours prevailing in particular ontogeny phases. While musculus males start as more pro-social, they later became significantly more passive. Conversely, domesticus are slightly less passive at the beginning but significantly more proactive close to adulthood and rapidly establishing hierarchy through overt conflicts. We found no difference in exploration between ranks, however, domesticus males were significantly more active in an unknown area than musculus. Most importantly, while dominant domesticus males seem to be more prone to emigration, in musculus it was the subordinate males who left base significantly more often. This is consistent with extended contests of musculus males over dominance found in this study as well as with differences in endocrinological changes we have reported previously.
The gastrointestinal microbiota (GM) is considered an important component of the vertebrate holob... more The gastrointestinal microbiota (GM) is considered an important component of the vertebrate holobiont. GM–host interactions influence the fitness of holobionts and are, therefore, an integral part of evolution. The house mouse is a prominent model for GM–host interactions, and evidence suggests a role for GM in mouse speciation. However, previous studies based on short 16S rRNA GM profiles of wild house mouse subspecies failed to detect GM divergence, which is a prerequisite for the inclusion of GM in Dobzhansky–Muller incompatibilities. Here, we used standard 16S rRNA GM profiling in two mouse subspecies, Mus musculus musculus and M. m. domesticus, including the intestinal mucosa and content of three gut sections (ileum, caecum, and colon). We reduced environmental variability by sampling GM in the offspring of wild mice bred under seminatural conditions. Although the breeding conditions allowed a contact between the subspecies, we found a clear differentiation of GM between them, ...
It is widely acknowledged that population structure can have a substantial impact on evolutionary... more It is widely acknowledged that population structure can have a substantial impact on evolutionary trajectories. In social animals, this structure is strongly influenced by relationships among the population members, so studies of differences in social structure between diverging populations or nascent species are of prime interest. Ideal models for such a study are two house mouse subspecies, Mus musculus musculus and M. m. domesticus, meeting in Europe along a secondary contact zone. Though the latter subspecies has usually been supposed to form tighter and more isolated social units than the former, the evidence is still inconclusive. Here, we carried out a series of radio-frequency identification experiments in semi-natural enclosures to gather large longitudinal datasets on individual mouse movements. The data were summarised in the form of uni- and multi-layer social networks. Within them, we could delimit and describe the social units (‘modules’). While the number of estimated...
Behavioural isolation may lead to complete speciation when partial postzygotic isolation acts in ... more Behavioural isolation may lead to complete speciation when partial postzygotic isolation acts in the presence of divergent specific mate recognition systems. These conditions exist where Mus musculus musculus and M. m. domesticus come into contact and hybridize. We studied two mate recognition signal systems, based on urinary and salivary proteins, across a Central European portion of the mouse hybrid zone. Introgression of the genomic regions responsible for these signals: the major urinary proteins (MUPs) and androgen binding proteins (ABPs) respectively, was compared to introgression at loci assumed to be nearly neutral and those under selection against hybridization. The preference of individuals taken from across the zone regarding these signals was measured in Y mazes, and we develop a model for the analysis of the transition of such traits under reinforcement selection. The strongest assortative preferences were found in males for urine and females for ABP. Clinal analyses confirm nearly neutral introgression of an Abp locus and two loci closely linked to the Abp gene cluster whereas two markers flanking the Mup gene region reveal unexpected introgression. Geographic change in the preference traits matches our reinforcement selection model significantly better than standard cline models. Our study confirms that behavioural barriers are important components of reproductive isolation between the house mouse subspecies
Hybrid zones have long been described as “windows on the evolutionary process”, and studying them... more Hybrid 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 musculusandMus 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.musculusordomesticus) 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 eithermusculusordomesticusgenomes across the hybrid zone. In three cases, the highest and...
The longstanding impression that hybrid mice are more highly parasitized and therefore less fit t... more 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 byEimeria, a parasite of high pathogenicity, and infections by pinworms, assumed to be less pathogenic. ForEimeriawe 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 couldn’t show such an effect. We c...
A synopsis of cytogenetic studies performed on various species and populations of myoxids is pres... more A synopsis of cytogenetic studies performed on various species and populations of myoxids is presented. Interspecific phylogenetic relationships derived from chromosomal data are evaluated and the evolutionary importance of intraspecific karyotypic variation is discussed. New data on the karyotypes of Dtyomys nifedula from Asia and Muscardinus avellanarius from Europe are presented and discussed with special emphasis on the contrasting pattern of chromosomal differentiation in Eliornys vs. Dryomys and other myoxids. A bibliography of myoxid cytogenetics and karyology is compiled. RIASSUNTO-Variazione cromosomica e sistematica dei Mioxidi-Viene presentata una sinossi degli studi citogenetici effettuati su varie specie e popolazioni di Mioxidi. Vengono valutate le relazioni filogenetiche interspecifiche derivate da dati cromosomici e viene discussa l'importanza evolutiva della variazione cariotipica intraspecifica. Vengono presentati nuovi dati sui cariotipi di Dryomys nitedula as...
According to Haldane’s rule, sex chromosomes should harbour more incompatibilities than autosomes... more According to Haldane’s 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...
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