Mus Musculus Domesticus Research Articles

Ancient mitochondrial DNA connects house mice in the British Isles to trade across Europe over three millennia

BackgroundThe earliest records in Britain for the western European house mouse (Mus musculus domesticus) date from the Late Bronze Age. The arrival of this commensal species in Britain is thought to be related to human transport and trade with continental Europe. In order to study this arrival, we collected a total of 16 ancient mouse mandibulae from four early British archaeological sites, ranging from the Late Bronze Age to the Roman period.ResultsFrom these, we obtained ancient mitochondrial DNA (mtDNA) house mouse sequences from eight house mice from two of the sites dating from the Late Bronze to Middle Iron Age. We also obtained five ancient mtDNA wood mouse (Apodemus spp.) sequences from all four sites. The ancient house mouse sequences found in this study were from haplogroups E (N = 6) and D (N = 2). Modern British house mouse mtDNA sequences are primarily characterised by haplogroups E and F and, much less commonly, haplogroup D.ConclusionsThe presence of haplogroups D and E in our samples and the dating of the archaeological sites provide evidence of an early house mouse colonisation that may relate to Late Bronze Age/Iron Age trade and/or human expansion. Our results confirm the hypothesis, based on zooarchaeological evidence and modern mtDNA predictions, that house mice, with haplogroups D and E, were established in Britain by the Iron Age and, in the case of haplogroup E, possibly as early as the Late Bronze Age.

Gene expression plasticity and desert adaptation in house mice.

Understanding how organisms adapt to new environments is a key problem in evolution, yet it remains unclear whether phenotypic plasticity generally facilitates or hinders this process. Here we studied evolved and plastic responses to water-stress in lab-born descendants of wild house mice (Mus musculus domesticus) collected from desert and non-desert environments and measured gene expression and organismal phenotypes under control and water-stressed conditions. After many generations in the lab, desert mice consumed significantly less water than mice from other localities, indicating that this difference has a genetic basis. Under water-stress, desert mice maintained more weight than non-desert mice, and exhibited differences in blood chemistry related to osmoregulatory function. Gene expression in the kidney revealed evolved differences between mice from different environments as well as plastic responses between hydrated and dehydrated mice. Desert mice showed reduced expression plasticity under water-stress compared to non-desert mice. Importantly, non-desert mice under water-stress generally showed shifts toward desert-like expression, consistent with adaptive plasticity. Finally, we identify several co-expression modules linked to phenotypes of interest. These findings provide evidence for local adaptation after a recent invasion and suggest that adaptive plasticity may have facilitated colonization of the desert environment.

Replacement of surgical vasectomy through the use of wild-type sterile hybrids.

For the production and rederivation of mouse strains, pseudopregnant female mice are used for embryo transfer and serve as surrogate mothers to support embryo development to term. Vasectomized males are commonly used to render pseudopregnancy in females, generated by surgical procedures associated with considerable pain and discomfort. Genetically modified mouse strains with a sterility phenotype provide a non-surgical replacement and represent an important application of the 3Rs (Replacement, Reduction, Refinement). However, the maintenance of such genetically modified mouse strains requires extensive breeding and genotyping procedures, which are regulated procedures under national legislation. As an alternative, we have explored the use of sterile male hybrids that result when two wild-type mouse subspecies, Mus musculus musculus and Mus musculus domesticus, interbreed. We find the male STUSB6F1 hybrid, resulting from the mating of female STUS/Fore with male C57BL/6J, ideally suited and demonstrate that its performance for the production of oviduct and uterine transfer recipients is indistinguishable when compared to surgically vasectomized mice. The use of these sterile hybrids avoids the necessity for surgical procedures or the breeding of sterile genetically modified lines and can be generated by the simple mating of two wild-type laboratory strains-a non-regulated procedure. Furthermore, in contrast with the breeding of genetically sterile mice, all male offspring are sterile and suitable for the generation of pseudopregnancy, allowing their efficient production with minimal breeding pairs.

The mice’s hematological effect of given the Staphylococcus aureus and Persea americana

Staphylococcus aureus is often the cause of various diseases and food poisoning in animals and humans. Avocado seeds (Persea americana, Mill) contain important compounds that have antimicrobial activity. This study aimed to observe the hematological dynamics of mice (Mus musculus domesticus) infected with S. aureus and induced by P. americana extract. BALB/c male mice aged 12 weeks were divided into 6 groups of 5 in each group, named K-1, K-2, K-3, K-4, K-5, and K-6. All groups were infected with S. aureus 1x108 CFU cell/mL intraperitoneally (IP) on day 0. After the blood sample was taken, then K-1 was given a single dose of tetracyclin 130 mg/kg BW, K-2 was given 130 mg/kb BW oferythromycin, K-3 was given aquabidest (placebo), K-4 was given P. americana extract 300 mg/kg BW, K-5 at a dose 600 mg/kg BW and K-6 at a dose 1200 mg/kg BW. The treatment was given for 7 consecutive days, then a second blood sample was taken and analyzed with the VetScan-HM5 analyzer and interpreted. It was concluded that S. aureus infection caused leukopenia and was potentially followed by lymphopenia, neutrophilia, and monocytosis. The occurrence of microcytosis can lead to anemia, which can be categorized as microcytic hypochromic or normocytic normochromic. Administration of P. americana extract at a dose 300 mg/kg BW (K-4) for 7 days after S. aureus infection was found to be effective in improving hematological values in mice back to normal.

Rapid colonisation, breeding and successful recruitment of eastern barn owls (

Abstract Context The introduced house mouse (Mus domesticus) causes significant economic damage to Australia’s agricultural enterprises. As part of the Marna Banggara Rewilding Project on the southern Yorke Peninsula (SYP), the present study focused on the eastern barn owl (Tyto alba delicatula) as a potential bio-controller of mice, by providing nesting spaces where natural hollows are limited. Aims To design an appropriate pole-mounted wooden nest box, and to enhance barn-owl-breeding and house-mouse-hunting capacity on farmland adjacent to remnant native vegetation. Methods A prototype nest box was collaboratively designed with a nest box manufacturer using data from previous barn owl studies and anecdotal reports. Eleven pole-mounted wooden boxes with platforms were installed at distances >1.4 km apart on properties near Warooka, southern Yorke Peninsula (SYP), and monitored over a 6-month period using external trail cameras. Key results Of the 11 nest boxes installed, 55 percent were colonised within a month after establishment, and 82 percent were colonised within 7 months. Occupied nest boxes were actively used by paired owls for mating, breeding and rearing of chicks, which resulted in up to 35 fledgling owlets. Conclusions The nest box design successfully supported eastern barn owl colonisation and reproduction on the SYP. The inclusion of the platform not only provided easy, minimally invasive monitoring of barn owl activity and prey intake by researchers, but also increased usable space for barn owl behaviours, such as copulation and wing flapping. Implications The important nest box design elements featured in this paper, such as the platform, high entrance hole, predator-proof pole and rear door access, can be implemented in barn owl conservation, research and on farms where alternative nesting sites are limited.

Efficacy of a combined insecticide-rodenticide product on ectoparasite and commensal rodent mortality.

Ectoparasites may transfer zoonotic pathogens from rodents to humans or livestock when rodents are managed with rodenticides. This could be minimized using a product combining a rodenticide with a delayed action and a systemic insecticide/acaricide that rapidly kills ectoparasites. Such a combination was tested in commensal pest rodent species to assess efficacy and timing of responses in rodents, and fleas and ticks feeding on them. Ticks or fleas attached to rats (Rattus norvegicus) and house mice (Mus musculus domesticus) were exposed to a product containing brodifacoum (50 ppm) and fipronil (40 ppm) for three days. 98-100% of fleas on treated rodents died within one to two days after first exposure, whereas >90% fleas survived on control rodents. The effect persisted for four or more days after bait uptake. Ticks started to succumb to the effect of the combination product within one day (mice) and within four days (rats) of first exposure, with all ticks dying by Day (D)8. Tick survival in control rodents was 90-100%. Rodent mortality began at D3 (rats) and D4 (mice) after first consumption of product and all were dead by D9 (rats) and D7 (mice). This product effectively killed ectoparasites and rodents. Flea mortality was swift and complete, generally within one day of exposure, whereas it took ticks up to four days to die, but before the rats and house mice died. The combination product might help to prevent ectoparasites migrating from dying rodents to another host. Field trials are warranted. © 2020 Society of Chemical Industry.

Haldane's rule in the placenta: Sex‐biased misregulation of the Kcnq1 imprinting cluster in hybrid mice

Hybrid phenotypes that contribute to postzygotic reproductive isolation often exhibit pronounced asymmetry, both between reciprocal crosses and between the sexes in accordance with Haldane's rule. Inviability in mammalian hybrids is associated with parent-of-origin placental growth abnormalities for which misregulation of imprinted gene (IGs) is the leading candidate mechanism. However, direct evidence for the involvement of IGs in hybrid growth dysplasia is limited. We used transcriptome and reduced representation bisulfite sequencing to conduct the first genome-scale assessment of the contribution of IGs to parent-of-origin placental growth dysplasia in the cross between the house mouse (Mus musculus domesticus) and the Algerian mouse (Mus spretus). IGs with transgressive expression and methylation were concentrated in the Kcnq1 cluster, which contains causal genes for prenatal growth abnormalities in mice and humans. Hypermethylation of the cluster's imprinting control region, and consequent misexpression of the genes Phlda2 and Ascl2, is a strong candidate mechanism for transgressive placental undergrowth. Transgressive placental and gene regulatory phenotypes, including expression and methylation in the Kcnq1 cluster, were more extreme in hybrid males. Although consistent with Haldane's rule, male-biased defects are unexpected in rodent placenta because the X-chromosome is effectively hemizygous in both sexes. In search of an explanation, we found evidence of leaky imprinted (paternal) X-chromosome inactivation in hybrid female placenta, an epigenetic disturbance that may buffer females from the effects of X-linked incompatibilities to which males are fully exposed. Sex differences in chromatin structure on the X and sex-biased maternal effects are nonmutually exclusive alternative explanations for adherence to Haldane's rule in hybrid placenta. The results of this study contribute to understanding the genetic basis of hybrid inviability in mammals, and the role of IGs in speciation.

Chromosome-wide characterization of meiotic noncrossovers (gene conversions) in mouse hybrids.

During meiosis, the recombination-initiating DNA double-strand breaks (DSBs) are repaired by crossovers or noncrossovers (gene conversions). While crossovers are easily detectable, noncrossover identification is hampered by the small size of their converted tracts and the necessity of sequence polymorphism. We report identification and characterization of a mouse chromosome-wide set of noncrossovers by next-generation sequencing of 10 mouse intersubspecific chromosome substitution strains. Based on 94 identified noncrossovers, we determined the mean length of a conversion tract to be 32 bp. The spatial chromosome-wide distribution of noncrossovers and crossovers significantly differed, although both sets overlapped the known hotspots of PRDM9-directed histone methylation and DNA DSBs, thus supporting their origin in the standard DSB repair pathway. A significant deficit of noncrossovers descending from asymmetric DSBs proved their proposed adverse effect on meiotic recombination and pointed to sister chromatids as an alternative template for their repair. The finding has implications for the molecular mechanism of hybrid sterility in mice from crosses between closely related Mus musculus musculus and Mus musculus domesticus subspecies.

Coupling between tolerance and resistance for two related Eimeria parasite species.

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).

Genetic Basis of Aerobically Supported Voluntary Exercise: Results from a Selection Experiment with House Mice.

The biological basis of exercise behavior is increasingly relevant for maintaining healthy lifestyles. Various quantitative genetic studies and selection experiments have conclusively demonstrated substantial heritability for exercise behavior in both humans and laboratory rodents. In the "High Runner" selection experiment, four replicate lines of Mus domesticus were bred for high voluntary wheel running (HR), along with four nonselected control (C) lines. After 61 generations, the genomes of 79 mice (9-10 from each line) were fully sequenced and single nucleotide polymorphisms (SNPs) were identified. We used nested ANOVA with MIVQUE estimation and other approaches to compare allele frequencies between the HR and C lines for both SNPs and haplotypes. Approximately 61 genomic regions, across all somatic chromosomes, showed evidence of differentiation; 12 of these regions were differentiated by all methods of analysis. Gene function was inferred largely using Panther gene ontology terms and KO phenotypes associated with genes of interest. Some of the differentiated genes are known to be associated with behavior/motivational systems and/or athletic ability, including Sorl1, Dach1, and Cdh10 Sorl1 is a sorting protein associated with cholinergic neuron morphology, vascular wound healing, and metabolism. Dach1 is associated with limb bud development and neural differentiation. Cdh10 is a calcium ion binding protein associated with phrenic neurons. Overall, these results indicate that selective breeding for high voluntary exercise has resulted in changes in allele frequencies for multiple genes associated with both motivation and ability for endurance exercise, providing candidate genes that may explain phenotypic changes observed in previous studies.

Differential immune gene expression associated with contemporary range expansion in two invasive rodents in Senegal

Biological invasions are major anthropogenic changes associated with threats to biodiversity and health. However, what determines the successful establishment and spread of introduced populations remains unclear. Here, we explore several hypotheses linking invasion success and immune phenotype traits, including those based on the evolution of increased competitive ability concept. We compared gene expression profiles between anciently and recently established populations of two major invading species, the house mouse Mus musculus domesticus and the black rat Rattus rattus, in Senegal (West Africa). Transcriptome analyses identified differential expression between anciently and recently established populations for 364 mouse genes and 83 rat genes. All immune-related genes displaying differential expression along the mouse invasion route were overexpressed at three of the four recently invaded sites studied. Complement activation pathway genes were overrepresented among these genes. By contrast, no particular immunological process was found to be overrepresented among the differentially expressed genes of black rat. Changes in transcriptome profiles were thus observed along invasion routes, but with different specific patterns between the two invasive species. These changes may be driven by increases in infection risks at sites recently invaded by the house mouse, and by stochastic events associated with colonization history for the black rat. These results constitute a first step toward the identification of immune eco-evolutionary processes potentially involved in the invasion success of these two rodent species.

Social status and ejaculate composition in the house mouse.

Sperm competition theory predicts that males should tailor ejaculates according to their social status. Here, we test this in a model vertebrate, the house mouse (Mus musculus domesticus), combining experimental data with a quantitative proteomics analysis of seminal fluid composition. Our analyses reveal that both sperm production and the composition of proteins found in seminal vesicle secretions differ according to social status. Dominant males invested more in ejaculate production overall. Their epididymides contained more sperm than those of subordinate or control males, despite similar testes size between the groups. Dominant males also had larger seminal vesicle glands than subordinate or control males, despite similar body size. However, the seminal vesicle secretions of subordinate males had a significantly higher protein concentration than those of dominant males. Moreover, detailed proteomic analysis revealed subtle but consistent differences in the composition of secreted seminal vesicle proteins according to social status, involving multiple proteins of potential functional significance in sperm competition. These findings have significant implications for understanding the dynamics and outcome of sperm competition, and highlight the importance of social status as a factor influencing both sperm and seminal fluid investment strategies.This article is part of the theme issue ‘Fifty years of sperm competition’.

Baculum shape and paternity success in house mice: evidence for genital coevolution.

Sexual selection is believed to be responsible for the rapid divergence of male genitalia, which is a widely observed phenomenon across different taxa. Among mammals, the stimulatory role of male genitalia and female 'sensory perception' has been suggested to explain these evolutionary patterns. Recent research on house mice has shown that baculum (penis bone) shape can respond to experimentally imposed sexual selection. Here, we explore the adaptive value of baculum shape by performing two experiments that examine the effects of male and female genitalia on male reproductive success. Thus, we selected house mice (Mus musculus domesticus) from families characterized by extremes in baculum shape (relative width) and examined paternity success in both non-competitive (monogamous) and competitive (polyandrous) contexts. Our analyses revealed that the relative baculum shape of competing males influenced competitive paternity success, but that this effect was dependent on the breeding value for baculum shape of the family from which females were derived. Our data provide novel insight into the potential mechanisms underlying the evolution of the house mouse baculum and lend support to the stimulatory hypothesis for the coevolution of male and female genitalia. This article is part of the theme issue 'Fifty years of sperm competition'.

Nuclear response to divergent mitochondrial DNA genotypes modulates the interferon immune response.

Mitochondrial OXPHOS generates most of the energy required for cellular function. OXPHOS biogenesis requires the coordinated expression of the nuclear and mitochondrial genomes. This represents a unique challenge that highlights the importance of nuclear-mitochondrial genetic communication to cellular function. Here we investigated the transcriptomic and functional consequences of nuclear-mitochondrial genetic divergence in vitro and in vivo. We utilized xenomitochondrial cybrid cell lines containing nuclear DNA from the common laboratory mouse Mus musculus domesticus and mitochondrial DNA (mtDNA) from Mus musculus domesticus, or exogenous mtDNA from progressively divergent mouse species Mus spretus, Mus terricolor, Mus caroli and Mus pahari. These cybrids model a wide range of nuclear-mitochondrial genetic divergence that cannot be achieved with other research models. Furthermore, we used a xenomitochondrial mouse model generated in our laboratory that harbors wild-type, C57BL/6J Mus musculus domesticus nuclear DNA and homoplasmic mtDNA from Mus terricolor. RNA sequencing analysis of xenomitochondrial cybrids revealed an activation of interferon signaling pathways even in the absence of OXPHOS dysfunction or immune challenge. In contrast, xenomitochondrial mice displayed lower baseline interferon gene expression and an impairment in the interferon-dependent innate immune response upon immune challenge with herpes simplex virus, which resulted in decreased viral control. Our work demonstrates that nuclear-mitochondrial genetic divergence caused by the introduction of exogenous mtDNA can modulate the interferon immune response both in vitro and in vivo, even when OXPHOS function is not compromised. This work may lead to future insights into the role of mitochondrial genetic variation and the immune function in humans, as patients affected by mitochondrial disease are known to be more susceptible to immune challenges.

Genetic structure in Orkney island mice: isolation promotes morphological diversification

Following human occupation, the house mouse has colonised numerous islands, exposing the species to a wide variety of environments. Such a colonisation process, involving successive founder events and bottlenecks, may either promote random evolution or facilitate adaptation, making the relative importance of adaptive and stochastic processes in insular evolution difficult to assess. Here, we jointly analyse genetic and morphometric variation in the house mice (Mus musculus domesticus) from the Orkney archipelago. Genetic analyses, based on mitochondrial DNA and microsatellites, revealed considerable genetic structure within the archipelago, suggestive of a high degree of isolation and long-lasting stability of the insular populations. Morphometric analyses, based on a quantification of the shape of the first upper molar, revealed considerable differentiation compared to Western European populations, and significant geographic structure in Orkney, largely congruent with the pattern of genetic divergence. Morphological diversification in Orkney followed a Brownian motion model of evolution, suggesting a primary role for random drift over adaptation to local environments. Substantial structuring of human populations in Orkney has recently been demonstrated, mirroring the situation found here in house mice. This synanthropic species may thus constitute a bioproxy of human structure and practices even at a very local scale.

Functional signatures of evolutionarily young CTCF binding sites

BackgroundThe introduction of novel CTCF binding sites in gene regulatory regions in the rodent lineage is partly the effect of transposable element expansion, particularly in the murine lineage. The exact mechanism and functional impact of evolutionarily novel CTCF binding sites are not yet fully understood. We investigated the impact of novel subspecies-specific CTCF binding sites in two Mus genus subspecies, Mus musculus domesticus and Mus musculus castaneus, that diverged 0.5 million years ago.ResultsCTCF binding site evolution is influenced by the action of the B2-B4 family of transposable elements independently in both lineages, leading to the proliferation of novel CTCF binding sites. A subset of evolutionarily young sites may harbour transcriptional functionality as evidenced by the stability of their binding across multiple tissues in M. musculus domesticus (BL6), while overall the distance of subspecies-specific CTCF binding to the nearest transcription start sites and/or topologically associated domains (TADs) is largely similar to musculus-common CTCF sites. Remarkably, we discovered a recurrent regulatory architecture consisting of a CTCF binding site and an interferon gene that appears to have been tandemly duplicated to create a 15-gene cluster on chromosome 4, thus forming a novel BL6 specific immune locus in which CTCF may play a regulatory role.ConclusionsOur results demonstrate that thousands of CTCF binding sites show multiple functional signatures rapidly after incorporation into the genome.

Further resolution of the house mouse (Mus musculus) phylogeny by integration over isolation-with-migration histories

BackgroundThe three main subspecies of house mice, Mus musculus castaneus, Mus musculus domesticus, and Mus musculus musculus, are estimated to have diverged ~ 350-500KYA. Resolution of the details of their evolutionary history is complicated by their relatively recent divergence, ongoing gene flow among the subspecies, and complex demographic histories. Previous studies have been limited to some extent by the number of loci surveyed and/or by the scope of the method used. Here, we apply a method (IMa3) that provides an estimate of a population phylogeny while allowing for complex histories of gene exchange.ResultsResults strongly support a topology with M. m. domesticus as sister to M. m. castaneus and M. m. musculus. In addition, we find evidence of gene flow between all pairs of subspecies, but that gene flow is most restricted from M. m. musculus into M. m. domesticus. Estimates of other key parameters are dependent on assumptions regarding generation time and mutation rate in house mice. Nevertheless, our results support previous findings that the effective population size, Ne, of M. m. castaneus is larger than that of the other two subspecies, that the three subspecies began diverging ~ 130 - 420KYA, and that the time between divergence events was short.ConclusionsJoint demographic and phylogenetic analyses of genomic data provide a clearer picture of the history of divergence in house mice.

A VKORC1-based SNP survey of anticoagulant rodenticide resistance in the house mouse, Norway rat and roof rat in the USA.

We conducted a vitamin K epoxide reductase subcomponent 1 (Vkorc1)-based nonsynonymous Single Nucleotide Polymorphism (nsSNP) screen with focus on the house mouse (Mus musculus domesticus), but that also considered the Norway rat (Rattus norvegicus) and roof rat (R. rattus) in the USA. We detected six Vkorc1 nsSNPs underlying the amino-acid polymorphisms Ala21Thr, Trp59Leu, Ile104Val, Val118Leu, Leu128Ser and Tyr139Cys in house mice (average coverage/SNP; n = 182 individuals), two nsSNPs underlying Arg35Pro and Gly46Ser in the Norway rat (n = 93), with the notable absence of Tyr139Cys (n = 179), and one nsSNP underlying Tyr25Phe in the roof rat (n = 27). Inferred resistance frequency is 29.1% for mice (variability of states 0-98.8%), 6.5% (0-33.3%) for the Norway rat, and 39.3% (0-52.6%) for the roof rat based on Tyr25Phe frequencies. Resistance detected in the USA in the 1980s likely was the consequence of Vkorc1 mutations in mice (Leu128Ser and Tyr139Cys), Norway rats (Arg35Pro) and roof rats (Tyr25Phe). Patterns of variant sharing between the USA and Europe indicate the importance of convergent evolution and gene flow in spreading resistance. The spread of nsSNPs in mice between continents appears to have been more effective than in Norway rats. We hypothesize that Arg35Pro may have originated in Norway rats in the USA, whereas Tyr139Cys variants originated in Europe. Tyr25Phe is the likely cause for resistance in roof rats. Further genetic testing in the USA is required to close sampling gaps, and population genomic data are needed to study the origin and spread of this adaptive trait.

Transmission of food preference via faeces in male and female house mice: Who is a good provider of food cues?

The social transmission of food preference (STFP) is a phenomenon that allows rodents to use food information perceived from their conspecifics to guide their own food choices. This social information can be collected via olfactory cues, during direct social interactions, or indirectly, via faeces left in the environment by individuals. Although reducing the risks associated with a social confrontation, faeces also convey different types of information about traits and states of individuals which could affect the indirect STFP. Here, we evaluated in the house mouse, Mus musculus domesticus, which conspecifics could be good providers of food cues for indirect STFP. Our results indicated that female mice acquire an indirect STFP from faeces of adult females, familiar or not and from faeces of adult unfamiliar males. On the contrary, males do not establish an indirect STFP from faeces of males, whether they are familiar or not, nor from those of unfamiliar females. Indirect STFP was however effective in males when the faeces were those of an unfamiliar juvenile male. A prior habituation to the odour of an unfamiliar female allowed the establishment of indirect STFP in males. Conversely, the presence of faeces of another adult male during the presentation of faeces of an accustomed female precluded the acquisition of indirect STFP in males. This study suggested that in the context of the indirect STFP, females prioritize socio-olfactory information relative to food, whereas food cues were not priority information for males. Under these conditions, females appear to be the best vectors for disseminating food information within the population. These results are discussed according to the socio-spatial organization of the species.

Long-term overlap of social and genetic structure in free-ranging house mice reveals dynamic seasonal and group size effects.

Associating with relatives in social groups can bring benefits such as reduced risk of aggression and increased likelihood of cooperation. Competition among relatives over limited resources, on the other hand, can induce individuals to alter their patterns of association. Population density might further affect the costs and benefits of associating with relatives by altering resource competition or by changing the structure of social groups; preventing easy association with relatives. Consequently, the overlap between genetic and social structure is expected to decrease with increasing population size, as well as during times of increased breeding activity. Here, we use multi-layer network techniques to quantify the similarity between long-term, high resolution genetic, and behavioral data from a large population of free-ranging house mice (Mus musculus domesticus), studied over 10 years. We infer how the benefit of associating with genetically similar individuals might fluctuate in relation to breeding behavior and environmental conditions. We found a clear seasonal effect, with decreased overlap between social and genetic structure during summer months, characterized by high temperatures and high breeding activity. Though the effect of overall population size was relatively weak, we found a clear decrease in the overlap between genetic similarity and social associations within larger groups. As well as longer-term within-group changes, these results reveal population-wide short-term shifts in how individuals associate with relatives. Our study suggests that resource competition modifies the trade-off between the costs and benefits of interacting with relatives.