- Cryptic asexual reproduction in Caenorhabditis nematodes [NEW RESULTS]Despite potential advantages of asexuality, most animal species reproduce by sex. This suggests that there are barriers that prevent asexuality arising from an obligately sexual ancestor. One such barrier is the transition from haploid to diploid maternal inheritance. Here we report that females of the normally sexual species Caenorhabditis nouraguensis can produce offspring asexually by sperm-dependent parthenogenesis (also called gynogenesis or
- Dysbiosis personalizes fitness effect of antibiotic resistance in the mammalian gut [NEW RESULTS]The fitness cost of antibiotic resistance in the absence of antibiotics is crucial to the success of suspending antibiotics as a strategy to lower resistance. Here we show that after antibiotic treatment the cost of resistance within the complex ecosystem of the mammalian gut is personalized. Using mice as an in vivo model, we find that the fitness effect of the same resistant mutation can be deleterious in a host, but neutral or even beneficial
- Genetic variation in parental effects contribute to the evolutionary potential of prey responses to predation risk [NEW RESULTS]Despite the ubiquity of parental effects and their potential impact on evolutionary dynamics, their contribution to the evolution of ecologically relevant adaptations remains poorly understood. Using quantitative genetics, here we demonstrate that parental effects contribute substantially to the evolutionary potential of larval antipredator responses in a leaf beetle (Leptinotarsa decemlineata). Previous research showed that larger L. decemlineat
- Maintenance of High Inbreeding Depression in Selfing Populations: Effects of Coupling of Early- and Late-Acting Mutations [NEW RESULTS]High estimates of inbreeding depression have been obtained in many plant populations with high selfing rates. However, deleterious mutations might be purged from such populations as a result of selfing. I developed a simulation model assuming the presence of mutations at two sets of loci, namely, early- and late-acting loci, and the selective abortion of embryos coupled with ovule overproduction. In the model, early-acting loci are expressed duri
- Female resource limitation does not make the opportunity for selection more female biased. [NEW RESULTS]Environmental and physiological conditions affect how individual variation is expressed and translated into variance in fitness, the opportunity for natural selection. Competition for limiting resources can magnify variance in fitness and therefore selection, while abundance of resources should reduce it. But even in a common environment the strength of selection can be expected to differ across the sexes, as their fitness is often limited by dif
- Coevolution alters predator life history traits, behavior and morphology in experimental microbial communities [NEW RESULTS]Predator-prey interactions are key for the dynamics of many ecosystems. An increasing body of evidence suggests that rapid evolution and coevolution can alter these interactions, with important ecological implications by acting on traits determining fitness, including reproduction, anti-predatory defense and foraging efficiency. However, most studies to date have focused only on evolution in the prey species, and the predator traits in coevolving
- Transition from background selection to associative overdominance promotes diversity in regions of low recombination [NEW RESULTS]Linked selection is a major driver of genetic diversity. Selection against deleterious mutations removes linked neutral diversity (background selection, BGS; Charlesworth et al. 1993), creating a positive correlation between recombination rates and genetic diversity. Purifying selection against recessive variants, however, can also lead to associative overdominance (AOD; Ohta 1971, Zhao & Charlesworth 2016), due to an apparent heterozygote ad
- Sex chromosomes control vertical transmission of feminizing Wolbachia symbionts in an isopod [NEW RESULTS]Microbial endosymbiosis is widespread in animals, with major ecological and evolutionary implications. Successful symbiosis relies on efficient vertical transmission through host generations. However, when symbionts negatively affect host fitness, hosts are expected to evolve suppression of symbiont effects or transmission. Here we show that sex chromosomes control vertical transmission of feminizing Wolbachia endosymbionts in the isopod Armadill
- Independent evolution towards large body size in the distinctive Faroe Island mice [NEW RESULTS]Most traits in nature involve the collective action of many genes. Traits that evolve repeatedly are particularly revealing about how selection may act on traits. In mice, large body size has evolved repeatedly on islands and under artificial selection in the laboratory. Identifying the loci and genes involved in this process may shed light on the evolution of complex, polygenic traits. Here, we have mapped the genetic basis of body size variatio
- Origins and long-term patterns of copy-number variation in rhesus macaques [NEW RESULTS]Mutations play a key role in the development of disease in an individual and the evolution of traits within species. Recent work in humans and other primates has clarified the origins and patterns of single nucleotide variants, showing that most arise in the father's germline during spermatogenesis. It remains unknown whether larger mutations, such as deletions and duplications of hundreds or thousands of nucleotides, follow similar patterns. Suc
- Phylogeny, transposable element and sex chromosome evolution of the basal lineage of birds [NEW RESULTS]Sex chromosomes of mammals and most birds are heteromorphic, while those of many paleognaths (ratites and tinamous) are inexplicably homomorphic. To dissect the mechanisms underlying the different tempo of sex chromosome evolution, we produced high-quality genomes of 12 paleognathous species, and reconstructed their phylogeny based on alignments of the non-coding sequences extending to nearly 40% of the genome. Our phylogenomic tree grouped the S
- The crustacean Armadillidium vulgare, a new promising model for the study of cellular senescence [NEW RESULTS]Senescence, the decline of physiological parameters with increasing age, is a quasi-ubiquitous phenomenon in the living world. However, the observed patterns of senescence can markedly differ between across species and populations, between sexes and even among individuals. To identify the drivers of this variation in senescence, experimental approaches are essential and involve the development of tools and new study models. In fact, current knowl
- Evolved differences in cis and trans regulation between the maternal and zygotic mRNA complements in the Drosophila embryo [NEW RESULTS]During embryogenesis in animals, initial developmental processes are driven entirely by maternally provided gene products that are deposited into the oocyte. The zygotic genome is transcriptionally activated later, when developmental control is handed off from maternal gene products to the zygote during the maternal to zygotic transition. The maternal to zygotic transition is highly regulated and conserved across all animals, and while some detai
- Antagonistic coevolution between multiple quantitative traits: Matching dynamics can arise from difference interactions [NEW RESULTS]Coevolution is one of the major drivers of complex dynamics in population ecology. Historically, antagonistic coevolution in victim-exploiter systems has been a topic of special interest, and involves traits with various genetic architectures (e.g., the number of genes involved) and effects on interactions. For example, exploiters may need to have traits that "match" those of victims for successful exploitation (i.e., a matching interaction), or
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