Asexual but not clonal: evolutionary processes in populations with automictic reproduction

mutation-selection balance, central fusion automixis 18. CC-BY-NC 4.0 International license not peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was. Abstract 19 Many parthenogenetically reproducing animals produce offspring not clonally but 20 through different mechanisms collectively referred to as automixis. Here, meiosis 21 proceeds normally but is followed by the fusion of meiotic products that restores 22 diploidy. This mechanism typically leads to a reduction in heterozygosity among the 23 offspring compared to the mother. Following a derivation of the rate at which 24 heterozygosity is lost at one and two loci, depending on the number of crossovers 25 between loci and centromere, a number of models are developed to gain a better 26 understanding of basic evolutionary processes in automictic populations. Analytical 27 results are obtained for the expected equilibrium neutral genetic diversity, mutation-28 selection balance, selection with overdominance, the rate of spread of beneficial 29 mutations, and selection on crossover rates. These results are complemented by 30 numerical investigations elucidating how associative overdominance (two off-phase 31 deleterious mutations at linked loci behaving like an overdominant locus) can in some 32 cases maintain heterozygosity for prolonged times, and how clonal interference 33 affects adaptation in automictic populations. These results suggest that although 34 automictic populations are expected to suffer from the lack of gene shuffling with 35 other individuals, they are nevertheless in some respects superior to both clonal and 36 outbreeding sexual populations in the way they respond to beneficial and deleterious 37 mutations. Implications for related genetic systems such as intratetrad mating, clonal 38 reproduction, selfing as well as different forms of mixed sexual and automictic 39 reproduction are discussed. 40 41. CC-BY-NC 4.0 International license not peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was .