Genotype frequency dynamics in finite-sized, partially clonal population with mutation

Most eukaryotes reproduce using partial clonality, for which appropriate population genetic models remain limited. This gap constrains our ability to accurately reconstruct past population dynamics, predict future trajectories, and infer the evolutionary processes involved. We present a Wright-Fisher-like model tailored for tracking the mean and the variance of genotype frequencies over generations at one locus with multiple alleles in a same finite-sized population with mutation. Different initial conditions and rates of clonality generate unique mean trajectories of genotype frequencies. Partially clonal populations converge to the same unique stable equilibrium as exclusively sexual populations, that only depends on the reciprocal mutation rates between alleles. The dynamics unfold in two phases: First, genotype frequencies move towards Hardy-Weinberg proportions; Then iterate along the Hardy-Weinberg proportions until reaching the stable equilibrium. Mean allele frequencies and gene diversity remain unchanged by different rates of clonality along the trajectories. Instead, clonality influences the speed at which populations return to Hardy-Weinberg proportions and thus shapes the temporal sequence of genotype frequency distributions over generations. Variance around each mean trajectory depends only on parental genotype frequency distributions and population size, not on clonality. Taken together, these explain why both negative and positive Fis values are expected in partially clonal populations, and why variance of Fis across loci is a reliable proxy for inferring clonal rates. Our model will enable the analysis and prediction of changes in genotype frequencies within monitored populations, and will support future inference methods relying on time-series genotyping data from a target population. HighlightsO_LIOut of equilibrium, sexual and clonal populations share the same two-step dynamics. C_LIO_LIFirst, return to Hardy-Weinberg parabola impacted by rates of clonality; Then, iteration along this parabola until reaching equilibrium that only depends on mutation rates C_LIO_LIIncreasing clonality change the speed and direction of mean dynamics out of Hardy-Weinberg parabola without affecting mean allele frequencies C_LIO_LIVariance around mean dynamics depends on parental genotype frequencies and population size but not affected by clonality C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=98 SRC="FIGDIR/small/717696v1_ufig1.gif" ALT="Figure 1"> View larger version (13K): org.highwire.dtl.DTLVardef@3fe977org.highwire.dtl.DTLVardef@1f8a38eorg.highwire.dtl.DTLVardef@b9ebbaorg.highwire.dtl.DTLVardef@231c67_HPS_FORMAT_FIGEXP M_FIG C_FIG