P. pacificus mutation rate variation

Mutation is the major force of evolution, and its accumulation is suggested to be influenced by environmental and genetic factors in both unicellular and multicellular species. While ample evidence showed the effect of temperature as an environmental factor on the rate of mutation, the influence of diet is less well characterized, especially in multicellular species. Here, we present the mutation accumulation (MA) rate difference of the same nematode species from different genetic backgrounds on various kinds of bacterial diets. The mutation rates were estimated from whole-genome sequencing data of MA lines of different natural isolates of the free-living nematode Pristionchus pacificus on various bacterial diets isolated from the wild. We observed mutation rate difference among different different bacterial diets. All bacteria were originally isolated from the natural habitats of P. pacifcus and have the potential to influence the nematodes in the wild. While the mutation rate changed, the mutation spectra are similar, leaving similar accessible mutations under varying conditions. Overall, our results demonstrate that environmental factors can influence the mutation rate, and further that rate changes occur without drastic changes in other mutational features.