eLife assessment
This important manuscript reveals signatures of co-evolution of two nucleosome remodeling factors, Lsh/HELLS and CDCA7, which are involved in the regulation of eukaryotic DNA methylation. The results suggest that the roles for the two factors in DNA methylation maintenance pathways can be traced back to the last eukaryotic common ancestor and that the CDC7A-HELLS-DNMT axis shaped the evolutionary retention of DNA methylation in eukaryotes. The solid evolutionary analyses form a strong basis for experimental follow-up studies. The work should be of interest to colleagues in the fields of evolutionary biology, chromatin biology and genome biology.