Comment on "genomic hypomethylation in the human germline associates with selective structural mutability in the human genome"

Based on an analysis of DNA methylation patterns in human sperm, Li et al. recently reported a significant relationship between CNVs and hypomethylation in the male germline [9], leading to the suggestion that DNA hypomethylation plays a causative role in the generation of structural variation. Furthermore, given their highly repetitive and dynamic nature, loci rich in satellites are enriched for CNVs (51.7% of windows containing satellites overlap HapMap CNVs [7] compared to 20.5% in the rest of the genome), creating an inherent confounder between CNVs and hypomethylation. (b) No enrichment for CNVs in hypomethylated regions after removal of confounding genomic features.