Noncanonical DNA structures are drivers of genome evolution

In addition to the canonical right-handed double helix, other DNA structures, termed 'non-B DNA', can form in the genomes across the tree of life. Non-B DNA regulates multiple cellular processes, including replication and transcription, yet its presence is associated with elevated mutagenicity and genome instability. These discordant cellular roles fuel the enormous potential of non-B DNA to drive genomic and phenotypic evolution. Here we discuss recent studies establishing non-B DNA structures as novel functional elements subject to natural selection, affecting evolution of transposable elements (TEs), and specifying centromeres. By highlighting the contributions of non-B DNA to repeated evolution and adaptation to changing environments, we conclude that evolutionary analyses should include a perspective of not only DNA sequence, but also its structure.

Automated summary

In addition to the canonical right-handed double helix, non-B DNA structures can form in the genomes across the tree of life. These structures regulate cellular processes and have the potential to drive genomic and phenotypic evolution. Recent studies have established non-B DNA as novel functional elements subject to natural selection, affecting the evolution of transposable elements and centromeres. Evolutionary analyses should consider not only DNA sequence, but also its structure.