Deserts typically stir up images of desolate landscapes sprinkled with cacti, but according to a new report, ‘methylation deserts’, the 1% of the genome with the lowest occurrence of DNA methylation, are actually fertile ground for structural genomic mutations.
A research group from the Baylor College of Medicine knew that the human genome contains many loci where mutations occur, including events like insertions and deletions within the chromosome. This source of variation is linked to both evolution and human disease, but scientists aren’t sure exactly how, so they took a deeper dive into the issue using evolutionary analyses. The link between DNA repeated in low-copy numbers (LCRs), and DNA hypomethylation, which are both implicated with structural mutability in separate cases, was investigated and here’s what they learned:
- LCRs were confirmed as promoters of structural mutability in the genome.
- Genomic instability was found to be heavily associated with DNA hypomethylation, and methylation deserts in particular.
- Methylation deserts had 10-times the amount of structural mutations compared to the genome-wide average.
- Structural mutations in individuals with schizophrenia, bipolar disorder, developmental delay, and autism were significantly enriched within hypomethylated regions.
The Baylor team suggests that they have revealed a new connection between genomic DNA methylation and mutability with evolution, and human diseases.
Quench your thirst for more structural genomic mutation knowledge at PLoS Genetics, May 2012.