3D Map of DNA Within Retinal CellsResearchers in the United States have created a 3D map of DNA organisation within human retinal cells. The research provides new insight into regulation of gene expression in general, and in retinal function, in both rare and common eye diseases. The study has been published in Nature Communications. The National Eye Institute researchers mapped the organisation of human retinal cell chromatin, the fibres that package three billion nucleotide-long DNA molecules into compact structures that fit into chromosomes within each cell’s nucleus. “This is the first detailed integration of retinal regulatory genome topology with genetic variants associated with age-related macular degeneration (AMD) and glaucoma,” said the study’s lead investigator, Dr Anand Swaroop. Using deep Hi-C sequencing, a tool used for studying 3D genome organisation, the researchers created a high-resolution map that included 704 million contact points within retinal cell chromatin. Maps were constructed using postmortem retinal samples from four human donors. The researchers integrated the chromatin topology map with data on genetic variants identified for their involvement in AMD and glaucoma, two leading causes of vision loss and blindness. The findings point to specific candidate causal genes involved in those diseases. The integrated genome regulatory map will also assist in evaluating genes associated with other common retina-associated diseases such as diabetic retinopathy, determining missing heritability and understanding genotypephenotype correlations in inherited retinal and macular diseases.