St. Louis, MO, USA. A method called comparative epigenomics uses interspecies comparison of DNA and histone modifications for in-depth annotation of the regulatory genome.

So far, sequencing of the human genome has provided a wealth of genetic information, but the goal of cataloguing the specific functions of every gene (and the collective interactions of all genes) has remained elusive.


While the genome of an organism contains all its genes, it is the epigenome that decides which are expressed (or turned on). Though genomic science has long focused on comparative genomics — comparing the genomes of similar species and finding the commonalities to determine how common traits are regulated — comparative epigenetics is intended as a more in-depth look at regulatory functions.


Click Pic for DetailsThe researchers were led by Sheng Zhong, of the Institute for Genomic Biology and Department of Bioengineering at the University of Illinois. Zhong collaborated with Ting Wang at Washington University in St. Louis, Harris Lewin, and Franklin West at the University of Georgia. They focused their work on three species: humans, mice, and pigs.

By analyzing 9 epigenomic marks in pluripotent stem cells, they were able to create an epigenomic map for each which they could then compare. The findings appear in the journal Cell.

The research team concluded that, with proper analysis procedures, traces of interspecies epigenomic conservation could be identified. They then demonstrated that the conserved epigenetic markers can be effectively used to annotate the genome, clarifying the genome's regulatory function.

Understanding the genome is one of the most pressing problems for science, and the investigators believe their study findings shed light on a promising alternative method. "Comparative epigenomics enables us to find more clues from evolution about the functions of our genomes," adds Zhong.