Researchers published three major papers that map and compare the genomes and epigenomes of humans with the fly, Drosophila melanogaster, and the worm, Caenorhabditis elegans.
The genome is passed down from our parents but the eipgenome can be altered by environmental exposures and event those of parents and grandparents, a Washington University in St. Louis news release reported. The epigenome consists of chemical tags on our DNA that determine which genes are expressed or silenced.
This means it could be possible to diagnose and treat diseases caused by the deregulation of gene expression; such diseases include cancer, Alzheimer's, and diabetes. Epigenetic marks are reversible, which could lead to new therapies for deadly diseases such as cancer.
The researchers looked at epigenetic marks on the chromatin in selected cell lines and developmental stages of the fly. The genome-wide surveys mostly confirmed earlier findings, but having a comprehensive map is important in establishing the entire genome.
The researchers are also looking into neurological diseases caused by what are known as triplet repeats, a series of nucleotides repeated numerous times in an array. One of these repeats occurs in a non-coding part of a gene that makes a protein called Frataxin. In healthy people the triplet repeats up to 60 times, but it can trigger machinery that tries to silence the gene. Loss of Frataxin causes Friedreich's ataxia, a disease characterized by debilitating effects on coordination.
"What seems to be happening is that the epigenetic machinery, identifying the repeats as disruptive or aberrant DNA, tries to silence them, and ends up silencing the gene," said Sarah C. R. Elgin, the Viktor Hamburger Professor of Arts & Sciences and professor of biology at Washington University in St. Louis.
Richard Festenstein, an investigator at Imperial College, London, recently modeled Friedreich's ataxia in mice and demonstrated a similar repeat introduced to the genome would be silenced. This type of model in flies or worms could help determine how drugs and micronutrients impact the epigenome.
Sixty-six companies are currently developing 78 epigenetic therapy drugs for human cancer alone, but some researchers are concerned it could have dangerous side effects if used as chemotherapy.
"They're giving a drug to a whole person; they're not just giving it to their tumor cells. If you're going to alter the level of gene activation, you need to think about what could be the impact on other cells," Elgin said. The new model could help researchers gain insight into these impacts.
The findings were published August 28 issue of the journal Nature
