What makes you different from everyone else on the planet may have less to do with the spelling of your genetic code than with a scattering of chemical “tags” that, like censor’s marks, render some of your genes unreadable.The code itself, after all, is 99.9 percent identical in all of us, so these peripheral elements – referred to as epigenetics – offer a plausible reason human beings come in such a variety of shapes and sizes.
As one recent paper suggested, epigenetics can explain why identical twins don’t always look identical, especially as they get older.
There’s a dynamic quality to epigenetics. Over your lifetime new chemical tags can stick to previously active genes, thus turning them off, while tags affixed from birth can occasionally fall off, activating genes that are meant to be disabled. A growing number of researchers are connecting such epigenetic shifts to cancer.
The good news is such changes are potentially reversible, says Frank Rauscher, a professor at the Wistar Institute. “For therapeutics, manipulating the epigenome is the way to go.”
Unlike genetic mutations, which permanently scramble a cell’s genetic code, epigenetic tags leave the underlying code intact.
“The old dogma was that cancer was caused by DNA damage and gene mutations,” says Jean-Pierre Issa, a researcher from the M.D. Anderson Cancer Center. But a closer look showed that cancer cells accumulate a combination of spelling errors in the DNA and inappropriate or missing epigenetic tags, he says. “This has led to a rethinking of environmental carcinogens and how diet could affect cancer and so on.”
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Filed under: bioinformatics, cancer, clinical diagnostics, clinical microarray, custom microarray, DNA microarray, drug discoverry, epigenetics, gene expression, genetics, genotyping, microarray, personalized medicine, Pharmacogenomics |