We cant say for certain that we identified all of them, but we think we found a large number, says Hartemink.
Jirtle, who has studied imprinting for years, notes that imprinting is an epigenetic event, meaning its something that can change a genes function without altering the sequence of its DNA. Imprinted genes are unusually vulnerable to pressures in our environment even what we eat, drink, and breathe. On top of that, epigenetic changes can be inherited. I dont think people realize that.
Several years ago, Jirtle showed that Agouti mice normally fat and yellow when fed certain dietary supplements, would produce brown, normal weight babies. The babies Agouti genes, the ones responsible for color, were the same as the mothers, yet they looked different. Thats epigenetics in action, says Jirtle.
Its estimated that imprinted genes comprise about 1 percent of the human genome, and until now, only several dozen had been identified. Using their new Rosetta stone, however, Jirtle and Hartemink found 156 new likely imprinted genes, and validated two particularly interesting ones on chromosome 8, where none had been found before. One of them, KCNK9, is mostly active in the brain, is known to cause cancer, and may also be linked to bipolar disorder and epilepsy. The second, DLGAP2, is a possible bladder cancer tumor suppressor gene.
Hartemink says experiments to confirm that all 156 new genes are truly imprinted and not just statistically likely candidates will be difficult, mostly because gene exp
|Contact: Michelle Gailiun|
Duke University Medical Center