Still, recent studies in mice and rats have fueled the controversy. Richards cited "a whole new world called nutritional epigenomics," where researchers are trying to influence epigenetic information by of all things diet. In a study with mice hybrids, researchers provided pregnant moms with varying levels of folate and B vitamins, to affect DNA methylation.
"The idea was : If you pump these pregnant moms up with these dietary supplements, you might be able to skew the DNA methylation patterns, and thus skew the way the mice come out at the end of the day, and it works,'" Richards says. "In this particular instance that says what you're getting fed in the womb influences your phenotype ?physical and physiological attributes."
Another study showed that early grooming and nurturing of rat pups by rat moms affects methylation of a glucocorticoid receptor gene in the hippocampus in the brain. If the pups get lots of nurturing the glucocorticoid gene gets turned on and expressed early at a critical period, providing pups the beneficial outcome to handle stress later in life. Not enough nurturing and grooming, and the gene never gets turned on. Richards says that whole mechanism appears to be the result of changes in DNA methylation associated with changes in DNA packaging.
"These studies do not demonstrate inheritance between generations, but they do show that the early nutritional environment in the mice and early behavioral environment in the rat studies can change the DNA packaging on the genome, and that that is 'remembered' in the cell divisions that make the rest of the organism, " Richards says. "But this is not from one generation to another. No one has shown that yet.
"To get to the issue of the more extreme variations of soft inheritance, it has to be determined whether the environment can induce an epigenetic
Source:Washington University in St. Louis