Some researchers in Australia think they have found an epigenetic link between a father's poor diet and subsequent metabolic problems in their daughters, according to an October 2010 article in the journal Nature.
In the study, the researchers fed rats (the "fathers") a diet that was designed to make them obese. A control group of rats were not made obese. They then studied the offspring of the two groups of fathers, and found that the daughters of the male obese rats were born with cellular dysfunctions in the pancreatic β-cells, which are central to insulin and weight control.
The father had passed the acquired obesity on to the daughters (note the "acquired" part).
Epigenetics refers to a vast layer of cell signaling that exists above the genes ("epi" being the Greek for "above"). Environmental triggers or lifestyle factors can thus positively or negatively express, or "turn on or off," your genes. The DNA sequence remains unchanged, but the "behavior" of the gene changes, and these changes can apparently be passed on. Yikes! That's a rather astounding concept and finding.
The genes are the words and the epigenome is the grammar, as one scientist put it.
From the nature.com site:
Glucose levels in the body are controlled by insulin, produced by groups of β-cells in the pancreas. These cells group to form 'islets'. The team noticed that in the daughters of fat fathers, these islets had shrunk, compared with those of the control daughters.
The next step was to investigate what was causing these changes. The daughters of the obese male rats showed an altered expression of more than 600 pancreatic islet genes. But because the DNA code itself remained unchanged, Morris's team suggest that the changes in gene expression are epigenetic.
The researchers found the greatest difference in expression in a gene called Il13ra2. A gene's expression can be altered by methylation, in which methyl groups are added to the DNA, effectively 'silencing' the gene. But in the daughters of obese fathers, the level of methylation of this gene was around 25% of the level seen in the control daughters.
Studying the "epigenome" is a giant and important area of research. Epigenetics suggests that it matters less what genes you're born with than the positive expression of those genes with environmental cues, meaning your fitness routine, diet, and stress levels.