That overweight moms are more likely to have overweight babies is known, but the phenomenon hadn’t before been demonstrated in males of any species.

“It is difficult to comment on how relevant our finding might be for the current diabetes epidemic, but our data suggest that a father’s diet, or the fact that he is obese or diabetic, may influence his offspring’s risk of disease,” said neuropharmacologist Margaret Morris of Australia’s University of New South Wales.

It’s still too soon to extrapolate to humans the rodent results of Morris and her colleagues, which were published October 20 in Nature. But the results fit an emerging understanding of the role of epigenetics, or the chemical code that turns genes on and off, allowing on-the-fly adaptation to changing environmental conditions.

Epigenetic changes take place during an individual’s lifetime, but they can be passed down to children and even grandchildren. That was famously described in 1998, in a long-term study of Dutch children born during World War II famine, and epigenetic research has expanded rapidly in the last decade.

Also expanding is America’s waistline, with type 2 diabetes — the kind triggered by a poor diet and lack of activity — reaching epidemic levels.

“The dramatic increase in human metabolic disorders such as obesity and diabetes warrants considering the influence of environmental factors on the germ line,” wrote Michael Skinner, a Washington State University reproductive biologist, in a commentary accompanying the findings.

A family history of diabetes is a reliable indicator of increased disease risk. This is usually interpreted purely in terms of genetic mutations, rather than epigenetic changes.

In Morris’ study, however, it all fit together. When she compared gene expression patterns in the sperm of diabetic male mice to healthy males, she found tweaks in hundreds of genes linked to activity in the pancreas, which produces the blood sugar-regulating hormone insulin.

The males’ high-fat diet had caused pervasive cellular changes, which were then passed to their daughters. Most disturbingly, the daughters developed metabolic malfunction even when they were fed a healthy diet.

According to Morris, as-yet-unpublished research suggests that sons were similarly affected.

Morris next plans to study how the daughters’ inherited metabolic malfunction progresses with age, and whether it’s passed to their offspring as well.

The disorder “may worsen with time,” she said.

Image: Flickr, Ernest Figueras.

See Also:

• New Gene Switch Sows Epigenetic Doubts
• Gut Bacteria Cause Overeating in Mice
• No Quick Genetic Fix for Obesity
• Fight Fat With More Fat
• Infectious Obesity Findings are Full of Empty Calories

Citations: “Chronic high-fat diet in fathers programs b-cell dysfunction in female rat offspring.” By Sheau-Fang Ng, Ruby C. Y. Lin, D. Ross Laybutt, Romain Barres, Julie A. Owens & Margaret J. Morris. Nature, Volume 467 Number 7318, October 20, 2010

“Fathers’ nutritional legacy.” By Michael Skinner. Nature, Volume 467 Number 7318, October 20, 2010.

Brandon’s Twitter stream, reportorial outtakes and citizen-funded White Nose Syndrome story; Wired Science on Twitter.

Authors: Brandon Keim

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