A mother’s diet leaves a lasting impact on the health of her descendants. Mice that are starved during pregnancy give birth to pups that later develop diabetes, and whose offspring are also at risk of the disease. Now a new study provides fresh evidence for the controversial idea that chemical or ‘epigenetic’ alterations to the genome — which influence gene activity, but not the DNA sequence — can transmit the effects of environmental exposures across multiple generations.
Her team looked to a strain of mice that could survive being fed 50% fewer calories than normal during late pregnancy. These mice gave birth to underweight pups, which later showed signs of diabetes, such as glucose intolerance. What’s more, the males of that generation went on to have offspring that also developed symptoms of diabetes, even though they ate normally.
From The Scientist :
Geneticist Anne Ferguson-Smith from the University of Cambridge in the U.K., along with endocrinologist Mary-Elizabeth Patti at the Joslin Diabetes Center in Boston and their colleagues, decreased by half the caloric intake of mice during their last week of pregnancy, when epigenetic reprogramming of male germ cells occurs. Assessing the genome-wide methylation state of the sperm of the first-generation sons of undernourished mothers, the researchers found that these sperm had 111 hypomethylated regions not present in the sperm from control mice. Most of these regions were within intergenic and CpG islands but not within coding genes.
When these first-generation males—who were fed regular diets—were bred with control female mice not exposed to malnutrition while in the womb, these germline hypomethylated regions were not transmitted to the second generation. However, some of these same regions in the brains and livers of second-generation male fetuses showed differential expression compared to controls.
The file is growing; we’ll see.
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