Diet during pregnancy affects development of offspring
By Ruth SoRelle, M.P.H.
If the saying "you are what you eat" rings true, then the scientific corollary may be that what your pregnant mother ate plays a permanent role in your physical make-up as well.
Studies in mice by Robert Waterland, Ph.D., assistant professor of pediatrics at Baylor College of Medicine and the U.S.D.A/A.R.S Children's Nutrition Research Center at BCM and Texas Children's Hospital, show that small changes in the diets of pregnant mice can have profound effects on the development of their offspring, dramatically changing the appearance of genetically identical young mice. His most recent study in the area appears in the journal Genesis.
Biological mechanism
"There are a lot of published studies showing that nutrition during the prenatal and early postnatal period of life can have an effect on chronic disease susceptibility," said Waterland. "However, little is known about the exact biological mechanism by which that happens."
Identifying these biological factors is the thrust of Waterland's work. In his most recent study, Waterland and colleagues at BCM and Duke University Medical Center in Durham, N.C., studied the effect of a change in maternal diet on mice known for a genetic mutation that caused their tails to kink.
In this instance, a piece of DNA called a retrotransposon inserted itself into a portion of the axin gene. These animals, known as "axin-fused" mice, are often born with kinky tails.
However, when pregnant axin-fused mice were fed a diet with extra folic acid, vitamin B12, betaine, and choline, their offspring were about half as likely to have tail kinks than were the offspring of mother mice fed a normal diet. The scientists found that this occurred because the diet led to increased DNA methylation of the axin gene (literally adding a component called a methyl group to DNA), chemically "handcuffing" the gene and preventing it from producing the protein that led to tail kinking.
Earlier, they found a similar process involved in determining coat color in a strain of mice called viable yellow agouti or Avy. However, in those mice, the effect of the diet was seen much earlier in development than that seen in the axin-fused mice.
Diet could be used as strategy
The two studies involved bits of DNA known as metastable epialleles, where DNA methylation varies dramatically among different individuals. In both cases, the viable yellow agouti and the axin-fused mice, DNA methylation in these portions of the genome was affected by the maternal diet, suggesting a strategy for identifying similar spots in the human genome that are affected by maternal diet.
Others who participated in this research include Dana C. Dolinoy of Duke University Medical Center and Juan-Ru Lin, Charlotte A. Smith, Xin Shi and Kajal G. Tahiliani of Baylor College of Medicine.
Funding for this research came from the National Institutes of Health, the U.S. Department of Agriculture and the March of Dimes Birth Defects Foundation.
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