Tuesday, April 19, 2011

You are what your mother eats

A story on the BBC site this week reports research that has found DNA modification in infants that affects their prospects for increased body weight.
A mother's diet during pregnancy can alter the DNA of her child and increase the risk of obesity, according to researchers.
The study, to be published in the journal Diabetes, showed eating a lot of carbohydrate changed bits of DNA.
It then showed children with these changes were fatter.
This is not new, but is another of the current themes in genetics, to look for environmental effects that can be inherited.

Epigenetic changes alter DNA's chemical configuration by modifying the nucleotides (the A's, C's, T's, and G's), rather than by mutating--changing--them.  Modification of the DNA in this way can change the chemical machinery in cells that affects which genes the cell does or doesn't use.  Modifications like this are inherited when the cell divides, until re-set by later mechanisms.

Epigenetic changes in metabolism can affect how much weight a person gains.  If the changes are 'remembered' by the individual's cells and also imposed on that person's gametes or offspring, they can be inherited and can appear genetic.  But they are environmental (unless the person's DNA sequence makes it more vulnerable than someone else's to undergoing this epigenetic change in a particular environment).

Although yet another must-do approach, or fad, it is not yet clear how important epigenetic changes will prove to be.  If they are inherited in the sense that they reflect the infant's experiences in gestation, they may not necessarily be transmitted to the next generation.  But they may be important in trying to understand traits like obesity, because one looks typically for the person's life experience: exercise, diet, and the like, when examining the person's mother's experiences during or even before her pregnancy might also be informative.

Of course, overeating is overeating, and it can make you gain weight regardless of the origin of the gene expression patterns that such exposures induce.


Holly Dunsworth said...

What else would you or could you be? :)

EllenQ said...

You could be what your grandmother eats. I saw a talk at the AAPAs last week by Chris Kuzawa that showed correlations of birth weight with grandmother's caloric consumption during adulthood (and pregnancy) and mother's caloric consumption during infancy. Interestingly, there was no relationship detected between maternal caloric consumption during pregnancy and birth weight.

Holly Dunsworth said...

He does really cool stuff. (I was being cute about molecules.)