Year of birth significantly changes impact of obesity-associated gene variant

Anotehr possibility might be chemical exposures.

http://www.eurekalert.org/pub_releases/2014-12/mgh-yob122414.php

Public Release: 29-Dec-2014
Massachusetts General Hospital

Investigators working to unravel the impact of genetics versus environment on traits such as obesity may also need to consider a new factor: when individuals were born. In the current issue of PNAS Early Edition a multi-institutional research team reports finding that the impact of a variant in the FTO gene that previous research has linked to obesity risk largely depends on birth year, with no correlation between gene variant and obesity in study participants born in earlier years and a far stronger correlation than previously reported for those born in later years.

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"We know that environment plays a huge role in the expression of genes, and the fact that our effect can be seen even among siblings born during different years implies that global environmental factors such as trends in food products and workplace activity, not just those found within families, may impact genetic traits," says Rosenquist, an instructor in Psychiatry at Harvard Medical School. "Our results underscore the importance of interpreting any genetic studies with a grain of salt and leave open the possibility that new genetic risk factors may be seen in the future due to different genetically-driven responses to our ever-changing environment."

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