Michael K Skinner, Ph.D.
Washington State University
NIEHS Grant R01ES012974
A mouse study, supported in part by the NIEHS, indicates that ancestral exposure to the insecticide dichlorodiphenyltrichloroethane (DDT) can promote obesity and associated disease in later generations. The findings imply that environmental exposures experienced several generations ago might influence today’s rates of obesity, although the degree of involvement is not known.
To examine potential transgenerational effects of DDT, the researchers transiently exposed pregnant female rats to DDT and then looked for obesity and obesity-related disease in the next three generations of offspring. The first generation offspring, which were directly exposed as fetuses, did not develop obesity but did show kidney disease, prostate disease, ovary disease, and tumor development as adults. In the third generation (great grand-offspring), more than 50 percent of males and females developed obesity. The transgenerational transmission of disease took place through both female and male germlines. The researchers found differential DNA methylation regions, which are epigenetic changes in sperm from the third generation. Epigenetic changes affect gene expression without changing the genetic code. Genes associated with the identified differential DNA methylation regions were previously shown to be associated with obesity.
DDT was developed as a pesticide in the 1940s and was commonly used in the United States until banned in 1972. It is very persistent in the environment and still used to control malaria in other parts of the world. The researchers say that the long-term health and economic effects of DDT exposure on future generations should be considered in areas where DDT is used.
Citation: Skinner MK, Manikkam M, Tracey R, Guerrero-Bosagna C, Haque M, Nilsson EE. 2013. Ancestral dichlorodiphenyltrichloroethane (DDT) exposure promotes epigenetic transgenerational inheritance of obesity. BMC Med 11:228.