Lead Exposure in Mothers Can Affect Future Generations
The study of variation in traits that are caused by environmental factors is known as epigenetics and is unraveling many mysterious of our genome. These environmental factors can cause genes to switch on or off, thus affecting how the cells read these genes and subsequently, changes in the DNA sequence. The expression of certain genes can have disastrous effects on the body, for example, by preventing formation of enzymes involved in detoxification of the body.
A team of researchers at Wayne State University have discovered that mothers with high levels of lead in their blood not only affect fetal cells of their unborn children, but also their grandchildren. This study that was led by Douglas Ruden, Ph.D., professor in the Department of Obstetrics & Gynecology and the Institute of Environmental Health Sciences, director of epigenomics, and program leader in the Center for Urban Responses to Environmental Stressors, revealed that lead exposure can cause specific changes in DNA methylation, which can be detected in dried blood spots beyond one generation.
“Our results suggest that lead exposure during pregnancy affects the DNA methylation status of the fetal germ cells, which leads to altered DNA methylation in grandchildren’s neonatal dried blood spots,” said Ruden. “This is the first demonstration that an environmental exposure in pregnant mothers can have an epigenetic effect on the DNA methylation pattern in the grandchildren.”
Epigenetic effects of environmental exposures beyond one generation have not yet been demonstrated in humans prior to this study. What this means is that maternal exposure to lead (and heavy metals and any other risk factors) may cause permanent changes in the DNA which will be passed on through the DNA. Even without high levels of lead, future generations will already be carrying these genes in their body. Some of these changes may be harmful to health. Amalgam (silver fillings) contain mercury.
Mercury is another heavy metal and it has been shown to cause DNA methylation in cells. Where do we go from here?