In a new report published in the journal Genome Biology, researchers combed the genome to find regions that are particularly vulnerable to outside influences, such as diet, nutrition and environmental exposures, to determine how these factors might affect a developing fetus.
While the genes encoded in every person’s genome determines his characteristics, a second layer of genetic activity, called epigenetics, controls which genes are turned on and which are shut off, at different times in different cells. It’s epigenetics that is responsible for ensuring that a hair cell becomes a hair cell and not a liver cell, and so on. For the most part, these instructions are set during early development in the embryo.
But, as Robert Waterland, associate professor of pediatrics and molecular and human genetics at Baylor College of Medicine and his team found, there are discrete places in the genome where epigenetic changes are more vulnerable to external influences like diet. They conducted a genome-wide survey to find these regions, and then tried to match them up with easily measurable factors such as nutrition or mothers’ diets.
They did this in a population of women in Gambia, where changing seasonal availability of food allowed them to compare women who conceived during times when food was scarce, to those who conceived when crops were more abundant. Indeed, they honed in on a specific variant in a gene that is involved in suppressing tumors. When this gene is epigenetically activated, it leads to protection against cancer, but may lead to lower immune system function and this activation is influenced by a mother’s nutrition. Lower levels of vitamin B2 may contribute to inceeased cancer suppressing activity, and that may establish an lower risk for cancer among children while they are still in the womb.
“Very different maternal nutritional status nudges the distribution of the epigenetic state in one direction or the other,” says Waterland. “In the next phase of research we want to directly test whether individual epigenetic variations in fact leads to changes in the risk of diseases included cancer and immune-related conditions.”
What’s encouraging about the findings is the fact that in addition to the gene they studied in detail, the scientists also found 108 other genes that might be influenced by factors such as diet. Other such external contributors that Waterland is hoping to investigate are things such as mother’s obesity and the effect of IVF, in addition to environmental contaminants such as pollution or cigarette smoke.