A mother's diet before conception can permanently alter the DNA of the offspring that may affect his/her development, a significant study shows. "Our results represent the first demonstration in humans that a mother's nutritional well-being at the time of conception can change how her child's genes will be interpreted, with a life-long impact," explained Branwen Hennig from MRC International Nutrition Group and London School of Hygiene and Tropical Medicine. To prove their point, the researchers utilized a unique 'experiment of nature' in rural Gambia. Through a selection process involving over 2,000 women, the researchers enrolled pregnant women who conceived at the peak of the rainy season (84 women) and the peak of the dry season (83 women). After a thorough analysis, they found that a mother's diet before conception had a significant effect on the properties of her child's DNA. The researchers found that infants from rainy season conceptions had consistently higher rates of methyl groups present in all six genes they studied.These were linked to various nutrient levels in the mother's blood. Strong associations were found with two compounds in particular (homocysteine and cysteine) and the mothers' body mass index (BMI) had an additional influence. "While a child's genes are inherited directly from their parents, how these genes are expressed is controlled through 'epigenetic' modifications to the DNA," the study said. DNA methylation is one of several epigenetic mechanisms that cells use to control gene expression. "It shows that the methylation machinery can be disrupted by nutrient deficiencies and that this can lead to disease. Our ultimate goal is to define an optimal diet for mothers-to-be that would prevent defects in the methylation process," stressed professor Andrew Prentice from London School of Hygiene & Tropical Medicine. According to Rob Waterland from Baylor College of Medicine in Houston, "we selected these gene regions because our earlier studies in mice had shown that establishment of DNA methylation at metastable epialleles is particularly sensitive to maternal nutrition in early pregnancy". The study appeared in the journal Nature Communications.