Scientists have uncovered the first clear genetic evidence linking low birthweight and maternal malnutrition and subsequent ill-health. Writing in this week's PNAS Leiden University researchers Bastiaan Heijmans and his colleagues describe how they have analysed DNA samples from babies conceived during the 1944-1945 Dutch war famine. This happened at the end of the Second World war as the occupying German forces blockaded food supplies to parts of the Netherlands. Consequently the population starved and many existed on fewer than 500 calories per day, less than 25% of what consitutes a healthy diet. Although the country was subsequently liberated and the population returned to good health, an interesting pattern emerged amongst the children conceived during the famine. These individuals have shown a tendency towards increased weight gain, diabetes and heart disease compared with their brothers and sisters who were born outside of the famine period. To find out why Heijmans and his colleagues focused their attention on a gene called IGF2, which is a growth factor, the genetic workings of which are very well understood. Specifically the team studied a pattern of chemical markers that can be attached to DNA to regulate gene activity rather like a dimmer switch. This is known as epigenetics and adds another dimension to the control of genes. The team were very surprised to find that the IGF2 genes of the famine babies had 5% fewer methyl groups attached to them compared with healthy controls and also their own siblings born at different times. "What is amazing is that we are still seeing this chemical effect more than 60 years - a whole lifetime - since these people were exposed to this insult," says Heijmans. "This shows that there can be lifelong consequences for a child due to the environment in which its mother lives." In other words, although famines are fortunately quite rare today, other maternal insults, like smoking, alcohol, drug use and other dietary deficiencies could have an irreversible epi-genetic effect on a developing baby...
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