Have you ever wondered why/how people change so much as they grow older in terms of appearance and disease risk? Well, a recent study compared the methylation patterns in newborns to those of 89-100 year olds to answer some of those questions. Methylation is one mechanism through which genes are turned on or off. I’ll take another step back for those of you not in science. DNA is a sequence of nucelotides (specific chemical components), and the sequence of a gene determines which proteins are made in the cells. Since most proteins don’t need to be made all of the time, it’s important for there to be ways to turn the genes on or off. One mechanism for regulating gene expression (a gene is expressed when it’s turned on) is methylation. Methylation is simply adding a methyl group (made up of one carbon and 3 hydrogen atoms) to one of the nucleotides in the DNA sequence, changing whether or not the gene is expressed (it usually, but not always, turns off the gene in question).
Anyway, the study showed that older people generally lack methylations groups, allowing certain genes to be turned on, when in newborns those genes are turned off. Many of the genes identified in the study that switched to being on have previously been associated with diseases and cancers. So it seems that as you age your DNA expression changes, and some genes that are associated with disease are more likely to be expressed. Maybe this information can help us find the fountain of youth!