While our bodies age, scientists believe our DNA remains constant. But new research, however, reveals subtle chemical changes occur to our DNA as we age, even though its sequence remains constant. Researchers claim it could explain why the risks of developing diseases increase as we get older.
DNA is made up of four basic chemical building blocks called adenine, thymine, guanine and cytosine. It is the sequences of those chemicals in a strand of DNA that determines what function a gene has, and one of the ways the resulting genes are controlled is a process called methylation.
This process means that a methyl group — one carbon atom and three hydrogen atom — bonds to part of the DNA and subtly changes its function. But the latest research shows our DNA’s susceptibility to methylation changes as we grow older.
A team of researchers from the Bellvitge Biomedical Research Institute in Barcelona, Spain, extracted DNA from white blood cells of 20 newborn babies and 20 people aged between 89 and 100 years, and then compared their respective degrees of methylation.
In a newborn baby, 73% of cytosine nucleotides were methylated, while in centenarians that figure rose to 80.5%. It’s not clear why it happens, according to researchers, but they speculate it could be due to extremely subtle age-related changes to the DNA.