Genetic changes may lead to heart disease and can be influenced by our diet and environment, a new study has suggested.
A University of Cambridge study, which set out to investigate DNA methylation in the human heart and the “missing link” between our lifestyle and our health, has now mapped the link in detail across the entire human genome.
“By going wider and scanning the genome in greater detail this time – we now have a clear picture of the “fingerprint” of the missing link, where and how epigenetics in heart failure may be changed and the parts of the genome where diet or environment or other external factors may affect outcomes,” Roger Foo, the lead researcher, said.
The researchers compared data from a small number of people with end-stage cardiomyopathy who were undergoing heart transplantation, and the healthy hearts of age-matched victims of road traffic accidents.
DNA methylation leaves indicators, or “marks”, on the genome and there is evidence that these “marks” are strongly influenced by external factors such as the environment and diet.
The researchers have found that this process is different in diseased and normal hearts, and linking all these things together suggest this may be the “missing link” between environmental factors and heart failure.
The DNA that makes up our genes is made up of four “bases” or nucleotides – cytosine, guanine, adenine and thymie, often abbreviated to C, G, A and T. DNA methylation is the addition of a methyl group (CH3) to cytosine.
When added to cytosine, the methyl group looks different and is recognised differently by proteins, altering how the gene is expressed i.e. turned on or off.
DNA methylation is a crucial part of normal development, allowing different cells to become different tissues despite having the same genes. As well as happening during development, DNA methylation continues throughout our lives in a response to environmental and dietary changes that can lead to disease.
As a result of the study, Foo likens DNA methylation to a fifth nucleotide:
“We often think of DNA as being composed of four nucleotides. Now, we are beginning to think there is a fifth – the methylated C,” Foo added.