Your lifestyle is an on/off switch for your genes
We know that our lifestyle affects our health. We've heard it a million times before. Some of us take it more seriously than others. What we haven't really heard much of is how this relates to the inherited illnesses that people are at-risk of getting. Interestingly, again, it is actually lifestyle that significantly affects our chance of actually getting the illness that we're at risk of. For instance, someone born with a BRCA mutation, isn't necessarily going to get breast cancer. They are more at risk of getting breast cancer than someone who is born without the mutation, but they may or may not get it. Lifestyle actually plays a major, major role in whether an 'at risk' individual will end up developing the disease. There's a biochemical basis to all this - it's called Epigenetics.
Epigenetics is a field of Genetics that has had an overwhelming amount of research in the last 20 years. The thing that is extremely exciting about this, is that our genetic 'blueprint' is controllable. It isn't as set as we thought it is.
You may have read in previous blogs here about what happens when genes are switched on: the DNA that contains the genes is opened and unravelled, is 'read' by cellular machinery, a complementary copy of the gene in the form of mRNA is made, and then mRNA is processed through a ribosome factory, which makes the relevant protein which was originally coded on the DNA. It's really quite extraordinary, and a very elegantly designed process.
Epigenetics controls the switching on and off of genes. It does this quite simply: it tags them with what is known in the chemistry world with a methyl group. Genes that are tagged with methyl groups are switched off. The thinking is that this methyl group allows a group of proteins to bind to the 'on' switch of a gene, making it no longer available for activation.
The super interesting bit is that in a very famous Epigenetics/twin study, researchers found that the more different the twins were - especially if they had grown up separately, or had had very different life histories, the more epigenetically different they were. It was concluded that Epigenetics was the biochemical basis for the differences seen in identical twins. What this means, is that the way we live our lives - our diets, exercise habits, environment and general lifestyle physically affects the way our genes are controlled.
In cancer, the two main groups of genes that are mutated are called Oncogenes and Tumour Suppressor genes. Oncogenes act to induce cell proliferation whereas Tumour Suppressor genes act to inhibit cell proliferation. Interestingly, in cancer, Tumour Suppressor genes have been found to be epigenetically modified to be 'hypermethylated.' In other words, they have been switched off and are not functioning to stop uncontrolled cell growth. The really interesting observation about this is that it has been Epigenetics, caused by diet/lifestyle, that have switched off the gene.
More about Oncogenes and Tumour Suppressor genes in the next blog