Have we stopped evolving? If you’re a fan of the Marvel Comics mutant series, in that universe, a few people carry the brand new, mutant X gene that allows them superhuman powers. While this morning’s study hasn’t unearthed any mutants with X-ray vision or super strength, it is fascinating because it shows that we are still evolving.
Your chromosomes are the clumps of DNA molecules inside each cell, and it’s the chromosomes that house our genetic information. In fact, they do look like little “X”s, so it’s no surprise where Stan Lee, the recent head of Marvel Comics, got his mutant series title, X-Men. Our genes are the instruction manual for how our cells work and how new cells are built. Our DNA structure is not unchangeable; in fact, our base code is constantly being modified, changed, and edited, and there are a variety of internal and external, natural and forced influences that make this happen.
Epigenetics is the study of how our genes can be modified by the environment. One way your genes get altered is by the body placing a marker on the area. This is called DNA methylation, and this marker is one of the things that regulate gene expression, which is how proteins are made. Meaning, your genes can make one specific protein that you need, or another, just by using one part (expressing) of the gene or another that provides the code for how that protein is made.
When DNA methylation is negatively influenced, such as by a poor diet or smoking, this can damage the cell, leading to cancers and other diseases. DNA methylation is such a powerful process that if it damages reproductive cells, and this can be passed through many generations. It may also be positively influenced by things such as a healthy diet and stress management. One study found that DNA methylation in genes that relate to cancer and the metabolism of estrogen was positively influenced in women who consume certain types of tea (e.g., green and black tea).
Our genes can also become damaged, causing problems in our genetic instruction manual and, therefore, abnormalities in the cell. For example, genetic defects can occur when cells are damaged by chemicals, which disrupts our genetic instructions. One cause of these genetic abnormalities could be wear debris (shedding of particles from the prosthetic material) from artificial joint replacements. Genomic instability can also occur. This happens when gene mutations occur at a high frequency. Genomic instability is like trying to use an instruction manual that just keeps changing on you. Again, titanium wear particles from the metal commonly used for hip-replacement devices, can also cause genomic instability, and this genetic damage can be passed through generations. Abnormalities, such as instability, can lead to a variety of cancers and other diseases.
A new study has found that behind the scenes, deep in our DNA, our genes, influenced by either internal or external factors, may be going through a process of natural selection. What exactly is this “survival of the fittest” process getting rid of? Damaging genetic mutations, the study suggests, such as those responsible for Alzheimer’s and the susceptibility to heavy smoking. In its wake, natural selection is leaving each newer generation with stronger, healthier genes with a greater chance of longer survival.
The new study, a cohort of over 200,000 subjects, examined whether certain genetic variations or mutations influenced the length of survival. Researchers found two: The Alzheimer’s-associated gene, ApoE4, was less frequent in women older than 70. Another telling finding—the gene linked to heavy smoking in men, CHRNA3, dropped in frequency in middle age.
The study also found many other interesting trait associations. For example, the later onset of puberty was linked to longer lifespans in both men and women who become parents. Women who have their first child at a later age were found to have longer lifespans. Genetic mutations were also found to affect lifespans of those with heart disease and asthma as well as cholesterol levels and obesity.
The upshot? So maybe we are all mutants? Our genes are evolving to protect us against things in our environment that are trying to hurt or kill us. Stan Lee would be proud…
About the Author
Christopher J. Centeno, M.D. is an international expert and specialist in regenerative medicine and the clinical use of mesenchymal stem cells in orthopedics. He is board certified in physical medicine as well as rehabilitation and in pain management through The American Board of Physical Medicine and Rehabilitation.…