WHAT MAKES ME ‘ME’?
The DNA sequence is our destiny – have you ever wondered about this statement? Is the development of genetics the final step in finally knowing who we really are? With the genetic revolution of the 20th century and the rapid development of technology, the world hoped to find answers to these questions. This excitement resulted in many discoveries, including why we have blue eyes, where albinism comes from, and whether each of us can be born with cystic fibrosis. The icing on the cake was a 10-year learning project about the human genome – more than 3 billion bricks (so-called principle pairs) defining man as a species, but also as an individual. After a while, however, the euphoria subsided and scientists began to consider the possibility of discovering genes and linking them to characteristics, Homo sapiens . How do we explain that identical twins (with the same genome) can differ phenotypically and not develop the same diseases? Or why the cells in our body are so diverse even though they originate from the same zygote that originated with fertilization? A relatively new subfield of biology – epigenetics – comes to the rescue.
THE PHENOMENA OF EPIGENETICS
Epigenetics deals with changes in gene expression not resulting directly from DNA sequence mutations, which lead to the formation of both intra-generationally and inter-generationally inherited traits. Let’s imagine a beehive. Within a hive, all the bees are genetically identical. So how come worker bees, soldier bees, and queen bees are born from the same genome? The answer lies in the diet: larvae that receive pollen develop into worker bees and those that receive royal jelly become queens. How is this possible?
Here lies the need to explain what makes up the epigenetic phenomenon. The most fascinating mechanism of epigenetics is DNA methylation, that is, attaching a small “marker” directly to the nucleotides (components – A, T, C and G) within the DNA. Histone modifications are another very important mechanism in epigenetics. But what are histones? These are proteins that help maintain the proper spatial structure of our DNA. Adding a “marker” to the histone will locally loosen the structure of the DNA and thus increase the possibility of using this part of the molecule.
CAN WE INHERIT THE EXPERIENCE OF OUR PARENTS?
After 2007, the breakthrough in the field of epigenetics surprised the world of biology. Mice with a gene called Agouti , responsible for yellow color and diabetes, causing obesity and rapid death, were fed food as a source of methyl groups (“markers”) during the experiment. To their great surprise, the offspring born were brown, thin, did not suffer from diabetes, and lived for a long time. The cutia gene still existed in their cells, but was silenced by the aforementioned methylation. Moreover, the blockage appeared even in the next generation of mice. A conclusion was reached – we are not only what our parents ate, but also what our grandparents ate. Following this trail, it turns out that in addition to food, it is of great importance for the development of future generations if we smoke, move often, or even think positively. All these actions influence changes in our epigenome. Today we know that DNA is not our destiny, although it plays a huge role in shaping it. Genetics carries guns, but it is epigenetics that pulls the trigger.
EPIGENETICS AND DIABETES
Diabetes is a chronic disease caused by hereditary and/or acquired deficiency of insulin produced by the pancreas, which leads to increased blood glucose levels (hyperglycemia) and thus many complications. Chronic hyperglycemia is associated with damage, dysfunction, and failure of various organs, especially eyes, kidneys, nerves, heart, and blood vessels. Diabetes research is the apple of the eye for many scientists around the world. Currently, more and more attention is being paid to evaluating the influence of non-genetic factors on the development of this disease of civilization. To demonstrate the relationship between environmental and genetic factors, studies have been conducted on newborns with low birth weight. It was then hypothesized that malnutrition in the mother may be the cause of the later development of diabetes in children. The results of these studies confirmed that disturbances in the intrauterine environment contribute to the formation of epigenetic modifications and affect the development of the fetus. More importantly, they can lead to many diseases – including diabetes – in the future (its further development), even many years later.
Every day new reports emerge about the role of epigenetic factors (especially diet and physical activity) in increasing the occurrence of diseases of civilization, such as the aforementioned diabetes and cancer or very common diseases of the vascular system. In addition to the above, there is an increasing trend in studies showing the impact of environmental pollution.
So far, scientists at the Foundation for Research and Scientific Development have been able to prove that the activity of individual genes varies depending on the method of treatment of diabetes mellitus. Therefore, Magdalena Gomółka is currently preparing a plan for further research aimed at assessing the influence of non-genetic factors and gene activity on the development and course of various types of diabetes.
Author of the article: Michał Wszoła MD, PhD
