Anatomy-Lexicon

Epigenetics

definition

Epigenetics is a broad and extensive biological field that deals with genetic functions that go beyond the pure sequence of bases in DNA.
The genome consists primarily of DNA strands that are formed from differently arranged base pairs. In every person there are differences in the order of the base pairs, which ultimately determine the individuality of each person.
But even with the same genome, epigenetic factors can lead to the gene sequences being implemented differently and leading to further differences.
Nowadays, these epigenetic characteristics of a person can only be partially examined in the genome.

Even with apparently intact genetic material, these epigenetics can result in diseases through subsequent modification of the genetic material.

How does epigenetics work?

The human genome, which is located in the chromosomes, consists of numerous base pairs that code for the genetic material.
The base pairs define a code according to which the body converts the genetic material.
Genetic diseases arise from the fact that mutations or shifts occur on the genes at individual bases, whereby the code is incorrect and a wrong gene is produced.
A typical example of such a disease is cystic fibrosis. Different mutations and malformations lead to a defect in the “CFTR gene”, which codes for a chloride channel in various organs.

In the case of epigenetic changes, there is no such clear change in the gene.
To convert the gene into a corresponding product that works and is active in the body, numerous other processes come into play:

The DNA is packaged and must first be loosened so that the gene sequences to be produced are exposed. In epigenetics, processes take place on the DNA bases themselves or the packaging of the DNA strands, which changes the production method of individual gene segments. This allows individual gene areas to be highlighted while other sections are shut down.

The effects of epigenetic changes on the genome can be considerable. This means that important gene sequences can be completely shut down, while other genes are overproduced.
This can result in diseases and different physical characteristics in different ways.
In the course of life, epigenetics changes due to age and under the influence of hormones and environmental factors.

For this reason, it is assumed that epigenetics has a decisive influence on the development of cardiovascular diseases and the process of aging.
Schizophrenia, Alzheimer's disease, cancer, diabetes and psychiatric illnesses may also arise in connection with epigenetic changes.
A lot of research is still going on in this field so that various diseases can possibly be explained and better treated in the future.

Examples of epigenetics

Epigenetic examples can be observed in every person in old age. Many disease origins today are attributed to epigenetic changes, among other things.
A typical example of visible epigenetics is the so-called "X-inactivation".
An X chromosome is completely shut down by epigenetic processes. This especially affects women who have two X chromosomes.One X chromosome remains active, which is why there are no noticeable clinical symptoms.
This can lead to genetic so-called "recessive" diseases breaking out on the still activated X chromosome, which otherwise would not have occurred because they could have been compensated for by the second X chromosome.

Another example of epigenetics is what is known as “genomic imprinting”.
The child's genes have a parental genomic imprint, which means that only genes from one parent are active. This can also lead to rare diseases such as Angelman syndrome, Prader-Willi syndrome or even tumor diseases such as Wilms' tumor.
The exact effects of genomic imprinting on these diseases are still largely unexplored.

What role does epigenetics play in cancer?

The connections between epigenetics and the development of cancer are intensively researched. Most cancers result from the uninhibited replication of cells, which then turn into tumor cells.
Genetic modifications or epigenetic factors can be behind this.
These can highlight individual gene sequences and lead to tumor growth.

Both childhood and adult tumors can be due to epigenetic changes.
These diseases can still be researched particularly well in children because they have very similar epigenetics. In the course of life, epigenetics changes due to age and various environmental factors.
This opens up new possibilities for tumor development.

These epigenetic malregulations of genes can, however, also be used to your own advantage in cancer treatment. In principle, it is possible to change the epigenetics of an activated gene in such a way that cancer is eliminated directly.

There are still major gaps in research both in the development of cancer and in the treatment of cancer through epigenetic mechanisms.
So far it is not yet possible to use these methods therapeutically.

What role does epigenetics play in depression?

Epigenetics plays an important role, especially in the development of psychiatric diseases.
By activating and inactivating certain gene sequences, diseases such as depression and schizophrenia can develop.

Age and environmental factors that lead to changed epigenetic processes are probably also responsible for this. Mental illnesses interact with human epigenetics.
For example, it is known that psychological stress leads to epigenetic changes that lead to cell aging.

Severe psychological stress in childhood also has a significant influence on epigenetics, which can lead to psychiatric complications at a later time.

Read more on the topic: Causes of depression

Epigenetics in twins

Research into epigenetics can be done very well, especially in identical twins.
Although these have the same genetic make-up, they can have significantly different external and internal characteristics in the course of their life.

These differences can be traced back to epigenetic changes caused by chance and environmental factors. Even if each twin has the same genetic make-up, only a few gene sequences are activated, for which the individually different epigenetics are responsible.

At a young age, epigenetics hardly differ.
With increasing age and different environmental influences, the differences become more obvious.
However, there is still an epigenetic imprint.
This means that the likelihood of similar epigenetics with the development of epigenetically caused diseases in twins remains high.

More information about twins: Twin Pregnancy - What You Should Know!

What influence do environmental influences have on epigenetics?

According to the current state of research, epigenetics is significantly influenced by advanced age, coincidences and environmental factors.
The environmental factors can be of a psychological and physical nature.

Well-known negative environmental factors that cause a negative change in epigenetics are childhood trauma, stress, psychological distress or depression.
An unhealthy diet or harmful chemicals such as tobacco smoke or alcohol also have a negative influence on the epigenetics of the genetic makeup.

At an advanced age, various environmental influences through epigenetic changes can result in diseases of the psyche, the cardiovascular system, but also numerous other organs.
However, the exact relationships and modes of action in the genome have not yet been researched.