It is the field that studies the structure and function of genes at the molecular level.
Genetics seems quite intimidating, but in its purest sense it is quite simple. The basis of the genetics is quite simple: DNA => RNA => A Protein.
DNA or deoxyribonucleic acid (DNA) is a long molecule that contains our unique genetic code. Almost all the cells in a person’s body have the same DNA.
Most DNA is found in the nucleus of the cell (where it is called nuclear DNA), but you can also find a small amount of DNA in the mitochondria (where it is called mitochondrial DNA or mitochondrial DNA).
The information in the DNA is stored as a code composed of four chemical bases: adenine (A), guanine (G), cytosine (C) and thymine (T).
Human DNA consists of approximately 3 billion of these bases, and more than 99 percent of those bases are the same in all people. The order or sequence of these bases determines the information available to build and maintain an organism.
The DNA bases
These are matched to each other, A with T and C with G, to form units called base pairs. Each base is also linked to a sugar molecule and a phosphate molecule. Together, a base, sugar and phosphate are called nucleotides.
The nucleotides are arranged in two long strands that form a spiral called a double helix.
The structure of the double helix is something like a ladder, with the base pairs forming the steps of the ladder and the sugar and phosphate molecules forming the vertical sides of the ladder.
Ribonucleic acid (RNA) is very similar to DNA, but differs in some important structural details: RNA nucleotides contain ribose sugars, while DNA contains deoxyribose.
The RNA predominantly uses uracil instead of thymine present in the DNA. RNA is transcribed (synthesized) from DNA by enzymes called RNA polymerases and then processed by other enzymes.
RNA serves as a template for the translation of genes into proteins, the transfer of amino acids to the ribosome to form proteins and also the translation of transcription into proteins.
The RNAs serve as the working set of blue prints for a gene. Each gene is read, and then the messenger RNAs are sent to the molecular factories (ribosomes) that build the proteins.
These factories read the plans and use the information to make the appropriate protein. When the cell no longer needs to produce more of that protein, the RNA planes are destroyed.
But because the master copy in the DNA remains intact, the cell can always go back to the DNA and make more RNA copies when it needs more encoded protein.
An example would be the ultraviolet light of the sun activating the genes in the cells of its skin to tan it. The gene is read and the RNA carries the message or plane to the ribosomes where melanin is made, the protein that tans the skin.
As we discussed, each gene is composed of a series of bases and those bases provide instructions for making a single protein. Any change in the sequence of bases can be considered a mutation.
Most mutations are “naturally occurring”. For example, when a cell divides, it makes a copy of its DNA, and sometimes the copy is not perfect. That small difference of the original DNA sequence is a mutation.
Mutations can also be caused by exposure to specific chemicals, metals, viruses and radiation. These have the potential to modify the DNA.
This is not necessarily unnatural, even in the most isolated and pristine environments, DNA breaks down. However, when the cell repairs the DNA, it may not do a perfect repair job. Then the cell would end up with DNA slightly different from the original DNA and, therefore, a mutation.
Some mutations have little or no effect on the protein, while others cause the protein not to work at all. Other mutations can create a new effect that did not exist before.
Many diseases are the result of mutations in certain genes. An example is the gene for sickle cell anemia. The mutation that causes sickle cell disease is a substitution of a single nucleotide (A to T) in the base number 17 of 438 A, T, C, and G.
By changing the amino acid at that point, the impact is that the red blood cells are no longer round, but are sickle-shaped and carry less oxygen.
Some of these changes occur in the cells of the body, such as skin cells as a result of exposure to the sun. Fortunately, these types of changes are not passed on to our children.
However, other types of errors can occur in the DNA of the cells that produce the eggs and sperm. These errors are called mutations in the germ line and can be passed from parents to children.
If a child inherits a germline mutation from their parents, every cell in their body will have this error in their DNA. Germline mutations are those that cause disease in families and are responsible for hereditary diseases.
Genetics and Arrhythmias
Sudden cardiac death (NDE) is a generalized health problem with several known hereditary causes. Inherited SCD usually occurs in healthy individuals who do not have other conventional cardiac risk factors.
It has been discovered that mutations in the genes responsible for creating the electrical activity of the heart are responsible for most arrhythmias, including short QT syndrome, long QT syndrome.
Brugada syndrome, Family branching block, Sudden infant death syndrome and Sudden and unexpected death.
Molecular Genetics and the Future of Medicine
As researchers discover the role of genes in the disease, there will be more genetic tests available to help doctors diagnose and determine the cause of the disease.
For example, heart disease can be caused by a mutation in certain genes or by environmental factors such as diet or exercise, to name a few.
Doctors can easily diagnose a person with heart disease once they have symptoms. However, doctors can not easily identify the cause of heart disease in each person.
Therefore, most patients receive the same treatment regardless of the underlying cause of the disease.
In the future, a panel of genetic tests for heart disease may reveal the specific genetic factors that are involved in a given person.
People with a specific mutation can receive treatment directed at that mutation, thus treating the cause of the disease, rather than just the symptoms.
Molecular Genetics Program
The ultimate goal of the MMRL Molecular Genetics Program is to identify the factors that are responsible for these diseases.
This knowledge will facilitate the development of gene-specific therapies and the healing of arrhythmias and will identify people at risk of sudden cardiac death.
With the incorporation of the Molecular Biology and Molecular Genetics programs, MMRL is now fully involved in basic and clinical research.
It is among the few institutions in the world with a consistent and concerted approach to unite basic and clinical science.
In order to design specific treatments and cures for the disease, laboratory research has the potential to affect us all.