MOLECULAR GENETICS
The Molecular Genetics Department performs DNA tests for inherited or acquired genetic diseases, certain infectious diseases, and predispositions to specific pathological conditions, using modern technologies such as PCR, PCR-RFLP, QF-PCR, quantitative PCR, MLPA, and MS-MLPA.
What is DNA?
DNA (deoxyribonucleic acid) contains the genetic code that instructs our body how to grow and function. It is a double-helical molecule organized into microscopic structures called chromosomes, located in the nucleus of all our cells. Each DNA molecule is composed of four nitrogenous bases—A (adenine), T (thymine), G (guanine), and C (cytosine)—arranged in different combinations. The order and sequence of these bases determine the structure and function of the organism.
An important property of DNA is its ability to self-replicate, producing identical copies; this is critical because when a cell divides, each new cell has an exact copy of the DNA present in the original cell. Human DNA is 99.9% identical among individuals. The uniqueness of each person comes from the 0.1% of DNA that differs.
What is a gene?
A gene is the basic structural and functional unit of heredity. Genes are made up of DNA sequences and are located on chromosomes. Each chromosome contains thousands of genes, composed of several thousand base pairs.
Genes contain instructions for synthesizing proteins and regulating cellular differentiation. The genome (the totality of genes) is responsible for the normal development of each individual. Every human being has two copies of each gene, one inherited from each parent.
What is a mutation?
When a cell divides, DNA replicates, and as a result of the division two identical cells are formed, each with a complete set of genetic information. Sometimes, during replication, errors can occur, resulting in changes in the coding structure. These changes are called mutations. Mutations can be inherited from a parent and passed on from generation to generation, or they can be acquired during life, in which case they are not inherited.
Mutations that occur in an egg cell, sperm cell, or immediately after fertilization are called de novo mutations. Most mutations have no impact on health or development because, although they alter the structure of a gene, they do not affect its function. When a mutation changes the expression of a gene that contains the information for producing a protein—either causing the protein to function abnormally or to be completely absent—normal development may be disrupted or medical conditions may arise.
