DNA is considered the Holy Grail of genetics and evolutionary biology alike. Without DNA as the carrier of hereditary information, complex life on this planet is unthinkable.
What is DNA?
DNA is the abbreviation for “deoxyribonucleic acid“. For biochemists, this designation already says the most important things about its structure, but in normal cases it requires a few explanatory words. DNA is a complex molecule made up of two almost identical individual strands, and it is precisely this “almost” that hides the origin of genetic diversity. Each strand consists of a stable deoxyribose-phosphoric acid chain to which various organic bases are attached. Both strands are intertwined to form a double helix and thus form DNA. But that’s not all: extremely long DNA threads organize themselves into a large overall complex, the chromosomes, of which humans have 23 pairs in the nuclei of all body cells. These chromosomes contain all the hereditary information (genes) encoded in the DNA that makes each living being an individual.
Medical and health functions, roles, and meanings.
Each cell fulfills a specific purpose in the organism. What this purpose consists of, ribosomes can read from the DNA located in the cell nucleus. But how exactly does this fundamental cellular building block work? The key to understanding molecular DNA genetics lies in the conjugated base pairs adenine, thymine, guanine and cytosine. These are linked to DNA in a precisely defined sequence, much like an encrypted code. The DNA is converted into similar mRNA so that it can be run through by a ribosome. This picks up the code, which provides the ribosome with the sequence of amino acids. The ribosome produces the corresponding amino acids and forms characteristic proteins from them, which ultimately enable cell functionality. In this way, abstract DNA becomes tangible cellular building blocks. Each human cell can only survive for a limited time, so that cells and with them the DNA must reproduce. This happens in a similar way to bacteria by means of cell division. The DNA is split into its individual strands by helicase. After the separation, this enzyme uses both strands as separate matrices and forms the missing counter strand anew in each case, so that two identical DNA molecule chains are created. The following two extrapolations show how unimaginably huge the DNA information density is: A single gram of DNA has a data volume of 700 terabytes. To replicate all the people on earth, a teaspoon must be filled with just 0.3% DNA. And if you wanted to string together the entire DNA of a single human being, you would have to travel to the sun and back 500 times.
Diseases, ailments and disorders
DNA is exposed to a wide variety of disruptive influences over the years. These range from the ingestion of cell-altering substances such as burnt meat or tobacco consumption to extreme heat and UV radiation. Last but not least, DNA changes can also occur as a result of faulty metabolic processes. To ensure that the valuable information is nevertheless preserved throughout a cell’s life, various biochemical repair and sorting mechanisms exist. But every now and then, especially with increasing age, cell regeneration can fail and DNA can be altered. Individual bases may be swapped or removed, entire regions unreadable, the strand bisected, in short, the genetic code is now incorrect. If the cell is still able to divide, a defective cell can, over time, lead to a whole collection of diseased cells. If such DNA mutations are still expressly desired in the sense of evolutionary theory, they usually mean a diagnosis of cancer in all its facets for the specific patient. However, sickle cell anemia, albinism, cystic fibrosis or hemophilia can also result from DNA mutations in addition to heredity. A particularly sophisticated form of life that makes use of foreign DNA is represented by certain types of viruses. They cannot reproduce on their own and infiltrate foreign cells for this purpose. In these cells, they replace the DNA with their own and are thus reproduced by the host cell in pathogenic form. Dangerous viral diseases and even death can be the result.
