Astronomy

DNA, the code of life

DNA, the code of life

Deoxyribonucleic acid or DNA is the molecule that contains life's information. His discovery will go down in history as one of the great advances of the s. XX.

Already in 1869 Friedrich Mieschen managed to isolate it from white blood cells, but never knew of its importance. In 1953 James Watson and Francis Crick discovered the structure and behavior of DNA, which earned them the name of medicine in 1962.

DNA is responsible for the resemblance between parents and children, and that there is a common mold for each species. It contains all the genetic information, the design instructions of each and every one of us. And the rest of living beings, from the simplest bacteria to the most complex organism. In the DNA there are tens of thousands of genes. They are responsible for manufacturing the proteins necessary for the development of different vital functions.

Most of the DNA is in the nucleus of the cells. Each cell in our body stores a copy of this information. Each DNA molecule is made up of two chains of nucleotides that cross each other in the form of a double helix. It is that image so characteristic that it comes to mind when talking about DNA.

Nucleotides are actually smaller molecules, and there are four types: adenine (A), thymine (T), cytosine (C) and guanine (G). The four combine to form the genetic code, just as the letters combine to form words: ATTC TCGA ...

All this information is scattered throughout the nucleus. But, when the cell is going to divide, it is arranged in small packages in the form of sticks: the chromosomes. In human cells there are 23 pairs of chromosomes in total. The information in them is very compacted, because they contain the thousands of genes. When the cell divides, the information is transmitted and the DNA creates a copy of itself.

The new copy should be identical. But is not. Typically, failures are made in the process. So, we talk about mutations. We all have some mutations in our genes. Most lack importance. Sometimes, however, they can cause very serious diseases or consequences. Mutations are not always negative. Sometimes they provide an advantage over other individuals and contribute to the evolution of the species. This has happened in the history of evolution, although it is not usual.

There is also DNA outside the cell nucleus. It is the mitochondrial DNA, which remains even in very old remains of living beings. Unlike the nucleus DNA, the mitochondrial is only inherited from the mother. Thanks to him, it is known that almost all of us descend from a small group of mothers who survived an ice age during the Paleolithic. DNA is very useful in the study of the great human migrations of history. The study of fossil DNA provides data that is not obtained in any other way.

Its usefulness is evident in fields such as medicine, crime resolution, identification of missing persons, determining paternity, etc. All the information of any living being is written in their DNA. Determine our physical traits, character, aptitudes, family ties, predisposition to suffer from diseases, or to adopt some behaviors or others ...

But let's not be pessimistic. DNA does not program our life and our destiny. Many other factors are involved such as the environment in which we are born, the education received, food, habits of life, circumstances ... The DNA deals the cards, but does not decide the game.

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