Even though the theory proposed by Charles Darwin was very accurate and visionary, he did not have the basis of genetics. Even Gregor Mendell, when defining the mathematical laws of genetics, did not have enough information about what was happening at the gene level, in DNA.
It was not until 1953 that scientists Watson and Crick, with the important collaboration of Rosalind Franklin, discovered DNA, which meant a revolutionary change for modern biology. From then on, we were able to understand the code, structure and composition of DNA and the functioning of the evolutionary process from a genetic point of view.
Today, genetic modification processes such as cloning, transgenics or the CRISPR/Cas9 method allow us to modify DNA structures at will and insert specific sequences of information into them, which has generated intense controversy and ethical debate in the scientific environment of modern genetics.
Until recently there was a general classification of living things into kingdoms:
- Bacteria
- Archaea
- Protists (algae and unicellular organisms)
- Fungi (fungi)
- Plantae (modern plants)
- Animalia (animals)
NOTE: previously the so-called mineral kingdom was included, but it has been excluded from the classification since it does not deal with living beings.
Given the complexity of evolutionary processes in living things, the modern (branched) cladistic classification of life is not based on kingdoms but on domains. The three current major domains that encompass the classification of all life are:
- Bacteria (with all its ramifications).
- Archaea (with all its ramifications)
- Eukaryote (with all its branches), this domain includes fungi, plants and animals.
The classification into domains was achieved thanks to the chemical composition of DNA and the similarities between the different individuals identified by Genetics.
Genetics
Genetics works on the basis of a four-letter code: G, A, C and T/U.
- G: corresponds to the molecule Guanine.
- A: corresponds to the Adenine molecule.
- C: corresponds to the Cytosine molecule.
- T/U: corresponds to the molecule Thiamine in DNA and to Uracil in its corresponding RNA (information reading and transfer molecule).
The amino acids are groups generally formed by three molecules of the previous ones, that united in a sequence form the proteins that constitute the base of all that we are.
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