Meaning of Genetic Code

What is Genetic Code :

By genetic code we know the set of rules that determine the way in which the genetic information contained in the DNA is translated so that the RNA can convert it into the amino acids of a protein.

In the media, the meaning of genetic code is often confused with that of genotype, genome and DNA, which is why they use it as a synonym.

However, it is necessary to keep in mind that the set of relationships between codons and amino acids is called the genetic code and not the DNA or genotype itself.

genetic code

DNA and RNA are made up of nucleotides. In DNA, the nucleotides are adenine (A), guanine (G), thymine (T), and cytosine (C). In RNA, thymine is replaced by uracil (U).

The process of “reading” the genetic code is carried out in two steps, which are the transcription and the translation. The key to execute these processes is in the complementarity of the nucleotides; that is, each nucleotide in a DNA chain is complemented by another, thus, adenine only pairs with thymine (AT) and guanine only pairs with cytosine (GC).

The transcription refers to the process by which DNA information is transcribed into messenger RNA (mRNA). This is as if we were transcribing an old text into a digital version.

In the translation, the nucleotide sequence in the mRNA is decoded into an amino acid sequence that ultimately forms a protein. In this case, it is as if we were translating a text from Spanish to Japanese, where the characters are different.

Characteristics of the genetic code

To facilitate its understanding, we must point out the main characteristics of the genetic code. Let’s see.

  • Three nucleotides in a row form a codon or triplet, which corresponds to an amino acid.
  • It is degenerate, this means that each amino acid can be encoded by several codons.
  • The reading of the code is continuous.
  • Does not overlap or overlap. That is, each nucleotide is part of a single triplet.
  • It’s universal. This means that, in all living beings, a certain codon corresponds to just the same amino acid.
  • There are start codons for protein synthesis (AUG) and end of synthesis (stop: UGA, UAA, UAG).
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