Under the genetic code, it is customary to understand such a system of signs denoting the sequential arrangement of nucleotide compounds in DNA and RNA, which corresponds to another sign system that displays the sequence of amino acid compounds in a protein molecule.
It is important!
When scientists managed to study the properties of the genetic code, universality was recognized as one of the main ones. Yes, no matter how strange it sounds, all living organisms are united by one, universal, common genetic code. It was formed over a long time period, and the process ended about 3.5 billion years ago. Therefore, in the structure of the code, traces of its evolution can be traced, from the moment of its inception to the present day.
When it comes to the sequence of elements in the genetic code, it is understood that it is far from chaotic, but has a strictly defined order. And this also largely determines the properties of the genetic code. This is equivalent to the arrangement of letters and syllables in words. It is worth breaking the usual order, and most of what we read on book or newspaper pages will turn into an absurd gibberish.
Basic properties of the genetic code
Typically, the code carries some information encrypted in a special way. In order to decipher the information of the genetic code, it is necessary to know the distinctive features.
So, the main properties of the genetic code are:
- tripletness;
- degeneracy or redundancy;
- unambiguity;
- continuity;
- versatility already mentioned above.
Let us dwell on each property.
1. Triplet
This is when three nucleotide compounds form a sequential chain within a nucleic acid molecule (i.e. DNA or RNA). As a result, a triplet or codon connection is created . This codon encodes one of the amino acids, its location in the chain of peptides.
Codons (they are code words!) Are distinguished by their sequence of compounds and by the type of those nitrogen compounds (nucleotides) that make up their composition.
In genetics, it is customary to distinguish 64 codon types. They can form combinations of four types of nucleotides, 3 in each. This is equivalent to raising the number 4 to the third power. Thus, the formation of 64 nucleotide combinations is possible.
2. Redundancy of the genetic code
This property can be traced when several codons are required to encrypt a single amino acid, usually within 2-6. And only the amino acids methionine and tryptophan can be encoded with a single triplet.
3. Unambiguity
It is included in the properties of the genetic code as an indicator of healthy gene inheritance. For example, doctors who are in sixth place in the chain of the GAA triplet can tell doctors about good blood condition and normal hemoglobin. It is he who carries information about hemoglobin, and he also encodes glutamic acid. And if a person is sick with anemia, one of the nucleotides is replaced by another letter of the code - U, which is a signal of the disease.
4. Continuity
When recording this property of the genetic code, it should be remembered that the codons, like chain links, are not located at a distance, but in direct proximity, one after another in the nucleic acid chain, and this chain does not interrupt - there is no beginning or end in it.
5. Versatility
We should never forget that everything on earth is united by a common genetic code. And therefore, in primates and humans, in insects and birds, a centennial baobab and a blade of grass that barely peeked out from under the ground, similar amino acids are encoded with the same triplets.
It is the genes that contain the basic information about the properties of an organism, a kind of program that the body inherits from those who lived earlier and which exists as a genetic code.