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Biology 2nd Baccalaureate

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10.3. Gene concept

What is a gene?

The concept of gene has changed over time:

Mendelian concept of gene

The genes or hereditary factors that Mendel (1865) described is a unit of function, structure, transmission, mutation and evolution that is distributed in an orderly and linear manner in the chromosomes that is passed from parents to children.

Although the word gene was used for the first time in 1909, according to the Mendelian concept, genes are discrete and indivisible particles that are arranged linearly on chromosomes.

Around 1950, there was the concept that the gene is a piece of the DNA chain that directs the synthesis of a protein. This is a concept that provides a molecular or structural nature to the gene. The gene encodes proteins and must have a structure defined by the linear order of its triplets or codons .

Molecular gene concept

The gene is still the unit of function, but the gene is no longer the unit of mutation and the unit of recombination, but the unit of mutation and recombination is a nucleotide pair.

It is currently known that some genes contain the information to synthesize more than one polypeptide and that a protein can be encoded by a set of different genes.

The concept of gene was modified when it was understood that genes could also determine non-enzymatic proteins and also individual polypeptide chains (protein subunits) and the various types of RNA involved in protein synthesis.


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Biology and Geology teaching materials for Compulsory Secondary Education (ESO) and Baccalaureate students.