GENE
Gene is a region of a DNA molecule with a specific function. For a long time this term was considered as meaning an indivisible unit of heredity. After that gene was thought to be a continuous section of a DNA, where information of an amino acid sequence of one protein is recorded as a nucleotide sequence. At present the concept of gene is not so categorical. It is a continuous region of a DNA that in some cases corresponds only to a part of a protein chain, in other cases - to a whole protein molecule.