The functional unit of inheritance based upon the coding of DNA molecules, and occupying a fixed locus on a chromosome (see figure below), which directs the synthesis of a particular protein. It consists of a sequence of base pairs that correspond to a specific sequence of amino acids constituting a protein. Genes function to build somatic cells (i.e., a structural gene) or to regulate the expression of other genes (i.e., a regulator gene). According to evidence from the Human Genome Project, the human genome contains about 32,000 genes (only 10,000 more than the ‚aahumble‚aa worm), encoded in some 4 billion base pairs. It was Wilhelm Johannsen ((1857-1927) who coined the term ‘gene’ in 1909.
