The Human Genome Project (HGP) was a 13-year international research effort aimed at determining the entire DNA sequence of the human genome. The HGP was launched in 1990 and completed in April 2013. This project helped to identify and physically map all the genes of the human genome. The sequence obtained from the HGP has been a very useful point of reference in order to identify and characterize mutations associated with genetic disorders. The HGP predicted approximately 20,500 genes (each of them produces an average of three proteins), which are distributed in the 23 pairs of chromosomes in the cells of our body.
One of the main reasons why there is a need to create additional three kingdoms was due to the invention of the microscope. The scientific device paved way for a more intensive study of the tiny organisms most considered as single-celled which cannot be seen by the naked eye.