ABSTRACT:
The basic assumption of these rules is that, each heritable property of an organism is controlled by a factor called a gene, which is a physical particle present somewhere in the cell. The idea that gene reside in chromosome was proposed by W.Sutton in 1903 and received experimental backing from T.H.Morgan in 1910. Morgan and his collegues then developed the techniques for gene mapping, and by 1922 had produced a comprehensive analysis of the relative position of over 2000 genes on the four chromosomes of the fruit fly, Drosophila melanogaster. The discovery of the role of DNA was a tremendous stimulus to the genetic research, and since then many famous biologists contributed to the second great age of genetics. PCR has made easier many of the techniques, extended the range of endeavor out side of its traditional range of medicine, agriculture and biotechnology. These all techniques led to massive genome sequencing projects, including human genome project which was completed in 2000. Pseudomonas Aeruginosa is a Gram- negative, rod –shaped bacterium that grows in soil, The emergence of Pseudomonas Aeruginosa as a major opportunistic human pathogen during the past century may be a consequence of its resistance to the antibiotics and disinfectants that eliminate other environmental bacteria. A clone is a replica of all or part of a macromolecule (eg: DNA). Cloning a gene means to extract a gene from one organism (for eg: by PCR) and insert it into a second organism (usually via a vector), where it can be used and studied.