Transgenic organisms:

As the functions of individual genes become known, the power of this latest biology can be used to change organisms in predictable and desirable pathways.  Organisms which have been changed through the insertion of a cloned gene are known as transgenic organisms; transgenic plants and transgenic animals are both possible. Like approaches  are  not  only  of academic  importance  but  are  increasingly  searching commercial  applications.   For instance, modified plants with better pest or virus resistance have general attractions for agriculture. Moreover, there are most important ethical considerations which must be applied to the use of this new technology both for plants and even more controversially, for animals (involving humans).

This wealth of knowledge about the genome and its expression and the application of that knowledge rely upon a broad range of recombinant DNA tools and methods. Several of the present-day experimental approaches are extremely sophisticated and are beyond the scope of this introductory text.  Moreover,  the following Topics gives an understanding of some of the core methodology: the ability  to cut DNA at specific  sites using constraint  endonucleases  like restriction enzymes, process which permit the detection of specific DNA and RNA sequences  with great accuracy (nucleic acid hybridization), techniques  for preparing  specific  DNA sequences  in huge amounts  in pure form (DNA cloning) and rapid DNA sequencing. More presently, the development of the polymerase chain reaction (PCR) has revolutionized the field of molecular biology.