Which of the following statements about recombinant dna technology is false?
Recombinant DNA is a set of procedures that uses enzymes and various laboratory techniques to isolate, manipulate and combine DNA segments from different organisms. The technique is based on the fact that DNA molecules from all organisms have the same chemical structure and differ only in their nucleotide sequence.
The ability to splice and reinsert DNA into a living cell represents a major breakthrough in biological science. Its development was enabled by a number of key developments such as the discovery in the 1960s by Swiss microbiologist Werner Arber and American biochemist Stewart Linn that bacteria protect themselves from viruses by producing endonucleases (restriction enzymes) which cut DNA precisely at one specific site, thereby preventing virus replication and infection of the host. The identification of these restriction enzymes enabled scientists to isolate pure DNA from plants and animals, which could then be combined with other DNA fragments.
Cloning of recombinant DNA is accomplished by the use of so-called vectors, which are bacterial bacteria that carry DNA fragments and can replicate independently of the host chromosomal DNA. Plasmids are ideal cloning vectors because they contain a selectable marker that enables scientists to distinguish non-transformants from transformants and to isolate recombinant DNA.
The recombinant DNA is then inserted into the genome of a host cell where it becomes integrated into the chromosomes. The integration of genes into a living cell results in the production of recombinant proteins, which can be used for medical, industrial and agricultural purposes. The most common application of recombinant DNA is the genetic modification of crop plants to produce desired characteristics such as insect resistance, herbicide tolerance and increased nutritional value. Several recombinant products are currently on the market including pharmaceuticals that treat anemia, AIDS, cancers and hereditary disorders, vaccines against diphtheria and hepatitis B and C, human growth hormone deficiency and antiviral drugs.
