Recombinant DNA technology (A-level only)

Recombinant DNA technology involves the transfer of fragments of DNA from one organism, or species, to another. Since the genetic code is universal, as are transcription and translation mechanisms, the transferred DNA can be translated within cells of the recipient (transgenic) organism.

Fragments of DNA can be produced by several methods, including:

• conversion of mRNA to complementary DNA (cDNA), using reverse transcriptase

• using restriction enzymes to cut a fragment containing the desired gene from DNA

• creating the gene in a ‘gene machine’.

Fragments of DNA can be amplified by in vitro and in vivo techniques.

The principles of the polymerase chain reaction (PCR) as an in vitro method to amplify DNA fragments.

The culture of transformed host cells as an in vivo method to amplify DNA fragments.

• The addition of promoter and terminator regions to the fragments of DNA.

• The use of restriction endonucleases and ligases to insert fragments of DNA into vectors. Transformation of host cells using these vectors.

• The use of marker genes to detect genetically modified (GM) cells or organisms. (Students will not be required to recall specific marker genes in a written paper.)

Students should be able to: