Recombinant DNA (Cambridge International A-Level Biology)

Spec point — 19.1.1 · define the term recombinant DNA

Recombinant DNA

• The genetic code is universal, meaning that all organisms use the same four nitrogenous bases (A, T, C & G) in the same triplet code
• This means that the same codons code for the same amino acids in all living organisms (meaning that genetic information is transferable between species)
• Thus scientists have been able to artificially change an organism's DNA by combining lengths of nucleotides from different sources (typically the nucleotides are from different species)
• The altered DNA, with the introduced nucleotides, is called recombinant DNA(rDNA)
• If an organism contains nucleotide sequences from a different species it is called a transgenic organism
• Any organism that has introduced genetic material is a genetically modified organism (GMO)

Exam Hint It is because of the universal genetic code that recombinant DNA can be formed. All forms of life use the same genetic code, which is the strongest piece of evidence for evolution. Remember, the genetic code is the basis for storing instructions that, alongside environmental influences, dictate the behaviour of cells and as a result, the behaviour of whole organisms.