CIE A Level Biology复习笔记19.1.1 Recombinant DNA

• The genetic code is universal, meaning that almost every organism uses the same four nitrogenous bases – A, T, C & G. There are a few exceptions
• This means that the same codons code for the same amino acids in all living things (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)

Illustration of a maize plant that has recombinant DNA (DNA from Bacillus thuringiensis)