Recombinant DNA
Biology: AQA A Level, topic 8.4.1
DNA Fragments
Recombinant DNA is where fragments of foreign DNA are inserted into other sections of DNA.
Universal code
- DNA is made from a sequence of four bases (A, T, C, G).
- Every organism uses the four bases as the genetic code to produce proteins.
- This means that DNA can be considered a universal code.
Recombinant DNA
- The fact that the genetic code is universal means that any section of DNA can be taken from one organism and placed inside another.
- Once the DNA has been inserted, it is then transcribed and translated to produce proteins.
- Transcription and translation are also universal processes.
- The process of transferring sections of DNA produces recombinant DNA.
Fragments
- The sections of DNA that are transferred are called fragments.
- The organism that has received fragments of DNA is said to be transgenic.
Producing DNA Fragments
DNA fragments are sections of DNA that are used to form recombinant DNA. The first step in producing recombinant DNA is producing the fragments.
Target gene
- Recombinant DNA often involves inserting a specific gene of interest into DNA.
- This gene normally encodes a protein that has useful properties.
- The gene that is transferred is called the target gene.
Producing the fragment
- In order to transfer the target gene, it needs to be removed from the DNA in a section called a DNA fragment.
- DNA fragments can be produced in three ways:
- Reverse transcriptase.
- Restriction endonuclease.
- Using a gene machine.
Inserting the fragment
- Once the fragment has been produced, it can be inserted into the genome to produce a transgenic organism.
Test yourself on Recombinant DNA
Which of the following statements about DNA fragments are true?
What is the name given to DNA that is produced from the transferring sections of DNA between organisms?
What are three ways of producing DNA fragments?
What is the first step in producing recombinant DNA?
Which of these is NOT a technique used to produce DNA fragments?