Gene technology is the artificial manipulation of genes
Gene technology’s use different techniques:
TOOLS:
Restriction enzyme
Enzyme that are used to cut DNA at specific sequences
‘Like a pair of scissors’
One of the most important tools in genetic engineering
They have the ability to cut DNA molecules at precise sequences of 4 to 8 base pairs called recognition sites
A lot of bacteria are used to get restriction enzymes
Bacteria use restriction enzymes as a defence mechanism
We use over 1000 restriction enzymes today that engineers are able to: * isolate DNA * sequence DNA * manipulate individual genes
The site at which the DNA is cut may result in overhanging ‘sticky ends’ or overhanging ‘blunt ends’. Sticky ends only join to complimentary base sequence
A restriction enzyme cuts a double stranded molecule at its specific recognition site
You need to use the same enzyme to have the correct base pairs
It is possible to use restriction enzymes that cut leaving no overhang – a so-called ‘blunt end’
DNA is cut in such a way it is able to be joined to any other end fragment but tends to be non-specific because they are no sticky ends as recognition sites – we won’t know what protein is produced, it is hard to cut this way because you need exactly the gene sequence because if you don’t then you change the sequence and amino acids produced.
Ligase
Join DNA fragments
DNA fragments produced using restriction enzymes may be reassembled by a process called ligation. Pieces are joined together using an enzyme called DNA ligase
LIGASE IS AN ENZYME
DNA of different origins produced in this way is called recombinant DNA, because it is DNA that has been recombined from different sources
The combined techniques of using restriction enzymes and ligation are the basic tools of genetic engineering
Plasmid is a circular piece of DNA from bacteria
Two pieces of DNA are cut using restriction enzymes.