WHAT IS SOUTHERN BLOTTING? A process used for DNA analysis Developed by Edwin Southern in 1975 Is also referred to as DNA blotting Edwin Southern
USE IN GENETICALLY MODIFIED ORGANISMS In genetically modified organisms, Southern blots are used to make certain that the necessary section of DNA has been inserted into the genome of the organism being modified.
STEP 1 DNA is separated from it’s source and cut with a restriction enzyme.
STEP 2 The fragments are put into a gel and are sorted by electrophoresis in order of length, the shortest at the top and the longest at the bottom.
STEP 3 Ethidium bromide is then used to make the fragments visible, and the DNA is taken from the gel and placed in a nylon filter.
STEP 4 Then a radioactive probe is added, which binds to complementary DNA fragments.
STEP 5 The nylon membrane is then covered with an X- ray film which, when developed, reveals the position of the radioactive probe.