Theory
This method relies on PCR to differentially amplify non-homologous DNA regions between digested fragments of two nearly identical DNA species, that are called 'driver' and 'tester' DNA. Typically, tester DNA contains a sequence of interest that is non-homologous to driver DNA. When the two species are mixed, the driver sequence is added in excess to tester. During PCR, double stranded fragments first denature at ~95°C and then re-anneal when subjected to the annealing temperature. Since driver and tester sequences are nearly identical, the excess of driver DNA fragments will anneal to homologous DNA fragments from the tester species. This blocks PCR amplification and there is no increase in homologous fragments. However, fragments that are different between the two species will not anneal to a complementary counterpart and will be amplified by PCR. As more cycles of RDA are performed, the pool of unique sequence fragment copies will grow faster than fragments found in both species.
Technical aspects of how amplification occurs using universal adapters is described below in greater detail.
Read more about this topic: Representational Difference Analysis
Famous quotes containing the word theory:
“Lucretius
Sings his great theory of natural origins and of wise conduct; Plato
smiling carves dreams, bright cells
Of incorruptible wax to hive the Greek honey.”
—Robinson Jeffers (1887–1962)
“There never comes a point where a theory can be said to be true. The most that one can claim for any theory is that it has shared the successes of all its rivals and that it has passed at least one test which they have failed.”
—A.J. (Alfred Jules)
“Freud was a hero. He descended to the “Underworld” and met there stark terrors. He carried with him his theory as a Medusa’s head which turned these terrors to stone.”
—R.D. (Ronald David)