Restriction enzymes cut at VERY specific sites. E.g. EcoRI cut GAATTC in a staggered fashion. A probe is a
complementary sequence that sticks onto the restriction sites to show where the cuts were made.
Restriction sites could be added and removed due to mutations. E.g. a deletion that removes a site that
decreases the sequence length, or an insertion that increases the frequency length. Triangular lines
indicate identical twins while bent lines indicate non-identical twins.
Sickle-cell anemia is detectable through RFLP. The disease creates a large sized fragment when
compared to normal ones, when the TA is flipped into AT.
There are disadvantages for RFLP analysis. RFLP is usually found through trial and error, takes too long
to locate new sites. They are also di-allelic, not very useful for a large population. RFLP analysis also
requires huge amounts of DNA. The analysis process is also time consuming (isolation, digestion,
electrophoresis and blotting).
PCR solves many of these problems. PCR amplifies the amount of DNA present by a huge amount. The
PCR primers are on the two sides of the DNA segment and are outside of the region that would be
SSLP: simple-sequence length polymorphisms,