Amplification of chloroplast DNA using the polymerase chain reaction (PCR): a practical activity for secondary school students

We describe a polymerase chain reaction (PCR) protocol suitable for use in secondary schools and colleges. This PCR protocol can be used to investigate genetic variation between plants. The protocol makes use of primers which are complementary to sequences of nucleotides that are highly conserved across different plant genera. The regions of chloroplast DNA amplified lie between these conserved sequences and are non-coding. These non-coding regions display a high frequency of mutations and show relatively high rates of evolutionary change. Thus it is possible to use the protocol to explore evolutionary relationships between plants. Results from Brassica oleracea can be used to highlight genetic similarity and differences within and across genera. The protocol is robust and is suitable for use either with a thermocycler or a series of water-baths, thus making it accessible for use in most schools and colleges.