PCR

Last week you set up some PCR reactions.... if you are a bit puzzled about what that was all about, read on!

PCR stands for Polymerase Chain Reaction. This is a really neat technique that allows you to amplify up (or in other words, make a lot of) a particular gene that you are interested in.

Here is a youtube video I found about PCR...... it is quite a long video, but it actually explains the principle of PCR really well !!

Last Tuesday you set up PCR reactions to investigate a gene (called SBE1) that has two possible forms - in its 'r' form, it results in wrinkled peas, and in its 'R' form, it produces round peas.

Last week you set up three PCR reactions and these have been put into the thermal cycling machine for you. Here is a reminder of what was in each tube:

• One of the tubes was the control - instead of adding any DNA you added water, so there should be no amplified DNA in this tube
• One tube contained primers for the SBE1 gene, and you added genomic DNA extracted from peas displaying the wrinkled phenotype (i.e. wrinkled peas containing copies of the r gene)
• The other tube also contained primers for the SBE1 gene, but this time you added genomic DNA extracted from peas displaying the smooth phenotype (i.e. smooth peas containing copies of the R gene)

All of the tubes also contained the enzyme that synthesises new DNA (Taq DNA polymerase) and de-oxyribonucleotides (the building blocks for new DNA).

So this week you will receive these three tubes back, and you will use gel electrophoresis to analyse your PCR products...