Found the culprit?

Recently, many of my PCR reactions have not been coming up with DNA when I run gels. I've been hoping that this problem would just correct itself or go away, but this was not to be the case. Three PCR reactions in a row failed to produce DNA fragments.

The good news is that I think I've finally found the problem. I used the Vector NTI program on the lab computer to double-check what the annealing temperature of my reaction should be. I had been previously been using 51C, just taking it for granted that it would always work. Vector NTI told me that I should be setting my annealing temperature higher, at 55C.

The reason that this would be a problem is that if the annealing temperature is not high enough, the double-helix DNA strand in my reaction solution might not separate completely, making it impossible for the Taq molecules to move along the strand and produce more DNA copies. Setting the annealing temperature higher will help the strands to separate. I will know tomorrow whether or not the PCR was successful when I run a gel on the reaction products.

In other news, here is an image of my Oleracea plants. The front-right one is the Dwarf 5 phenotype, which has a shrunken stem. Front-left is Dwarf 6, which is instead dwarfed in the shoot near the flower, causing the flowers to have a bunched-up "bouquet" look. I'm not sure which is which, but one of the back plants is Dwarf 1, which may be a hybrid dwarf. The other is the "wild type," or un-mutated genotype.