Michael R. Pina's Lab Notebook

Lab Notebook

Week 2

a) At around base 80, the upper (blue) DNA sequence has AC whereas the lower (yellow) DNA sequence has GG in the last exon.

b) No, they don't all have to have the same DNA sequence, they just don't have any of the correct pigment sequences or they do not have a promoter region.

c) All of them share the first two exon sequences, labeled in purple and teal; it is in the third exon sequence where they differ. This region is likely responsible for the different colors.

In order to create a blue flower to cross with the red flower, I loaded the Green-2 flower and arbitrarily changed some of the bases in the yellow sequence so that the new folded protein was white, creating a blue flower.

When I crossed my new blue flower with the pre-existing red flower, I got some purple but it was not true breeding. After some thought, I went back to both the blue and red flowers and observed the differences in their upper and lower sequences in order to change both of the DNA sequences so that they were true breeding red and blue, respectively. Crossing these 2 true breeding red and blue flowers yielded all purple flowers.

I was not able to isolate a purple flower that would produce all purple flowers when self-crossed so I began to observe the biochemistry and noticed that Tyr and Phe were the determinates for color in the flowers where Tyr produced blue and Phe produced red. Using this information, I began to play around with the DNA sequence, deleting, adding, or changing certain base pairs (around 80) to see the outcome. Finally, I thought to add both Tyr and Phe together which yielded a mutant purple flower. Mutating both the upper and lower DNA sequences allowed for a true-breeding purple flower.