Gel Electrophoresis Case Study

Based on the gel electrophoresis of genomic DNA of wild type and eyeless flies shows only DNA in wild type and not in eyeless (Figure 1). The reason to explain why eyeless did not show any DNA on the gel is the preparation of samples for PCR. The wrong amount of reagents might have been added or left out. Another case is no DNA was collected from eyeless flies. Since there was no DNA for eyeless, another group’s eyeless DNA was used throughout the lab. For Figure 2, Wild type shows both blue and white colonies and eyeless show only white colonies (Figure 2). In blue-white screening it detects for recombinant bacteria by presence of the activity of beta-galactosidase enzyme occurring in Escherichia coli which cleaves lactose into glucose and galactose producing X-Gal, the blue pigment.

The reason eyeless colonies were only white might have been to nonfunctional lacZ gene resulting no production to X-Gal or the efficiency of ligation was to great that it transformed all bacteria. The gel electrophoresis from Figure 3 shows wild type and eyeless samples had DNA from the isolated plasmids from bacteria (Figure 3). This allowed the samples to be sequenced. Figure 4 shows only wild type-SP6 sequence to have the eyeless gene on exon 2 and 3, while the other sequences do not have the eyeless gene (Figure 4). This result makes this whole experiment invalid to conclude what mutations are stemmed in eyeless mutant because there is no location of the gene in eyeless sequences with either primer of SP6 or T7. The reason the eyeless sequences did not show any eyeless gene might be because in the blue-white screening there was no blue colonies only white ones, possibility due to the reason the colonies were ampicillin