Experiment and Results Sample 100 ng/µl DNA was extracted from the cricket Acheta domesticus using the phenol-chloroform methods described in Davies et al., 2012 [15], dissolved in Tris-HCl-EDTA (TE) buffer and kept frozen at -20˚C. In initial tests, portions of the extracted DNA were suspended at the same DNA concentration as the control sample in solutions of magnesium chloride, magnesium sulfate, ammonium sulfate, lithium chloride, and nickel chloride. Each salt was mixed in three different concentrations, including 100 mM, 10 mM, and 0.1 mM. Then DNA in each salt concentration was incubated at different temperatures: 25˚C, 42˚C, 65˚C, and 95˚C, for fifteen minutes. The products were then loaded onto an agarose gel and allowed to run in …show more content…
The general pattern was thus: all DNA samples remained intact for all salt concentrations at 25˚C, 42˚C, and 65˚C, as the sample delta brightness was within one standard deviation of or significantly brighter than the average control brightness value; this indicates that the treated DNA was not degraded from its previous genomic state by the applied treatments. All samples were also to various degrees destroyed at 95˚C, as the delta brightness was very low and thus experimentally obtained brightness results differed little from the background luminosity. Judging by a strictly qualitative analysis, replacing the Cl - ion bonded with Mg 2+ with SO4 2- had a minimal effect on DNA quality because of both molecules ' negative charges that are repelled by similar negative charges in the DNA backbone, but it is evident that magnesium sulfate preserves slightly more of the 10kb DNA sample than does magnesium chloride at 95˚C, as is evident when comparing the last 3 lanes of the bottom rows on gels displayed in Figures 1 and 2. Ammonium sulfate, rather than displaying the banded pattern of magnesium sulfate, exhibits an even smearing pattern, as evidenced by the same bottom lanes in Figure 3; however such information cannot be deduced from the values obtained by