Biotechnology and Bioinformatics (1+1)

Trouble Shooting

Common problems and solutions are summarised in Table1.

Table 1. Common problems  and appropriate solutions

Sl. No.	Problem	Possible causes / solutions
1.	Lysis of the cell is incomplete	Incubation time is not long enough. At least one of the ingredients is lacking in cell lysis solution, especially SDS. Check by shaking the tube, if no foam formation is seen, then add 100 μL of 10%  SDS. If there is foam formation, add 5 μL of Proteinase K (20mg/ml) and continue to incubate for One hour.
2.	No  DNA precipitation	Cell lysis is not complete. Short centrifuge time and/or low speed Wrong precipitation solution (ethanol/ isopropanol)
3.	No DNA on gel	DNA pellet is lost during wash step. The gel was not stained with ethidium bromide.
4.	DNA extraction fail from preserved samples	.The two methods described in this manual are often used to produce reasonably good DNA quality. If these two methods fail, especially when dealing with preserved samples, the best solution is probably to use commercial DNA extraction kits.