Question

Samples A and C came from the same mouse; however, sample A was from liver tissue while sample C comes from kidney tissue. Describe the difference between the results for these samples and give a potential reason explaining this difference.

Hint: Recall that DNA can be cleaved as seen with restriction enzymes

it is a question from my lab activity gel electrophoresis and DNA extraction

Answer 1

In any organism thousands of cells are present. these cells are originated from zygote, hence they all contains the same DNA content. the only difference is that they have different expression pattern of genes in different tissues.

now, if we isolate DNA from different tissue like liver, kidney, heart etc, they will have same type of DNA in all cells. if we digest the DNA isolated from liver and kidney of same organism (mouse), they will produce same type of fragments because they basically contains same DNA with different set genes being expressed.

if we load digested mouse genomic DNA on agarose gel, it will be appearing as smear fluorescing through out the lane. if we detect fragment using some DNA fragments as probe through southern hybridization, the digested DNA  will show same type of pattern on southern blot of genomic DNA isolated from, liver and kidney.