Gel Electrophoresis of DNA fragments produced by apoptosis

[i_love_science]

Homework Statement

One mechanism involved in apoptosis is the digestion of DNA by DNAases. DNA gets digested into fragments of lengths equal to multiples of the distance between nucleosomes.

The figure attached shows the results of separation by gel electrophoresis of the DNA released by the action of DNAase.

Suggest how the pattern in the left-hand column would change if very high concentrations of DNAase were applied to the cells.

Relevant Equations

gel electrophoresis

The answer is that there would only be a 250 bp fragment, and it would be brighter.

I think that there would just more fragments of all sizes, as more DNA is degraded. I don't understand why there wouldn't be fragments of larger sizes. Thanks!

 

[Borek]

Not knowing anything about DNA digestion, but just applying some logic: if there is a fragment longer than the single distance between nucleosomes, what will DNAase do to it?

 

[chemisttree]

...or if you chew your peanuts long and vigorously enough you get a mouthful of peanut butter. Not more chunks of peanuts.