Streaked DNA

[biology_06er]

Hi there,

In class I memba the lecturer saying something bout streaking...I kinda wrote down notes and now I'm trying to google info. about it but just wanna make sure I have it right...is this when the DNA all goes to one side...I tried attaching a picture (in paintbrush and word but cldnt upload it) of what I think streaking means-anyhelp there? Is it correct in saying that all the DNA moves to one side and isnt evenly "spread out" And when I'm searching for info. is there a correct name for it, or is it just streaking? Cos I came across vertical and horizontal streaking? Is this the same thing?

Also is there a specific name for when peaks result on the band of DNA..someting about logged DNA?

Cheers,
b_06er

[TheMaker]

It could depend on the type of Agarose you are using. I've seen good results with some, and bad with others. Try finding a company that offers several different formulation of agarose so you can specifically find a good one to fit the project your working on. Protea Biosciences in WV has a good line...

[TheMaker]

Sorry, I didn't read your post correctly, I thought you were running these gels.

[blcr11]

Usually streaking refers to smearing out over the length of the track. If you have chromosomal DNA contamination or badly sheared DNA, you have DNA of random lengths that won't run as distinct bands on a gel. Sometimes you want this kind of sample, and sometimes not.

[snowcapk]

Streaking can also refer to the phenomenon of sample migrating more slowly along the edges of the lanes. In this gel, you can see in lanes 3 and 4, for example, how the band is "U"-shaped instead of "-"-shaped. (I have seen much worse, but this is what came up on google images.) I have seen it with heavy protein-DNA complexes and long DNA fragments on polyacrylamide gels but it hasn't been a problem in agarose gels for me.

[blcr11]

Hm. I guess I would have called that "tailing" rather than "streaking" but I may be splitting hairs. The background certainly looks streakish to me, but I imagine this is a blot or something that was end-labeled? It's not uncommon to see that kind of background or tailing/streaking, especially if you're forced to load a lot of sample, as you say. If you want to call the whole thing streaking, that's fine with me, too.