What Determines STR Band Spacing and Fluorescent Dye Effectiveness?

[whamola411]

With a given STR profile, what determines the spacing of the groups of the bands, and how is the actual number of tandem repeats determined? Also, what properties must the fluorescent dyes used for labeling the primers have in order to be effective?


3. My initial thinking is that the spacing are the regions of DNA that aren't repeats. I suppose this could be both introns and exons of the DNA. I also believe that the actual number of repeats is determined by the height of the peaks. So the higher the peak, the more repeats are present. Am I correct in my ideas? I would also think that fluorescent dyes need to recognize certain sequences, but I am rather lost on this part. Thanks for your help!

 

[Nino MMP]

Yes, you are correct that the spacing of the bands corresponds to the regions of DNA that do not contain repeats. The actual number of tandem repeats can be determined by looking at the height of the peaks on the STR profile. The fluorescent dyes used for labeling the primers must be able to bind to specific DNA sequences on the fragment, and they must also have the ability to fluoresce when exposed to UV light.