The third panel down has a problem with +A addition. The +A didn't go to completion for this sample. +A is an artifact of any PCR it doesn't matter if its a dinucleotide or tetranucleotide. Do you do a final extension step for 10 to 30 minutes? This can help sometimes. Also, double check your that all your red markers are sized correctly. The last panel looks as if it is called as 102 in the screen capture but looks as if it is actually more like 163. If you aren't using a high density marker such as HD-400 ROX try using it.
Not sure if this is helpful or not.
Good Luck!
Bob Chadwick
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