Bio-Rad Sequi-Gen GT Sequencing Cell - Manual (Page 27)

• Total signal artifacts
Many artifacts appear in more than one sub-category. For example, smile patterns can
exist in lane-local or in total signal situations (or both), but rarely appear in set-local. It is
important to distinguish the extent and location of each artifact before trying to analyze or
troubleshoot the anomalous pattern.
1. Lane-local artifacts
Condition Probable Causes Solutions/Preventions
2. Set-local artifacts
Condition Probable Causes Solutions/Preventions
Smiling within sets
Frowning within sets
Funneling within sets
Non-continuous vertical
register
Band spacing compressed within
a set
Film exposure differences within
a set
• Loading wells not straight
within set
• Molarity problems in the sam-
ples of the set
• Loading wells not straight
• Molarity problems in the sam-
ples of the set
• Sample molarity too high, or
contamination
• Sample dependent artifact
• Autoradiographic artifact
• Sample dependent artifact
• Sample dependent artifact
• Pour new gel with better lanes
• Check sample and gel buffers
• Pour new gel with better lanes
• Check sample and gel buffers
• Check sample and gel buffers
Smiling bands
Frowning bands
Complex (curvy) bands
Funneling or lane narrowing
Lane widening
Variations in signal intensity
along the lane(s)
Band spacing compressed or
stretched
• Loading wells not straight
• Sample molarity too high
relative to gel
• Sample overloaded
• Sample was allowed to diffuse
into gel too long before
electrophoresis
• Loading wells not straight
• Sample molarity too low rela-
tive to gel
• Sharkstooth comb inserted too
far into the gel
• Loading wells not straight or
clean
• Bubble in gel
• Sample molarity too high
• Sample molarity too low
• Sample dependent artifact
• Check sample and gel buffers
• Sample dependent artifact
• Allow gel to polymerize more
completely before removing
comb
• Check sample and gel buffers
• Reduce sample load volume
• Load a set or two at a time
• Pour new gel with better lanes
• Check sample and gel buffers
• Touch the top of the gel with
the teeth
• Allow gel to polymerize more
completely before removing
comb
• Pour new gel without bubbles
• Check sample and gel buffers
• Check sample and gel buffers
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