[A new explanation for shadow bands on denaturing PAGE for products of STRS--the difference between sense and antisense strands in electrophoresis].
OBJECTIVE
To explore the mechanism of shadow bands on denaturing PAGE for PCR products of STR sequences and try to eliminate them.


METHODS
PCR and asymmetric PCR were employed. The amplified fragments were separated on denaturing PAGE and visualized by silver stain.


RESULTS
By asymmetric PCR, half of shadow bands of dinucleotide repeats were eliminated and there was only one band for each allele for tetranucleotide sequence. A different migration between the sense strand and antisense strand was identified.


CONCLUSIONS
The difference between sense and antisense strands in electrophoresis is one of the causes in shadow bands, and these shadow bands can be eliminated by asymmetric PCR partly or totally.
Zhao
H
H
Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical college, Beijing 100005 P.R.China. huangsz@263.net
Huang
S
S
Li
H
H
Liang
C
C
Yuan
B
B
D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D016133:Polymerase Chain Reaction; D020080:Tandem Repeat Sequences