Strange CEPH sizing on 377 gels

From: Alison Brown (alison.brown@channing.harvard.edu)
Date: Wed Feb 28 2001 - 13:59:20 EST

We are running microsatellite markers on ABI 377 gels and are sometimes
seeing our CEPH samples appearing at different sizes on either ends of
the gel - but only for certain primers within the pool not all of them.
Our primers are not pigtailed so we are having to treat the pooled PCR
products with T4 polymerase to get rid of plus A artifacts. The first
and last loaded sample are CEPH 1347-02 - at one side of the gel they
are called correctly and on the other end they are 2 base pairs larger.
The size standards have all been called correctly in Genescan. Is this
a T4 problem - bear in mind not all PCR products in the pool are
affected? Has anyone else seen this? Should we switch to pigtailed
primers?

Thanks in advance for ANY help!
Alison 

--
Alison Brown
Channing Laboratory
181 Longwood Avenue
Boston, MA  02115

Ph: 617-732-5561
Fax: 617-264-5135
Email: alison.brown@channing.harvard.edu

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