Re: Sequencing and oligonucleotides

Sheryl Christofferson (sherylc@omrf.ouhsc.edu)
Mon, 26 Apr 1999 09:15:09 -0500

Greetings Alain:
We have noticed that the main causes for bad sequencing results are: 1) poor
quality template. This mainly involves salt, alcohol, or EDTA remaining in
the prep. 2) secondary structure. We have resolved much of this using ABI's
dGTP reagent kit.

We dilute our primers to 3.2 pmol/ul in water, and then use 1 ul per
reaction. I don't know how much TEA or Amm acetate salts would be present in
this small amount, but it doesn't seem likely to cause trouble. Sequencing
primers should have a melting temperature of at least 50 degrees C. The
background might come from non-specific binding of the primer.

Let me guess: Bad sequencing results are YOUR fault, right?

Sheryl

OMRF DNA Sequencing Facility
Oklahoma City, OK
www.omrf.ouhsc.edu
sherylc@omrf.ouhsc.edu

Alain Laurent wrote:

> Hello ABRF's users
>
> We recently had a complaint about HPLC purified oligonucleotides used for
> sequencing. The hybridization versus the target seems OK but there is a
> strong noise background on the electrophoregram making the reading
> difficult. Do you think that triethylammonium or ammonium acetate salts
> used for HPLC purification
> could be responsible for this effect ? I don't know if this can be a
> plausible explanation for unsuccessful sequencing ?
> By the way do you know the main causes for bad results in sequencing ?
>
> Thank You
>
> **************************
>
> Alain LAURENT Ph. D
> Oligonucleotide Chemistry
> ESGS Groupe CYBERGENE
> 11 rue Claude Bernard
> 35400 SAINT MALO
> FRANCE
> Tel: +33 (0)2 99 21 90 40
> Fax: +33 (0)2 99 21 90 41
> e-mail: a.laurent@eurosequence.com
> http://www.eurosequence.com
>
> ***************************