IUBio

DNA-Sequencer

John Barlow john_q_barlow at hotmail.com
Sat Apr 24 10:30:09 EST 1999


In article <7fp7d6$io7 at net.bio.net>, d.maede at knuut.de says...
>
>Hi,
>
>We intend to buy an sequencer. Thinking about which sequencer to choose,
>I have some questions:
>
>Has anybody out there performed quantitative PCR with labeled primersand
>mesuring the band intensity with an sequencer?
>
>And, what are the disadvantages of a PE 310 and a LI-COR?
>
>Who is working with the new Beckman System and how does ist work
>compared with other sequencers?
>
>Thanks in advance.
>
>Dietrich
>

Hi:
Some time ago I posted a message requesting information about the Beckman and 
the 
Visible Genetics (VisGen) instruments.

I got only two replies about the Beckman.  In essence, this may be a very good 
instrument when the basecalling will be re-designed.  At present, it either 
omits 
questionable bases or selects a base, even when an obvious ambiguity or 
heterozygote is 
present.  One of my responders from Georgia recently compared the same DNA 
templates on the ABI 377 with Big Dyes with the Beckman.  The difference was 
quite 
big in the sensitivity (amount of template necessary to get a readable 
sequence) an, as 
explained above, in the basecalling.  It is possible that with improved 
software the 
Beckman will seriously compete with ABI's products.

I got five responses from people that had a chance to use or purchased the 
Visible 
Genetics Blaster, Clipper, or the new long-read instruments.  Their opinion was 
universally negative.  This is not surprising, because the Visible Genetics 
instrument are 
single-color and have problems with aligning (merging) the lines, just like the 
old ALF 
instruments had.  The OpenGene software from this company as not only providing 
very 
bad basecalling but also being very user-unfriendly particularly appalled most 
users.

I like the ABI 310 and I used it a lot.  Personally, I think that this 
instrument is a bit too 
slow and too expensive.  If purchasing an ABI 377 were not an option, then a 
better deal 
would be to send your specimens to a sequencing facility for a fee.

LiCor's instrument should perform well, because of clearly superior design with 
the 
infrared dyes and low noise.  However, I did not use this instrument and I did 
not talk 
directly to anyone that used it.

In summary, I would advise you to get an ABI 377 or to wait another year for 
the 
Beckman.


John




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