How to Make Nucleotide Ladder Markers?

[Duncan Clark]

Historians believe that in newspost <co57q301hgj at drn.newsguy.com> on 
Thu, 25 Nov 2004, Bert Gold <Bert_member at newsguy.com> penned the 
following literary masterpiece:
>How would you make a ladder that
>consists of: 60, 70, 80, 90, 100,
>120, 140, 160, 180, 190, 200, 220,
>240, 260, 280, 300, 320, 340, 360,
>380, 400, 420, 440, 460, 480, 500,
>520, 540, 560, 580, 600, 620, and
>640 nucleotides?

Umpteen individual PCRs - watch out for the +A addition?

Or mutate or gene synthesise a DNA that has say C only at those 
positions. Use a single fluorescent ddGTP sequencing reaction so only 
those positions light up?

In the latter case you can't use a fluorescent primer as you will 
generate a fluorescent run-off product much much brighter than the 
fragments you require.

Duncan

-- 
I love deadlines. I especially like the whooshing noise they make as
they go flying by.

Duncan Clark
GeneSys Ltd.