How to make DNA model? (Helix)

[arlindh]

Hey folks,

I need a tutorial/guide in making a DNA model with Illustrator. Have found some short guides on the net but its not enough and not exactly what I was looking for.

At the end it will be something like this:

http://i45.tinypic.com/2uf3p0o.png

but I don't know how to make the helix and most of it.

Really need some help,
Regards