Printer Friendly

Sequencing DNA using remote Braille.

Sequencing DNA using remote Braille

Using the fine tip of a scanning tunneling microscope as a teensy surrogate finger for feeling and recording the atomic bumps and valleys of molecules, two chemists have reconstructed images of synethic strands of DNA. In the Nov. 9 NATURE, David D. Dunlap and Carlos Bustamante of the University of New Mexico in Albuquerque suggest they may be able to improve the techique enough to enable geneticists to directly determine the sequence of nucleotide building blocks that make up strands of DNA. They envision looking at graphic reconstructions of the strands and reading off the nucleotides like letters in a sentence. DNA sequencing presently involves time-consuming and less direct biochemical techniques.

In their experiment, the New Mexico scientists coated a specially prepared graphite surface with a single layer of polydeoxyadenylate molecules, or poly(dA)--chain-like DNA molecules composed solely of the nucleotide building block deoxyadenylate. The researchers produced images that clearly show the constituent nucleotides' two chemical rings attached to an equally visible molecular backbone of poly(dA) strands.

Impressive as the images are, the researchers say they still aren't clear enough to allow investors to distinguish among all four nucleotides in the more complicated DNA molecules in cells. Other hurdles include rendering each of a DNA strand's many nucleotides completely accessible to the tip of the scanning tunneling microscope and preventing more complicated and often complementary DNA strands from forming into double strands once they deposit onto the graphite surface.
COPYRIGHT 1989 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1989, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Publication:Science News
Date:Nov 25, 1989
Previous Article:Fishing for current with an STM rod.
Next Article:An AIDS-associated microbe unmasked.

Related Articles
Custom design for DNA snippers.
Genes (and proteins) in the bank.
A novel way of editing genetic messages.
Gene-duplicating proteins isolated.
DNA links gold into new materials.
The Meaning of Life.
Genes, genes, and more genes.
Poodle DNA compared with that of mice, people.
Non-invasive method to obtain DNA from freshwater mussels (Bivalvia: Unionidae).
Cryptosporidium hominis infection of the human respiratory tract.

Terms of use | Privacy policy | Copyright © 2020 Farlex, Inc. | Feedback | For webmasters