Polony Power

Return to main article:

"Polonies" are tiny colonies of DNA, about one micron in diameter, grown on a glass microscope slide (the word itself is a contraction of "polymerase colony"). To create them, researchers first pour a solution containing chopped-up DNA onto the slide. Adding an enzyme called polymerase causes each piece to copy itself repeatedly, creating millions of polonies, each dot containing only copies of the original piece of DNA. The polonies are then exposed to a series of chemically-labeled probes that light up when run through a scanning machine, identifying each nucleotide base in the strand of code, much as dusting with powder allows crime-scene investigators to bring up fingerprints on a surface.

Polonies exert an aesthetic appeal. Above, a portion of a single region of the DNA nucleotide "colonies" as they are processed.
Sequencing of "microbeads," much smaller than polonies. Below, sequences from a messenger RNA molecule.
Images courtesy of George Church and the Lipper Center for Computational Genetics

A laboratory scanner can read a slide with 10 million polonies in about 20 minutes, George Church explains, making this one of the fastest sequencing methods yet devised. The resulting batches of data, however, are as disorderly as a sheaf of pages ripped from a telephone book and tossed in the air. A computer program developed by the Church research-laboratory team puts all in order by checking each page against the genetic equivalent of an intact phone directory: a reference sequence such as the one produced by the Human Genome Project. By using the technique, Church envisions that once a new personal genome is assembled, it could be checked for variations that might cause problems for that individual, or pooled with other genomes for research purposes.           

Click here for the January-February 2004 issue table of contents

You might also like

Centralizing University Discipline

Harvard establishes new disciplinary procedures for campus protest violations.

Five Questions with JoAnn Manson

A veteran women’s health advocate on federal funding cuts

Doctors for Change

Countway Library exhibit explores historic anti-nuclear activism

Most popular

Blanche Calloway, Cab’s Enterprising Older Sister

The success and struggles of a pioneering musician

Harvard Sues Over Funding Freeze

The University takes the Trump administration to federal court.

The New Gender Gaps

What to do as men and boys fall behind

Explore More From Current Issue

The Trump Administration's Impact on Higher Education

Unprecedented federal actions against research funding, diversity, speech, and more

89664

Jessica Shand—Math and Music at Harvard

Jessica Shand blends math and music.

89677

Paper Peepshows at Harvard's Baker Library

How “paper peepshows” brought distant realms to life

89684