Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published November 1, 1981 | public
Journal Article Open

Transmission electron microscopic method for gene mapping on polytene chromosomes by in situ hybridization

Abstract

A transmission electron microscope method for gene mapping by in situ hybridization to Drosophila polytene chromosomes has been developed. As electron-opaque labels, we use colloidal gold spheres having a diameter of 25 nm. The spheres are coated with a layer of protein to which Escherichia coli single-stranded DNA is photochemically crosslinked. Poly(dT) tails are added to the 3' OH ends of these DNA strands, and poly(dA) tails are added to the 3' OH ends of a fragmented cloned Drosophila DNA. These probe-dA strands are hybridized in situ to polytene chromosome squashes. Gold spheres are linked to the hybridized probe-dA strands by A· T base pairing. The sphere positions relative to the chromosome bands can be observed by transmission electron microscopy. The method shows low background and high resolution.

Additional Information

© 1981 by the National Academy of Sciences. Contributed by Norman Davidson, August 3, 1981. We are indebted to Dr. Welcome Bender for the gift of cDm2848 and cDm2188 DNAs and for much advice and discussion, to Dr. Tony Weil for the pC1T19 DNA, and to Dr. Herschel Mitchell for advice about chromosome preparations. This research was supported by National Institutes of Health Grant GM 20927. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

Files

WUMpnas81.pdf
Files (2.0 MB)
Name Size Download all
md5:e71b808e25478c1a916b1e2856c84780
2.0 MB Preview Download

Additional details

Created:
August 22, 2023
Modified:
October 16, 2023