Localization of actin-related sequences by in situ hybridization to R-banded human chromosomes

Using a cytoplasmic actin cDNA probe we have localized a number of actin sequences in the human genome using a novel in situ hybridization technique. Metaphase chromosomes treated to produce R-bands were directly annealed with 125I-labeled actin probe. Under these conditions many regions of the genome were apparently denatured enough to be capable of hybridizing with the probe. Most of the actin sites detected in prior experiments using chromosome preparations, which had been completely denatured, were recognized in this experiment. The major advantage of this method over standard in situ hybridization techniques is the marked increase in the resolution of subregional localization.