Identification of a marker chromosome in a rat ascitic tumor by flow cytometry using a modified method for preparing chromosome suspensions.

Preparation of good chromosome suspensions is a crucial step in obtaining good flow karyotypes from different types of cells. Although several methods are in use, not all are suitable for all cell types. Primary cells from murine tissues are specially difficult to flow karyotype. We have modified the existing protocols for preparing chromosome suspensions from the Zajdela ascitic hepatoma (ZAH) cells of rat and have constructed their flow karyograms. Our karyograms show a distinct marker chromosome in these cells, which could not be resolved using other protocols. We have also used this method for preparing chromosomes from the bone marrow cells of the rat and have compared their flow karyograms with the ZAH karyotype. We expect that our protocol will be useful for studying other types of tumor and normal cells.