Dipteran chromosomes: a simple method for obtaining high quality chromosomal preparations

For cytogenetic studies it is necessary to develop an efficient method of chromosome preparation with wellpreserved and dispersed chromosomes and little or no cell-wall debris. In this study, we describe a method for obtaining high quality chromosomal preparations of dipteran cells. This procedure combines drop method and air-dry technique and produces a cell suspension with separated and mixed cells. Suspended mitotic cells were then dropped onto a glass slide in order to distribute the cytoplasm and spread the chromosomes. We compare and evaluate different chromosome preparation methods to develop a more reliable procedure for the resolution of chromosome characteristics and chromosome bandings in blow fly mitotic chromosomes. The combined drop and air-dry technique described here is convenient for identification of sex chromosomes. Using this protocol, acceptable high-quality chromosomal spreads with flattened cells and no cell debris, and without damage and/or loss of chromosomes were obtained.