ABSTRACT
Conventional cytogenetic analysis is based on the examination of dividing cells. For some sources, such as peripheral blood, stimulation of the nucle ated lymphoid cells is necessary to induce division, or mitosis . The stimu lated culture then yields dividing cells with analyzable chromosomes that can be arrested in metaphase. For sources such as bone marrow with a higher fraction of cells which divide spontaneously, both unstimulated cultures (di rect preparation) and short-term cultures with stimulants are employed.