Microcell fusion

This chapter focuses on microcell fusion. The first documented fusions of somatic cells in culture in the early 1960s resulted in the production of viable hybrid cells and produced a technology that would revolutionize genetic analysis in vitro. Parasexual approaches have been instrumental in the physical mapping of the human genome and in the identification and mapping of genes involved in growth regulation, differentiation, and neoplasia. Microcell fusion is a method of physical mapping which involves the transfer of single or small clusters of intact chromosomes from one cell to another. It is perhaps the most attractive technique for interspecific and intraspecific gene mapping because it affords a way to introduce a single chromosome, rather than the entire genome, from a donor cell into a recipient cell background. The transferred chromosome can be stably retained in the recipient cell background under dominant selective pressure. This type of monochromosomal hybrid has several advantages over whole cell hybrid clones. Microcell fusion is accomplished in five essential steps that include: (1) micronucleation of donor cells, (2) enucleation of the micronucleate cell population, (3) isolation of microcells, (4) fusion of microcells to recipient cells, and (5) selection of viable microcell hybrid clones.