Under the influence of Sendai Virus,
human fibroblast cells and mouse tumor cells grown together in culture
will fuse to form a heterokaryote, in which the nuclei fuse. Because
the cell machinery is primarily murine, over successive mitotic divisions,
human chromosomes (in blue) are gradually
lost. Eventually, a number of hybrid cell lines are formed that have only
one (Colony A) or a few (Colonies B & C) human
chromosomes, which are readily identifiable. These cell lines can be screened
for the presence of various human biochemical markers, which are then assignable
to the retained chromosome.
