What is "cotransformation"

n. (context biology English) The simultaneous transformation of two marker genes

Cotransformation is the simultaneous transformation of two or more genes.

Only genes in the same chromosomal vicinity can be transformed; the closer together the genes lie, the more frequently they will be cotransformed. By contrast, genes sufficiently far apart that they cannot appear together on a fragment of donor DNA will almost never be cotransformed, because transformation is so inefficient that recipient cells usually take up only a single DNA.