Figure 2.

Cloning by limiting dilution. Transfected 18.81 cells were subjected to successive rounds of limiting dilution to obtain wells seeded with single cells. From single cells, clones were grown for 13 days. Each number identifies a clone in which the first digits refer to the lineage founder and the following digits represent subclones. For example, 18.6.1 refers to a clone obtained from lineage founder 18 which was subcloned twice generating first clone 18.6 and after 18.6.1. Sequences were obtained directly, without cloning, from PCR products obtained from cDNA.