Table I.

IgVλ diversification in UNG-reconstituted ung^−/− DT40 cells^a

	Gene conversions	Mutations at C:G		Mutations at A:T
		Total	Tv
UNG-WT	14	50	16	13
UNG-D147N	1b	56	0	0

^aThe IgVλ genes were sequenced from the sorted sIgM-loss population from 7 independent transfectants expressing wild-type mouse UNG (52 mutated sequences) and 5 independent transfectants expressing the D147N mutant (29 mutated sequences). All events identified in more than one sequence within a given transfectant population were counted only once to avoid overestimation caused by repeat counting of dynastically related events.

^bThis putative gene conversion event comprises two consecutive C→T transitions; it cannot be definitively concluded that these do not reflect separate single-nucleotide substitutions.