Table 1.

Focus formation by clones in 1° assays of cells from LDPs

Clone	Series no. (no. passages)
	1 (5)	2 (11)	3 (21)	4 (37)	5 (41)	6 (56)
1A	4*–7	10*–0	11*–1	0–6 M	0–41 M	0–130
3F	0–0	0–3	0–5	0–17 M	1*–15 M	0–130
2B	0–0	0–8	0–2	0–4 M	0–59 M	0–3
6H	0–0	0–17	0–10 M	0–3 M	0–46	0–44
4B	0–0	0–0	0–0	0–0	0–0	0–14B
3E	0–0	0–0 M	3*–2	0–17 M	0–2 G	20**–TNTC
A′†	ND	ND	ND	0–0	0–0	ND

The first number of each pair denotes dense foci (≥1 mm unless noted with ∗), the second number denotes light foci. 1° assays on the uncloned A′ cultures were done only in parallel with the fourth and fifth series and were negative for dense and light foci. See photograph in Fig. 2. ∗, ≪1 mm; ∗∗, <1 mm; M mottled; G, grainy; B, one broad moderate focus; TNTC, too numerous to count; ND, not done. 

^†, Uncloned parental culture.