Table 2.

Leu⁺ reversions under selection were cell density-dependent

	Description	Number of micro-drops or plates with Ni papillae
		Day 2	Day 4	Day 7	Day 11	Day 15	Day 18
A	8.27 × 107 cells/micro-drop	N0 = 589	N0 = 501	N0 = 475	N0 = 462	N0 = 344	N0 = 264
	Total micro-drops = 620	N1 = 29	N1 = 108	N1 = 125	N1 = 116	N1 = 199	N1 = 246
	Total cells = 5.13 × 1010	N2 = 2	N2 = 11	N2 = 13	N2 = 20	N2 = 49	N2 = 63
				N3 = 7	N3 = 9	N3 = 23	N3 = 31
					N4 = 3	N4 = 5	N4 = 13
							N5 = 3
	Papillae/micro-drop	0.053	0.210	0.277	0.315	0.619	0.858
B	8.27 × 107 cells/plate	N1 = 6	N1 = 8 N2 = 1	N1 = 8	N1 = 8	N1 = 7	N1 = 7
	Total plates = 50			N2 = 2	N2 = 2	N2 = 2	N2 = 2
	Total cells = 4.20 × 109					N3 = 1	N3 = 1
	Papillae/plate	0.12	0.20	0.24	0.24	0.28	0.28
C	8.27 × 106 cells/micro-drop	N0 = 1600	N0 = 1600	N0 = 1600	N0 = 1599	N0 = 1598	N0 = 1598
	Total micro-drops = 1600				N1 = 1	N1 = 2	N1 = 2
	Total cells = 1.32 × 1010
	Papillae/micro-drop	0	0	0	0.001	0.001	0.001
D	8.27 × 107 cells/micro-drop	N0 = 160	N0 = 154 N1 = 6	N0 = 152	N0 = 145	N0 = 137	N0 = 127
	Total micro-drops = 160			N1 = 8	N1 = 15	N1 = 23	N1 = 33
	Total cells = 1.32 × 1010
	Papillae/micro-drop	0	0.038	0.05	0.094	0.144	0.206
E	2.96 × 108 cells/micro-drop	N0 = 45	N0 = 41	N0 = 33	N0 = 21	N0 = 11	N0 = 8
	Total drops = 125	N1 = 38	N1 = 39	N1 = 42	N1 = 40	N1 = 45	N1 = 42
		N2 = 24	N2 = 24	N2 = 27	N2 = 37	N2 = 40	N2 = 38
		N3 = 11	N3 = 12	N3 = 13	N3 = 12	N3 = 13	N3 = 19
		N4 = 6	N4 = 7	N4 = 8	N4 = 12	N4 = 11	N4 = 12
		N5 = 1	N5 = 2	N5 = 2	N5 = 3	N5 = 5	N5 = 6
	Papillae/micro-drop	1.18	1.29	1.42	1.70	1.90	2.02
F	2.96 × 108 cells/micro-drop	N0 = 125	N0 = 125	N0 = 125	N0 = 125	------	------
	Total drops = 125
	Papillae/micro-drop	0	0	0	0	-----	------

A,C,E: Cells were deposited as micro-drops on MM+P plates. B: Cells were spread on MM+P plates. D: cells were pre-cultured in 0.85% NaCl solution for 14 hours at 37°C before deposited as micro-drop on MM+P plates. F: Cells were deposited as micro-drops on MM+P plates with 100 μg/ml Ampcillin. Ampicillin was added once a day with 1 ml (1000 μg/ml) around the every micro-drops till day 7.