TABLE 6.
Growth of isolated revertants on various selective mediaa
| Dayb | Selection | No. of revertants that grew/no. tested (% that grew)
|
||
|---|---|---|---|---|
| His− medium | Met− medium | Leu− medium | ||
| 2 | His+ | 34/34 (100) | 7/34 (20.6) | 0/34 (0) |
| Met+ | 24/33 (72.7) | 33/33 (100) | 0/33 (0) | |
| Leu+ | 0/50 (0) | 0/50 (0) | 50/50 (100) | |
| 3 | His+ | 150/150 (100) | 5/150 (3.3) | 0/150 (0) |
| Met+ | 49/50 (98) | 50/50 (100) | 0/50 (0) | |
| Leu+ | 0/30 (0) | 0/30 (0) | 30/30 (100) | |
| 4 | His+ | 150/150 (100) | 4/150 (2.7) | 0/150 (0) |
| Met+ | 52/53 (98) | 53/53 (100) | 0/53 (0) | |
| Leu+ | 1/20 (5) | 1/20 (5) | 20/20 (100) | |
| 5 | His+ | 150/150 (100) | 6/150 (4) | 0/150 (0) |
| Met+ | 32/32 (100) | 32/32 (100) | 2/32 (6.2) | |
| Leu+ | 0/41 (0) | 0/41 (0) | 41/41 (100) | |
| 6 | His+ | 84/84 (100) | 7/84 (8.3) | 0/84 (0) |
| Met+ | 22/22 (100) | 22/22 (100) | 0/22 (0) | |
| Leu+ | 0/32 (0) | 0/32 (0) | 32/32 (100) | |
a
Revertants were selected initially for their growth on one type of medium (i.e., medium that lacked one essential amino acid). The cells were regrown on the original selection medium to eliminate background and then checked for their ability to grow on medium lacking the other essential amino acids. The three types of selective medium used in these experiments lacked histidine, methionine, or leucine.
b
Day after the initial plating on which the revertants were isolated.