TABLE 3.

Rates of plasmid loss observed with CDEI mutant centrometers (sectoring assay)

Plasmid	Total no. of coloniesa	Mean frequency of loss (± SD)/ cell divisionb	Relative frequency of loss
pBM-WT	2,927 (2)	1.6 (±1.2) × 10−2	1
pBM-Δ200	7,663 (3)	2.8 (±0.4) × 10−2	1.75
pBM-Δ292	8,791 (4)	3.3 (±0.7) × 10−2	2
pBM-ΔID	7,504 (3)	7.8 (±1.0) × 10−2	4.9
pBM-ΔIR	8,926 (4)	8.3 (±1.6) × 10−2	5.2
pBM-ΔIE	6,469 (3)	6.7 (±0.4) × 10−2	4.2
pBM-ΔID-Δ200	3,429 (3)	2.5 (±1.1) × 10−1	15.6
pBM-Δ308	693	++	NDc
pBM-ΔCEN	763	++	ND

^aNumbers in parentheses are numbers of independent experiments whose results were summarized. 

^bLoss rate/cell division = number of half-sectored colonies/(total number of colonies − number of red colonies). ++, too high to quantitate by the sectoring assay. 

^cND, not determined.