A powerful feature of BCT is the ability to simulate chemotactic mutants of any desired genotype. A large number of mutants have been constructed in the laboratory and their phenotypes (swimming behaviour in the absence of stimuli) determined. They provide a benchmark against which to compare the output of BCT. Of the 65 known mutant phenotypes listed on this page, BCT qualitatively, if not closely, reproduces the phenotype of 63. It can also make phenotype predictions that can be tested experimentally. Correct predictions would provide further confirmation of the current chemotaxis model, whereas incorrect predictions might indicate areas where the model needs to be refined.

 

Mutant tables

Symbols and their numerical representation in BCT

- = deletion
t = trace (5% of wild-type expression)
+ = wild-type expression
++ = 10-fold overexpression
+++ = 20-fold overexpression
++++ = 30-fold overexpression

tm = tumbling bias (significantly less than wild-type)
wt = wild-type bias (0.85)
sm = smooth-swimming bias (significantly greater than wild-type)

Phenotypes that BCT does not reproduce well are shaded in pink for a near miss and red for way off-target.

 

Single null mutants

Genotype Observed BCT 4.4
T- sm 1.00
R- sm 1.00
B- tm 0.00
W- sm 1.00
A- sm 1.00
Y- sm 1.00
Z- tm 0.00

 

Multiple null mutants

Genotype Observed BCT 4.4
T-Z- wt/tm 0.69
R-B- 0.47 0.45
B-Z- tm 0.00
W-A- sm 1.00
W-Z- 0.80 0.93
A-Z- sm 1.00
Y-Z- sm 1.00
T-W-Z- 0.83 0.85
B-W-A- sm 1.00
B-Y-Z- sm 1.00
W-A-Z- sm 1.00

 

Gutted mutants

Genotype Observed BCT 4.4
gutted 1.00 1.00
Y+(g) 1.00 1.00
Y++(g) 0.96 1.00
Y+++(g) 0.22 0.29
Y++++(g) 0.01 0.01
Zt 1.00 1.00
Y+Zt(g) 1.00 1.00
Y++Zt(g) 1.00 1.00
Y+++Zt(g) 1.00 0.97
Y++++Zt(g) 0.30 0.32
T+Y+(g) 0.98 1.00
A+Y+(g) 0.51 0.84
T+A+Y+(g) 0.72 0.93
W+A+Y+(g) 0.20 0.68
T+W+A+Y+(g) 0.00 0.00
T+Y+Zt(g) 0.99 1.00
A+Y+Zt(g) 0.88 1.00
T+A+Y+Zt(g) 0.96 1.00
W+A+Y+Zt(g) 0.93 1.00
T+W+A+Y+Zt(g) 0.10 0.00
T++Y++++(g) tm 0.01
W+Y+Zt(g) sm 1.00
T+W+Y+Zt(g) sm 1.00

 

Overproduction mutants

Genotype Observed BCT 4.4
T++ sm 1.00
R++ tm 0.00
B++ sm 1.00
W++ sm 1.00
A++ wt/sm 0.90
Y++ 0.19 0.00
Z++ sm 1.00
T++W++ wt 0.84
B+++Y++ sm 0.98
W++A++ sm 0.97
Y++++Z++++ 0.81 0.73

 

Mixed null/overproduction mutants

Genotype Observed BCT 4.4
T-B++ sm 1.00
T-Y++++ tm 0.87
T++Z- 0.46 0.00
B-W++ sm 1.00
B-Z++ sm 1.00
B++Z- sm 0.00
W++Z- sm 0.01
A++Z- tm 0.00
T-B+++Y++ sm 1.00
T-W++Z- wt/tm 0.69
T++W-Z- sm 0.95
R-B-W++ sm 1.00
R-B-Y++ 0.03 0.06

 

Predicted mutant phenotypes

Genotype Prediction
R-Z- sm
T-B-Z- tm
A++Y+(g) tm
R++Z++ sm
R++B++ wt
T++A++ tm
T++W++A++ wt/tm
Coordinate overexpression sm
T-A++Z- tm
W-A++Z- tm
T-W-A++Z- tm