Table 1

Models describing the distributions of clonal susceptibility for the pre-epidemic, post-epidemic and post-sex clones.

Type of selection

Model

Pre-epidemic

Post-epidemic

Post-sex

n

AIC

evidence ratio


No selection

1) unimodal: null

μA

σA

μA

σA

μA

σA

2

-45.29

2145

2) bimodal: null

μ1A

σA

μ2A

σA

μ1A

σA

μ2A

σA

μ1A

σA

μ2A

σA

3

-51.61

90.8

Directional selection

3*) unimodal: mean, var differ

μA

σA

μB

σB

μC

σC

6

-44.74

2817

4) unimodal: pre-epidemic differs

μA

σA

μB

σB

μB

σB

4

-47.99

557

5*) bimodal: all modes differ

μ1A

σA

μ2A

σA

μ1B

σA

μ2B

σA

μ1C

σA

μ2C

σA

7

-56.96

6.27

6) bimodal: pre-epidemic differs

μ1A

σA

μ2A

σA

μ1B

σA

μ2B

σA

μ1B

σA

μ2B

σA

5

-60.55

1.04

Disruptive selection

7) mixed: uni-bi.-bi., same modes

μA

σA

μ1B

σA

μ2B

σA

μ1B

σA

μ2B

σA

4

-60.63

1

8*) mixed: uni.-bi.-bi., modes differ

μA

σA

μ1B

σA

μ2B

σA

μ1C

σA

μ2C

σA

6

-56.86

6.58

9*) mixed: uni.-bi.-uni.

μA

σA

μ1B

σB

μ2B

σB

μC

σC

7

-52.02

74


The mean/mode parameter of the unimodal normal distribution is μ and the standard deviation is σ. The central tendency parameters for the modes in the bimodal normal distributions are μ1 and μ2 and the standard deviation for each mode is σi. Within each model, parameters with the same subscript are constrained to be equal. Parameters for the best fit model (model 7, highlighted in bold) with 95% confidence intervals based on likelihood profile [51] in parentheses are μA = 0.28 (0.24–0.32), μ1B = 0.42 (0.38–0.46), μ2B = 0.10 (0.06–0.15), σA = 0.08 (0.07–0.11). Parameters for model 6 are μ1A = 0.21 (0.11–0.40), μ2A = 0.34 (0.11–0.40), μ1B = 0.42 (0.38–0.45), μ2B = 0.10 (0.06–0.14), σA = 0.07 (0.06–0.10). Model selection is based on Akaike's Information Criteria (AIC) which incorporates the number of estimated parameters (n). "Uni" = unimodal; "bi" = bimodal. The evidence ratio is the odds ratio of support for the best fit model over the listed model [50]; models with evidence ratios close to 1 are well-supported. Models that allow for a change in the distribution after sexual reproduction have an asterisk (*) after the model number.

Duffy et al. BMC Evolutionary Biology 2008 8:80   doi:10.1186/1471-2148-8-80

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