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Table 1 Testing the hypothesis that GC% values sampled from 20-kb windows follow a binomial distribution

From: Isochores Merit the Prefix 'Iso'

seq

# win (n)

mean

var σ2

binomial var

σ2/

c2 = (n - 1) σ2/

p-value

MHC class III

32

0.5188

0.0005345

0.00001248

42.8215

1327.47

0

MHC class II

45

0.4105

0.0007268

0.00001210

60.0709

2703.19

0

random (class III)

32

0.5185

0.00001137

0.00001248

0.9110

28.2402

0.609

random (class II)

45

0.4106

0.00001255

0.00001210

1.0369

45.6244

0.404

B. burgdorferi

45

0.2859

0.0001515

0.00001021

14.8432

653.099

0

  1. Five sequences are tested: MHC class III and MHC class II isochore sequences, two random sequences similar these two MHC sequences (same length and same base composition), and bacterium Borrelia burgdorferi genome sequence. Detailed explanation of column headers: 1. Sequence name. 2. Total number of windows in the sequence (n), with each contributing a GC% value. 3. Mean of the GC% (m). 4. Variance of the GC% (σ2). 5. Variance of GC% expected from a binomial distribution ( = m(1 - m)/20000). 6. Ratio of the two variances σ2/ 7. test statistic c2 = (n - 1) σ2/. 8. p-value from the binomial distribution test.