Table 1 Data summary. The relative fitness, number of fitness determinations, epistasis coefficient, and the Hamming distance to the WT folding obtained with the RNAdistance program are shown for each genotype. Errors represent ±1 SEM

WT

1.000 ± 0.006

15

A16G

0.918 ± 0.033

24

66

C18A

0.958 ± 0.042

12

0

C23G

0.962 ± 0.029

21

16

A24U

0.878 ± 0.057

21

0

A37G

0.861 ± 0.032

15

32

G39U

0.915 ± 0.033

30

0

A46U

0.910 ± 0.042

21

8

A54G

0.823 ± 0.058

21

49

C57U

0.808 ± 0.052

15

4

G75U

0.802 ± 0.061

18

47

A83G

0.927 ± 0.055

10

53

A84G

0.866 ± 0.037

35

10

C91U

0.913 ± 0.033

32

0

C100G

0

30

48

C106U

0.896 ± 0.051

24

37

C127U

0

30

53

U131C

0.997 ± 0.023

15

0

A135G

0.971 ± 0.033

27

7

G138U

0.985 ± 0.023

24

2

G142A

0.873 ± 0.038

27

32

A16G/C23G

0.999 ± 0.024

24

0.117 ± 0.089

40

A16G/C100G

0.902 ± 0.042

27

0.903 ± 0.048

33

A16G/C127U

0

30

0

53

A16G/A135G

1.012 ± 0.020

21

0.120 ± 0.089

7

C18A/C100G

0

30

0

48

C23G/A24U

0.932 ± 0.034

21

0.088 ± 0.120

10

C23G/A54G

1.040 ± 0.005

3

0.250 ± 0.091

57

C23G/142A

0

30

−0.839 ± 0.062

40

A24U/C106U

1.031 ± 0.056

21

0.244 ± 0.159

37

A37G/C106U

0.899 ± 0.024

21

0.127 ± 0.102

18

A37G/A135G

0.956 ± 0.004

30

0.120 ± 0.070

7

G39U/C91U

0.901 ± 0.032

27

0.066 ± 0.098

0

A46U/A135G

0.900 ± 0.013

32

0.017 ± 0.090

15

C57U/G75U

0.906 ± 0.039

30

0.259 ± 0.135

8

C57U/A83G

0.823 ± 0.052

9

0.074 ± 0.150

45

C57U/C127U

0.949 ± 0.037

27

0.949 ± 0.043

35

A83G/C100G

1.019 ± 0.019

18

1.019 ± 0.026

53

A84G/G142A

0.999 ± 0.014

24

0.244 ± 0.086

32

C91U/U131C

1.016 ± 0.015

30

0.106 ± 0.075

0

C91U/A135G

0.833 ± 0.007

3

−0.053 ± 0.074

7

C100G/C106U

0.751 ± 0.035

11

0.751 ± 0.040

48

C100G/G138U

0.635 ± 0.002

3

0.635 ± 0.006

33

C127U/A135G

0.816 ± 0.077

6

0.817 ± 0.082

7

U131C/G142A

0.705 ± 0.048

6

−0.166 ± 0.111

20

A135G/G138U

0

10

−0.957 ± 0.055

9