Experiment: m.b. nitrite 8 mM
Only strains with sufficient reads to estimate fitness are shown,
but the strain fitness values are still rather noisy and may be biased towards zero.
Strains near the edge of a gene are not shown as being associated with that
gene (they are in grey).
Strains in the central 10-90% of a gene are color coded by the insertion's strand.
Usually, "+" means that the selectable marker is encoded on the forward strand,
i.e., transcribed rightward.
500 nt PGA1_c02290 and PGA1_c02300 overlap by 8 nucleotides PGA1_c02300 and PGA1_c02310 overlap by 4 nucleotides PGA1_c02310 and PGA1_c02320 are separated by 35 nucleotides
PGA1_c02290: PGA1_c02290 - putative NAD dependent epimerase/dehydratase, at 205,680 to 206,477
_c02290
PGA1_c02300: PGA1_c02300 - putative glycosyl transferase, at 206,470 to 207,246
_c02300
PGA1_c02310: PGA1_c02310 - putative pyridoxal-phosphate-dependent aminotransferase, at 207,243 to 208,439
_c02310
PGA1_c02320: PGA1_c02320 - GDP-mannose 4,6-dehydratase Gmd, at 208,475 to 209,608
_c02320
Position (kb)
207
208
209 Strain fitness (log2 ratio)
-4
-3
-2
-1
0
1
2
3 at 206.270 kb on + strand, within PGA1_c02290 at 206.270 kb on + strand, within PGA1_c02290 at 206.278 kb on - strand, within PGA1_c02290 at 206.278 kb on - strand, within PGA1_c02290 at 206.278 kb on - strand, within PGA1_c02290 at 206.278 kb on - strand, within PGA1_c02290 at 206.278 kb on - strand, within PGA1_c02290 at 206.278 kb on - strand, within PGA1_c02290 at 206.306 kb on + strand, within PGA1_c02290 at 206.319 kb on + strand, within PGA1_c02290 at 206.436 kb on - strand at 206.441 kb on - strand at 206.445 kb on - strand at 206.448 kb on + strand at 206.449 kb on + strand at 206.502 kb on + strand at 206.523 kb on + strand at 206.526 kb on - strand at 206.531 kb on - strand at 206.531 kb on - strand at 206.538 kb on - strand at 206.571 kb on + strand, within PGA1_c02300 at 206.575 kb on - strand, within PGA1_c02300 at 206.586 kb on + strand, within PGA1_c02300 at 206.586 kb on + strand, within PGA1_c02300 at 206.600 kb on + strand, within PGA1_c02300 at 206.603 kb on + strand, within PGA1_c02300 at 206.608 kb on - strand, within PGA1_c02300 at 206.608 kb on - strand, within PGA1_c02300 at 206.681 kb on + strand, within PGA1_c02300 at 206.710 kb on - strand, within PGA1_c02300 at 206.727 kb on + strand, within PGA1_c02300 at 206.729 kb on + strand, within PGA1_c02300 at 206.729 kb on + strand, within PGA1_c02300 at 206.771 kb on + strand, within PGA1_c02300 at 206.778 kb on + strand, within PGA1_c02300 at 206.802 kb on - strand, within PGA1_c02300 at 206.803 kb on - strand, within PGA1_c02300 at 206.803 kb on - strand, within PGA1_c02300 at 206.808 kb on - strand, within PGA1_c02300 at 206.810 kb on + strand, within PGA1_c02300 at 206.810 kb on + strand, within PGA1_c02300 at 206.818 kb on - strand, within PGA1_c02300 at 206.841 kb on + strand, within PGA1_c02300 at 206.844 kb on + strand, within PGA1_c02300 at 206.903 kb on - strand, within PGA1_c02300 at 206.913 kb on - strand, within PGA1_c02300 at 206.913 kb on - strand, within PGA1_c02300 at 206.928 kb on + strand, within PGA1_c02300 at 206.944 kb on + strand, within PGA1_c02300 at 206.947 kb on - strand, within PGA1_c02300 at 206.954 kb on + strand, within PGA1_c02300 at 206.987 kb on - strand, within PGA1_c02300 at 206.998 kb on + strand, within PGA1_c02300 at 206.998 kb on + strand, within PGA1_c02300 at 207.033 kb on - strand, within PGA1_c02300 at 207.065 kb on + strand, within PGA1_c02300 at 207.065 kb on + strand, within PGA1_c02300 at 207.073 kb on - strand, within PGA1_c02300 at 207.073 kb on - strand, within PGA1_c02300 at 207.073 kb on - strand, within PGA1_c02300 at 207.122 kb on - strand, within PGA1_c02300 at 207.179 kb on + strand at 207.187 kb on - strand at 207.187 kb on - strand at 207.200 kb on + strand at 207.208 kb on - strand at 207.231 kb on - strand at 207.243 kb on - strand at 207.274 kb on + strand at 207.274 kb on + strand at 207.282 kb on - strand at 207.282 kb on - strand at 207.304 kb on + strand at 207.355 kb on - strand at 207.398 kb on - strand, within PGA1_c02310 at 207.398 kb on - strand, within PGA1_c02310 at 207.408 kb on - strand, within PGA1_c02310 at 207.414 kb on + strand, within PGA1_c02310 at 207.425 kb on + strand, within PGA1_c02310 at 207.443 kb on + strand, within PGA1_c02310 at 207.494 kb on + strand, within PGA1_c02310 at 207.496 kb on - strand, within PGA1_c02310 at 207.518 kb on + strand, within PGA1_c02310 at 207.518 kb on + strand, within PGA1_c02310 at 207.518 kb on + strand, within PGA1_c02310 at 207.526 kb on - strand, within PGA1_c02310 at 207.571 kb on + strand, within PGA1_c02310 at 207.584 kb on - strand, within PGA1_c02310 at 207.607 kb on + strand, within PGA1_c02310 at 207.607 kb on + strand, within PGA1_c02310 at 207.607 kb on + strand, within PGA1_c02310 at 207.615 kb on - strand, within PGA1_c02310 at 207.615 kb on - strand, within PGA1_c02310 at 207.615 kb on - strand, within PGA1_c02310 at 207.617 kb on + strand, within PGA1_c02310 at 207.622 kb on + strand, within PGA1_c02310 at 207.626 kb on + strand, within PGA1_c02310 at 207.642 kb on + strand, within PGA1_c02310 at 207.642 kb on + strand, within PGA1_c02310 at 207.669 kb on - strand, within PGA1_c02310 at 207.688 kb on - strand, within PGA1_c02310 at 207.753 kb on - strand, within PGA1_c02310 at 207.755 kb on + strand, within PGA1_c02310 at 207.755 kb on + strand, within PGA1_c02310 at 207.763 kb on - strand, within PGA1_c02310 at 207.787 kb on + strand, within PGA1_c02310 at 207.848 kb on + strand, within PGA1_c02310 at 207.859 kb on - strand, within PGA1_c02310 at 207.870 kb on - strand, within PGA1_c02310 at 207.880 kb on - strand, within PGA1_c02310 at 207.898 kb on + strand, within PGA1_c02310 at 207.898 kb on + strand, within PGA1_c02310 at 207.906 kb on - strand, within PGA1_c02310 at 207.906 kb on - strand, within PGA1_c02310 at 207.906 kb on - strand, within PGA1_c02310 at 207.910 kb on + strand, within PGA1_c02310 at 207.918 kb on - strand, within PGA1_c02310 at 207.920 kb on + strand, within PGA1_c02310 at 207.923 kb on - strand, within PGA1_c02310 at 207.930 kb on - strand, within PGA1_c02310 at 207.942 kb on + strand, within PGA1_c02310 at 207.944 kb on - strand, within PGA1_c02310 at 207.949 kb on - strand, within PGA1_c02310 at 207.977 kb on + strand, within PGA1_c02310 at 207.977 kb on + strand, within PGA1_c02310 at 207.978 kb on + strand, within PGA1_c02310 at 207.978 kb on + strand, within PGA1_c02310 at 207.978 kb on + strand, within PGA1_c02310 at 207.978 kb on + strand, within PGA1_c02310 at 207.985 kb on - strand, within PGA1_c02310 at 207.986 kb on - strand, within PGA1_c02310 at 207.986 kb on - strand, within PGA1_c02310 at 207.986 kb on - strand, within PGA1_c02310 at 207.986 kb on - strand, within PGA1_c02310 at 208.038 kb on - strand, within PGA1_c02310 at 208.067 kb on + strand, within PGA1_c02310 at 208.110 kb on + strand, within PGA1_c02310 at 208.126 kb on + strand, within PGA1_c02310 at 208.126 kb on + strand, within PGA1_c02310 at 208.126 kb on + strand, within PGA1_c02310 at 208.126 kb on + strand, within PGA1_c02310 at 208.126 kb on + strand, within PGA1_c02310 at 208.126 kb on + strand, within PGA1_c02310 at 208.146 kb on + strand, within PGA1_c02310 at 208.146 kb on + strand, within PGA1_c02310 at 208.154 kb on - strand, within PGA1_c02310 at 208.159 kb on + strand, within PGA1_c02310 at 208.159 kb on - strand, within PGA1_c02310 at 208.159 kb on - strand, within PGA1_c02310 at 208.167 kb on - strand, within PGA1_c02310 at 208.172 kb on - strand, within PGA1_c02310 at 208.172 kb on - strand, within PGA1_c02310 at 208.179 kb on - strand, within PGA1_c02310 at 208.198 kb on + strand, within PGA1_c02310 at 208.208 kb on + strand, within PGA1_c02310 at 208.208 kb on + strand, within PGA1_c02310 at 208.208 kb on + strand, within PGA1_c02310 at 208.208 kb on + strand, within PGA1_c02310 at 208.208 kb on + strand, within PGA1_c02310 at 208.216 kb on - strand, within PGA1_c02310 at 208.216 kb on - strand, within PGA1_c02310 at 208.216 kb on - strand, within PGA1_c02310 at 208.223 kb on + strand, within PGA1_c02310 at 208.231 kb on - strand, within PGA1_c02310 at 208.275 kb on + strand, within PGA1_c02310 at 208.291 kb on - strand, within PGA1_c02310 at 208.306 kb on + strand, within PGA1_c02310 at 208.306 kb on + strand, within PGA1_c02310 at 208.306 kb on + strand, within PGA1_c02310 at 208.311 kb on + strand, within PGA1_c02310 at 208.311 kb on + strand, within PGA1_c02310 at 208.317 kb on + strand, within PGA1_c02310 at 208.352 kb on - strand at 208.363 kb on - strand at 208.391 kb on + strand at 208.391 kb on + strand at 208.398 kb on + strand at 208.409 kb on + strand at 208.409 kb on + strand at 208.409 kb on + strand at 208.409 kb on + strand at 208.409 kb on + strand at 208.409 kb on + strand at 208.409 kb on + strand at 208.409 kb on + strand at 208.409 kb on + strand at 208.409 kb on + strand at 208.409 kb on + strand at 208.409 kb on + strand at 208.417 kb on - strand at 208.417 kb on - strand at 208.417 kb on - strand at 208.441 kb on - strand at 208.443 kb on + strand at 208.443 kb on - strand at 208.528 kb on - strand at 208.689 kb on + strand, within PGA1_c02320 at 208.689 kb on + strand, within PGA1_c02320 at 208.689 kb on + strand, within PGA1_c02320 at 208.689 kb on + strand, within PGA1_c02320 at 208.689 kb on + strand, within PGA1_c02320 at 208.733 kb on + strand, within PGA1_c02320 at 208.741 kb on - strand, within PGA1_c02320 at 208.748 kb on + strand, within PGA1_c02320 at 208.874 kb on - strand, within PGA1_c02320 at 208.876 kb on + strand, within PGA1_c02320 at 208.921 kb on + strand, within PGA1_c02320 at 208.951 kb on + strand, within PGA1_c02320 at 208.951 kb on + strand, within PGA1_c02320 at 208.969 kb on + strand, within PGA1_c02320 at 208.969 kb on + strand, within PGA1_c02320 at 208.969 kb on + strand, within PGA1_c02320 at 208.977 kb on - strand, within PGA1_c02320 at 208.977 kb on - strand, within PGA1_c02320 at 208.977 kb on - strand, within PGA1_c02320 at 208.977 kb on - strand, within PGA1_c02320 at 208.991 kb on - strand, within PGA1_c02320 at 209.001 kb on - strand, within PGA1_c02320 at 209.001 kb on - strand, within PGA1_c02320 at 209.005 kb on + strand, within PGA1_c02320 at 209.006 kb on + strand, within PGA1_c02320 at 209.013 kb on - strand, within PGA1_c02320 at 209.023 kb on - strand, within PGA1_c02320 at 209.044 kb on + strand, within PGA1_c02320 at 209.126 kb on - strand, within PGA1_c02320 at 209.128 kb on - strand, within PGA1_c02320 at 209.136 kb on - strand, within PGA1_c02320 at 209.141 kb on + strand, within PGA1_c02320 at 209.187 kb on - strand, within PGA1_c02320 at 209.204 kb on + strand, within PGA1_c02320 at 209.285 kb on + strand, within PGA1_c02320 at 209.383 kb on + strand, within PGA1_c02320 at 209.403 kb on + strand, within PGA1_c02320 at 209.406 kb on - strand, within PGA1_c02320
Per-strain Table
Position Strand Gene LocusTag Fraction m.b. nitrite 8 mM remove 206,270 + PGA1_c02290 0.74 -2.3 206,270 + PGA1_c02290 0.74 +0.4 206,278 - PGA1_c02290 0.75 -0.1 206,278 - PGA1_c02290 0.75 +0.6 206,278 - PGA1_c02290 0.75 +2.3 206,278 - PGA1_c02290 0.75 +1.3 206,278 - PGA1_c02290 0.75 -1.2 206,278 - PGA1_c02290 0.75 +0.4 206,306 + PGA1_c02290 0.78 +0.3 206,319 + PGA1_c02290 0.80 +0.0 206,436 - +1.3 206,441 - -1.1 206,445 - -1.1 206,448 + -0.6 206,449 + +0.2 206,502 + -0.3 206,523 + +1.3 206,526 - -2.2 206,531 - -0.2 206,531 - +0.4 206,538 - -2.1 206,571 + PGA1_c02300 0.13 -0.2 206,575 - PGA1_c02300 0.14 +1.5 206,586 + PGA1_c02300 0.15 +0.7 206,586 + PGA1_c02300 0.15 +2.8 206,600 + PGA1_c02300 0.17 -1.8 206,603 + PGA1_c02300 0.17 -0.8 206,608 - PGA1_c02300 0.18 -2.3 206,608 - PGA1_c02300 0.18 +2.5 206,681 + PGA1_c02300 0.27 -0.8 206,710 - PGA1_c02300 0.31 -0.2 206,727 + PGA1_c02300 0.33 -2.5 206,729 + PGA1_c02300 0.33 +2.1 206,729 + PGA1_c02300 0.33 -0.3 206,771 + PGA1_c02300 0.39 -0.5 206,778 + PGA1_c02300 0.40 +0.6 206,802 - PGA1_c02300 0.43 +2.8 206,803 - PGA1_c02300 0.43 +1.0 206,803 - PGA1_c02300 0.43 -0.6 206,808 - PGA1_c02300 0.44 -0.6 206,810 + PGA1_c02300 0.44 -0.4 206,810 + PGA1_c02300 0.44 -1.0 206,818 - PGA1_c02300 0.45 +0.1 206,841 + PGA1_c02300 0.48 +0.4 206,844 + PGA1_c02300 0.48 +1.2 206,903 - PGA1_c02300 0.56 -1.6 206,913 - PGA1_c02300 0.57 +0.4 206,913 - PGA1_c02300 0.57 +1.5 206,928 + PGA1_c02300 0.59 -0.5 206,944 + PGA1_c02300 0.61 -0.2 206,947 - PGA1_c02300 0.61 +0.8 206,954 + PGA1_c02300 0.62 +0.1 206,987 - PGA1_c02300 0.67 -2.4 206,998 + PGA1_c02300 0.68 -0.1 206,998 + PGA1_c02300 0.68 +0.5 207,033 - PGA1_c02300 0.72 -0.6 207,065 + PGA1_c02300 0.77 +0.6 207,065 + PGA1_c02300 0.77 +0.0 207,073 - PGA1_c02300 0.78 -1.8 207,073 - PGA1_c02300 0.78 -0.5 207,073 - PGA1_c02300 0.78 -2.1 207,122 - PGA1_c02300 0.84 +0.8 207,179 + -0.9 207,187 - +0.5 207,187 - -1.8 207,200 + +0.9 207,208 - -0.1 207,231 - -0.6 207,243 - +0.2 207,274 + +0.2 207,274 + -2.3 207,282 - -2.2 207,282 - +1.5 207,304 + -2.0 207,355 - -0.0 207,398 - PGA1_c02310 0.13 -0.8 207,398 - PGA1_c02310 0.13 +1.1 207,408 - PGA1_c02310 0.14 -3.9 207,414 + PGA1_c02310 0.14 +0.5 207,425 + PGA1_c02310 0.15 -0.5 207,443 + PGA1_c02310 0.17 +0.3 207,494 + PGA1_c02310 0.21 -1.4 207,496 - PGA1_c02310 0.21 -1.7 207,518 + PGA1_c02310 0.23 -2.4 207,518 + PGA1_c02310 0.23 -2.1 207,518 + PGA1_c02310 0.23 -2.5 207,526 - PGA1_c02310 0.24 +1.8 207,571 + PGA1_c02310 0.27 -1.8 207,584 - PGA1_c02310 0.28 -0.1 207,607 + PGA1_c02310 0.30 -0.4 207,607 + PGA1_c02310 0.30 -1.1 207,607 + PGA1_c02310 0.30 -1.8 207,615 - PGA1_c02310 0.31 -0.6 207,615 - PGA1_c02310 0.31 +0.7 207,615 - PGA1_c02310 0.31 -2.7 207,617 + PGA1_c02310 0.31 -0.2 207,622 + PGA1_c02310 0.32 -1.6 207,626 + PGA1_c02310 0.32 -0.7 207,642 + PGA1_c02310 0.33 -2.5 207,642 + PGA1_c02310 0.33 -1.4 207,669 - PGA1_c02310 0.36 -1.9 207,688 - PGA1_c02310 0.37 +0.4 207,753 - PGA1_c02310 0.43 +1.5 207,755 + PGA1_c02310 0.43 -1.4 207,755 + PGA1_c02310 0.43 +1.4 207,763 - PGA1_c02310 0.43 -2.6 207,787 + PGA1_c02310 0.45 -2.7 207,848 + PGA1_c02310 0.51 -0.4 207,859 - PGA1_c02310 0.51 -0.2 207,870 - PGA1_c02310 0.52 +0.5 207,880 - PGA1_c02310 0.53 +0.3 207,898 + PGA1_c02310 0.55 -1.2 207,898 + PGA1_c02310 0.55 -0.4 207,906 - PGA1_c02310 0.55 -3.7 207,906 - PGA1_c02310 0.55 +1.6 207,906 - PGA1_c02310 0.55 +0.3 207,910 + PGA1_c02310 0.56 -1.1 207,918 - PGA1_c02310 0.56 -1.2 207,920 + PGA1_c02310 0.57 -1.6 207,923 - PGA1_c02310 0.57 +0.5 207,930 - PGA1_c02310 0.57 -1.7 207,942 + PGA1_c02310 0.58 -1.8 207,944 - PGA1_c02310 0.59 +0.6 207,949 - PGA1_c02310 0.59 -0.2 207,977 + PGA1_c02310 0.61 -0.1 207,977 + PGA1_c02310 0.61 +1.3 207,978 + PGA1_c02310 0.61 -0.2 207,978 + PGA1_c02310 0.61 -1.8 207,978 + PGA1_c02310 0.61 -2.3 207,978 + PGA1_c02310 0.61 +0.4 207,985 - PGA1_c02310 0.62 -0.4 207,986 - PGA1_c02310 0.62 -2.2 207,986 - PGA1_c02310 0.62 -1.2 207,986 - PGA1_c02310 0.62 +1.8 207,986 - PGA1_c02310 0.62 -1.0 208,038 - PGA1_c02310 0.66 -1.4 208,067 + PGA1_c02310 0.69 +0.8 208,110 + PGA1_c02310 0.72 +0.2 208,126 + PGA1_c02310 0.74 +0.4 208,126 + PGA1_c02310 0.74 +0.3 208,126 + PGA1_c02310 0.74 +0.9 208,126 + PGA1_c02310 0.74 +0.4 208,126 + PGA1_c02310 0.74 -0.8 208,126 + PGA1_c02310 0.74 -1.6 208,146 + PGA1_c02310 0.75 +0.8 208,146 + PGA1_c02310 0.75 -0.6 208,154 - PGA1_c02310 0.76 -2.3 208,159 + PGA1_c02310 0.77 +0.5 208,159 - PGA1_c02310 0.77 +1.5 208,159 - PGA1_c02310 0.77 +0.7 208,167 - PGA1_c02310 0.77 -1.4 208,172 - PGA1_c02310 0.78 -0.2 208,172 - PGA1_c02310 0.78 -2.1 208,179 - PGA1_c02310 0.78 -2.2 208,198 + PGA1_c02310 0.80 -0.2 208,208 + PGA1_c02310 0.81 -2.1 208,208 + PGA1_c02310 0.81 -1.4 208,208 + PGA1_c02310 0.81 -0.2 208,208 + PGA1_c02310 0.81 +0.1 208,208 + PGA1_c02310 0.81 -2.1 208,216 - PGA1_c02310 0.81 +2.1 208,216 - PGA1_c02310 0.81 -1.8 208,216 - PGA1_c02310 0.81 +0.9 208,223 + PGA1_c02310 0.82 +1.6 208,231 - PGA1_c02310 0.83 -1.6 208,275 + PGA1_c02310 0.86 +0.2 208,291 - PGA1_c02310 0.88 -0.1 208,306 + PGA1_c02310 0.89 -2.3 208,306 + PGA1_c02310 0.89 +2.8 208,306 + PGA1_c02310 0.89 -0.7 208,311 + PGA1_c02310 0.89 -1.6 208,311 + PGA1_c02310 0.89 +0.8 208,317 + PGA1_c02310 0.90 +1.4 208,352 - +2.6 208,363 - +0.3 208,391 + -1.7 208,391 + -2.3 208,398 + +0.3 208,409 + +1.6 208,409 + -0.0 208,409 + -1.6 208,409 + -3.2 208,409 + +0.5 208,409 + -1.6 208,409 + -2.6 208,409 + -1.9 208,409 + +0.5 208,409 + +0.4 208,409 + +0.9 208,409 + +1.0 208,417 - +1.1 208,417 - +1.3 208,417 - +0.1 208,441 - +1.5 208,443 + -0.6 208,443 - +2.3 208,528 - -1.6 208,689 + PGA1_c02320 0.19 -0.7 208,689 + PGA1_c02320 0.19 -2.6 208,689 + PGA1_c02320 0.19 +0.3 208,689 + PGA1_c02320 0.19 +1.8 208,689 + PGA1_c02320 0.19 +0.0 208,733 + PGA1_c02320 0.23 -1.2 208,741 - PGA1_c02320 0.23 -1.8 208,748 + PGA1_c02320 0.24 +0.7 208,874 - PGA1_c02320 0.35 +1.8 208,876 + PGA1_c02320 0.35 -1.6 208,921 + PGA1_c02320 0.39 +0.1 208,951 + PGA1_c02320 0.42 -0.2 208,951 + PGA1_c02320 0.42 +1.8 208,969 + PGA1_c02320 0.44 +0.4 208,969 + PGA1_c02320 0.44 -0.4 208,969 + PGA1_c02320 0.44 +0.2 208,977 - PGA1_c02320 0.44 +0.2 208,977 - PGA1_c02320 0.44 +0.2 208,977 - PGA1_c02320 0.44 +0.1 208,977 - PGA1_c02320 0.44 -0.6 208,991 - PGA1_c02320 0.46 -1.0 209,001 - PGA1_c02320 0.46 +0.2 209,001 - PGA1_c02320 0.46 +0.2 209,005 + PGA1_c02320 0.47 -0.2 209,006 + PGA1_c02320 0.47 +0.0 209,013 - PGA1_c02320 0.47 -1.6 209,023 - PGA1_c02320 0.48 +0.0 209,044 + PGA1_c02320 0.50 +1.1 209,126 - PGA1_c02320 0.57 +1.2 209,128 - PGA1_c02320 0.58 +1.8 209,136 - PGA1_c02320 0.58 -1.9 209,141 + PGA1_c02320 0.59 -2.5 209,187 - PGA1_c02320 0.63 +1.1 209,204 + PGA1_c02320 0.64 -2.3 209,285 + PGA1_c02320 0.71 -1.2 209,383 + PGA1_c02320 0.80 -0.1 209,403 + PGA1_c02320 0.82 -0.1 209,406 - PGA1_c02320 0.82 -3.7
Or see this region's nucleotide sequence