Introduction |
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xv | |
Part 1 Network Motifs |
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Chapter 1 Transcription Networks: Basic Concepts |
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3 | (18) |
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3 | (1) |
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1.2 The Cognitive Problem of the Cell |
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3 | (2) |
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1.3 Elements of Transcription Networks |
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5 | (8) |
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1.3.1 Separation of Timescales |
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7 | (1) |
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1.3.2 The Signs on the Arrows: Activators and Repressors |
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8 | (1) |
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1.3.3 The Numbers on the Arrows: Input Functions |
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9 | (1) |
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1.3.4 Logic Input Functions: A Simple Framework for Understanding Network Dynamics |
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10 | (1) |
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1.3.5 Multi-Dimensional Input Functions Govern Genes with Several Inputs |
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11 | (2) |
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1.4 Dynamics and Response Time of Simple Regulation |
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13 | (2) |
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1.4.1 The Response Time of Stable Proteins Is One Cell Generation |
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15 | (1) |
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15 | (1) |
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16 | (2) |
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18 | (3) |
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Chapter 2 Autoregulation: A Network Motif |
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21 | (16) |
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21 | (1) |
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2.2 Patterns, Randomized Networks and Network Motifs |
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21 | (2) |
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2.2.1 Detecting Network Motifs by Comparison to Randomized Networks |
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23 | (1) |
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2.3 Autoregulation Is a Network Motif |
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23 | (1) |
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2.4 Negative Autoregulation Speeds the Response Time of Gene Circuits |
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24 | (5) |
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2.4.1 Rate Analysis Shows Speedup for Any Repressive Input Function f(X) |
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28 | (1) |
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2.5 Negative Autoregulation Promotes Robustness to Fluctuations in Production Rate |
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29 | (1) |
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2.6 Summary: Evolution as an Engineer |
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30 | (1) |
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31 | (1) |
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31 | (5) |
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36 | (1) |
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Chapter 3 The Feedforward Loop Network Motif |
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37 | (24) |
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37 | (1) |
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3.2 The Feedforward Loop Is a Network Motif |
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37 | (2) |
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3.3 The Structure of the Feedforward Loop Gene Circuit |
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39 | (2) |
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3.4 Dynamics of the Coherent Type-1 FFL with AND Logic |
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41 | (1) |
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3.5 The C1-FFL Is a Sign-Sensitive Delay Element |
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42 | (4) |
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3.5.1 Delay Following an ON Step of Sx |
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43 | (1) |
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3.5.2 No Delay Following an OFF Step of Sx |
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44 | (1) |
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3.5.3 The C1-FFL Is a Sign-Sensitive Delay Element |
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44 | (1) |
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3.5.4 Sign-Sensitive Delay Can Protect against Brief Input Fluctuations |
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44 | (1) |
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3.5.5 Sign-Sensitive Delay in the Arabinose System of E. coil |
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45 | (1) |
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3.6 OR-Gate C1-FFL Is a Sign-Sensitive Delay for OFF Steps |
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46 | (1) |
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3.7 The Incoherent Type-1 FFL Generates Pulses of Output |
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47 | (4) |
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3.7.1 The Incoherent FFL Can Speed Response Times |
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48 | (1) |
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3.7.2 Interim Summary: Three Ways to Speed Your Response Time |
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49 | (1) |
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3.7.3 The I1-FFL Can Provide Biphasic Steady-State Response Curves |
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50 | (1) |
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3.8 The Other Six FFL Types Can Also Act as Filters and Pulse Generators |
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51 | (1) |
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3.9 Convergent Evolution of FFLs |
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51 | (1) |
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52 | (1) |
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52 | (1) |
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53 | (6) |
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59 | (2) |
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Chapter 4 Temporal Programs and the Global Structure of Transcription Networks |
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61 | (16) |
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61 | (1) |
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4.2 The Single-Input Module (SIM) Network Motif |
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61 | (1) |
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4.3 The SIM Can Generate Temporal Gene Expression Programs |
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62 | (2) |
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4.4 The Multi-Output Feedforward Loop |
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64 | (2) |
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4.5 The Multi-Output FFL Can Generate FIFO Temporal Programs |
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66 | (2) |
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4.5.1 The Multi-Output FFL Also Acts as a Persistence Detector for Each Output |
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68 | (1) |
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4.6 Signal Integration by Bi-Fans and Dense-Overlapping Regulons |
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68 | (2) |
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4.7 Network Motifs and the Global Structure of Sensory Transcription Networks |
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70 | (1) |
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4.8 Interlocked Feedforward Loops in the B. subtilis Sporulation Network |
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70 | (3) |
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73 | (1) |
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73 | (2) |
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75 | (2) |
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Chapter 5 Positive Feedback, Bistability and Memory |
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77 | (20) |
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5.1 Network Motifs in Developmental Transcription Networks |
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77 | (8) |
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5.1.1 Positive Autoregulation Slows Responses and Can Lead to Bistability |
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78 | (2) |
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5.1.2 Two-Node Positive Feedback Loops for Decision-Making |
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80 | (3) |
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5.1.3 Regulating Feedback and Regulated Feedback |
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83 | (1) |
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5.1.4 Long Transcription Cascades and Developmental Timing |
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84 | (1) |
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5.2 Network Motifs in Protein-Protein Interaction Networks |
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85 | (3) |
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5.2.1 Hybrid Network Motifs Include a Two-Node Negative Feedback Loop |
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85 | (2) |
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5.2.2 Hybrid FFL Motifs Can Provide Transient Memory |
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87 | (1) |
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5.2.3 Feedforward Loops Show a Milder Version of the Functions of Feedback Loops |
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87 | (1) |
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5.3 Network Motifs in Neuronal Networks |
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88 | (3) |
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5.3.1 Multi-Input FFLs in Neuronal Networks |
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89 | (2) |
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91 | (1) |
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91 | (1) |
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92 | (2) |
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94 | (3) |
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Chapter 6 How to Build a Biological Oscillator |
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97 | (20) |
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6.1 Oscillations Require Negative Feedback and Delay |
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97 | (4) |
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6.1.1 In Order to Oscillate, You Need to Add a Sizable Delay to the Negative Feedback Loop |
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97 | (4) |
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6.2 Noise Can Induce Oscillations in Systems That Have Only Damped Oscillations on Paper |
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101 | (1) |
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102 | (1) |
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6.4 Many Biological Oscillators Have a Coupled Positive and Negative Feedback Loop Motif |
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103 | (4) |
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6.5 Robust Bistability Using Two Positive Feedback Loops |
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107 | (3) |
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110 | (1) |
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110 | (2) |
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112 | (5) |
Part 2 Robustness |
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Chapter 7 Kinetic Proofreading and Conformational Proofreading |
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117 | (20) |
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117 | (1) |
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7.2 Kinetic Proofreading of the Genetic Code Can Reduce Error Rates |
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118 | (5) |
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7.2.1 Equilibrium Binding Cannot Explain the Precision of Translation |
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119 | (2) |
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7.2.2 Kinetic Proofreading Can Dramatically Reduce the Error Rate |
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121 | (2) |
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7.3 Recognition of Self and Non-Self by the Immune System |
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123 | (4) |
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7.3.1 Equilibrium Binding Cannot Explain the Low Error Rate of Immune Recognition |
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124 | (1) |
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7.3.2 Kinetic Proofreading Increases Fidelity of T-Cell Recognition |
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125 | (2) |
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7.4 Kinetic Proofreading Occurs in Diverse Processes in the Cell |
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127 | (1) |
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7.5 Conformational Proofreading Provides Specificity without Consuming Energy |
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128 | (1) |
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7.6 Demand Rules for Gene Regulation Can Minimize Errors |
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129 | (1) |
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130 | (1) |
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131 | (5) |
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136 | (1) |
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Chapter 8 Robust Signaling by Bifunctional Components |
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137 | (16) |
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8.1 Robust Input-Output Curves |
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137 | (1) |
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8.2 Simple Signaling Circuits Are Not Robust |
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138 | (2) |
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8.3 Bacterial Two-Component Systems Can Achieve Robustness |
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140 | (4) |
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8.3.1 Limits of Robustness |
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143 | (1) |
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8.3.2 Remarks on the Black-Box Approach |
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143 | (1) |
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8.3.3 Bifunctional Components Provide Robustness in Diverse Circuits |
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144 | (1) |
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144 | (1) |
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145 | (5) |
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150 | (3) |
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Chapter 9 Robustness in Bacterial Chemotaxis |
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153 | (22) |
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153 | (1) |
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9.2 Bacterial Chemotaxis, or How Bacteria Think |
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153 | (3) |
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9.2.1 Chemotaxis Behavior |
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153 | (2) |
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9.2.2 Response and Exact Adaptation |
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155 | (1) |
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9.3 The Chemotaxis Protein Circuit |
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156 | (3) |
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9.3.1 Attractants Lower the Activity of X |
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157 | (1) |
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9.3.2 Adaptation Is Due to Slow Modification of X That Increases Its Activity |
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158 | (1) |
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9.4 The Barkai-Leibler Model of Exact Adaptation |
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159 | (6) |
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9.4.1 Robust Adaptation and Integral Feedback |
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162 | (2) |
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9.4.2 Experiments Show That Exact Adaptation Is Robust, Whereas Steady-State Activity and Adaptation Times Are Fine-Tuned |
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164 | (1) |
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9.5 Individuality and Robustness in Bacterial Chemotaxis |
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165 | (1) |
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166 | (1) |
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166 | (6) |
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172 | (3) |
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Chapter 10 Fold-Change Detection |
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175 | (16) |
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10.1 Universal Features of Sensory Systems |
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175 | (1) |
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10.2 Fold-Change Detection in Bacterial Chemotaxis |
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176 | (4) |
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10.2.1 Definition of Fold-Change Detection (FCD) |
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177 | (1) |
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10.2.2 The Chemotaxis Circuit Provides FCD by Means of a Nonlinear Integral-Feedback Loop |
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178 | (2) |
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10.3 FCD and Exact Adaptation |
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180 | (1) |
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10.4 The Incoherent Feedforward Loop Can Show FCD |
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180 | (2) |
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10.5 A General Condition for FCD |
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182 | (1) |
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10.6 Identifying FCD Circuits from Dynamic Measurements |
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183 | (1) |
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10.7 FCD Provides Robustness to Input Noise and Allows Scale- Invariant Searches |
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184 | (2) |
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186 | (1) |
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186 | (2) |
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188 | (3) |
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Chapter 11 Dynamical Compensation and Mutant Resistance in Tissues |
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191 | (18) |
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11.1 The Insulin-Glucose Feedback Loop |
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191 | (2) |
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11.2 The Minimal Model Is Not Robust to Changes in Insulin Sensitivity |
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193 | (1) |
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11.3 A Slow Feedback Loop on Beta-Cell Numbers Provides Compensation |
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194 | (3) |
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11.4 Dynamical Compensation Allows the Circuit to Buffer Parameter Variations |
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197 | (3) |
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11.5 Type 2 Diabetes Is Linked with Instability Due to a U-Shaped Death Curve |
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200 | (1) |
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11.6 Tissue-Level Feedback Loops Are Fragile to Invasion by Mutants That Misread the Signal |
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201 | (1) |
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11.7 Biphasic (U-Shaped) Response Curves Can Protect against Mutant Takeover |
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202 | (1) |
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203 | (1) |
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204 | (1) |
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204 | (3) |
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207 | (2) |
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Chapter 12 Robust Spatial Patterning in Development |
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209 | (18) |
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12.1 The French Flag Model Is Not Robust |
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210 | (2) |
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12.2 Increased Robustness by Self-Enhanced Morphogen Degradation |
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212 | (2) |
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12.3 Network Motifs That Provide Degradation Feedback for Robust Patterning |
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214 | (1) |
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12.4 The Robustness Principle Can Distinguish between Mechanisms of Fruit Fly Patterning |
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215 | (5) |
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220 | (1) |
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220 | (3) |
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223 | (4) |
Part 3 Optimality |
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Chapter 13 Optimal Gene Circuit Design |
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227 | (22) |
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227 | (1) |
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13.2 Optimal Expression Level of a Protein under Constant Conditions |
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228 | (6) |
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13.2.1 Cost of the LacZ Protein |
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229 | (1) |
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13.2.2 The Benefit of the LacZ Protein |
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230 | (1) |
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13.2.3 Fitness Function and the Optimal Expression Level |
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231 | (1) |
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13.2.4 Cells Reach Optimal LacZ Levels in a Few Hundred Generations in Laboratory Evolution Experiments |
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232 | (2) |
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13.3 To Regulate or Not to Regulate? Optimal Regulation in Changing Environments |
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234 | (2) |
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13.4 Environmental Selection of the Feedforward Loop Network Motif |
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236 | (2) |
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238 | (1) |
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239 | (1) |
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239 | (8) |
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247 | (2) |
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Chapter 14 Multi-Objective Optimality in Biology |
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249 | (24) |
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249 | (1) |
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14.2 The Fitness Landscape Picture for a Single Task |
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249 | (1) |
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14.3 Multiple Tasks Are Characterized by Performance Functions |
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250 | (1) |
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14.4 Pareto Optimality in Performance Space |
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251 | (1) |
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14.5 Pareto Optimality in Trait Space Leads to Simple Patterns |
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252 | (1) |
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14.6 Two Tasks Lead to a Line Segment, Three Tasks to a Triangle, Four to a Tetrahedron |
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253 | (1) |
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14.7 Trade-Offs in Morphology |
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254 | (2) |
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14.8 Archetypes Can Last over Geological Timescales |
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256 | (1) |
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14.9 Trade-Offs for Proteins |
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257 | (1) |
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14.10 Trade-Offs in Gene Expression |
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258 | (1) |
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14.11 Division of Labor in the Individual Cells That Make Up an Organ |
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259 | (1) |
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14.12 Variation within a Species Lies on the Pareto Front |
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260 | (3) |
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263 | (1) |
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263 | (8) |
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271 | (2) |
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273 | (14) |
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15.1 The Astounding Speed of Evolution |
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273 | (1) |
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15.2 Modularity Is a Common Feature of Engineered and Evolved Systems |
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273 | (1) |
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15.3 Modularity Is Found at All Levels of Biological Organization |
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274 | (1) |
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15.4 Modularity Is Not Found in Simple Computer Simulations of Evolution |
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275 | (1) |
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15.5 Simulated Evolution of Circuits Made of Logic Gates |
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275 | (3) |
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15.6 Randomly Varying Goals Cause Confusion |
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278 | (1) |
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15.7 Modularly Varying Goals Lead to Spontaneous Evolution of Modularity |
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278 | (2) |
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15.8 The More Complex the Goal, the More MVG Speeds Up Evolution |
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280 | (1) |
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15.9 Modular Goals and Biological Evolution |
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281 | (2) |
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283 | (1) |
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283 | (1) |
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284 | (3) |
Appendix A The Input Functions of Genes: Michaelis-Menten and Hill Equations |
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287 | (12) |
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A.1 Binding of a Repressor to a Promoter |
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287 | (2) |
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A.2 Binding of an Inducer to a Repressor Protein: The Michaelis-Menten Equation |
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289 | (2) |
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A.3 Cooperativity of Inducer Binding and the Hill Equation |
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291 | (1) |
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A.4 The Monod-Changeux-Wyman Model |
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292 | (1) |
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A.5 The Input Function of a Gene Regulated by a Repressor |
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293 | (1) |
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A.6 Binding of an Activator to Its DNA Site |
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294 | (1) |
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A.6.1 Comparison of Dynamics with Logic and Hill Input Functions |
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295 | (1) |
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A.7 Michaelis-Menten Enzyme Kinetics |
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295 | (2) |
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297 | (1) |
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297 | (1) |
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298 | (1) |
Appendix B Multi-Dimensional Input Functions |
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299 | (4) |
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B.1 Input Function That Integrates an Activator and a Repressor |
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299 | (2) |
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301 | (1) |
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301 | (2) |
Appendix C Graph Properties of Transcription Networks |
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303 | (4) |
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C.1 Transcription Networks Are Sparse |
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303 | (1) |
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C.2 Transcription Networks Have Long-Tailed Out-Degree Sequences and Compact In-Degree Sequences |
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303 | (2) |
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C.3 Clustering Coefficients |
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305 | (1) |
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C.4 Quantitative Measure of Network Modularity |
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305 | (1) |
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306 | (1) |
Appendix D Noise in Gene Expression |
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307 | (6) |
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307 | (1) |
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D.2 Extrinsic and Intrinsic Noise |
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307 | (1) |
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D.3 Distribution of Protein Levels |
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308 | (1) |
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D.4 Network Motifs Affect Noise |
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309 | (1) |
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D.5 Position of Noisiest Step |
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310 | (1) |
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311 | (1) |
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311 | (2) |
Words Of Thanks |
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313 | (2) |
Index |
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315 | |