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Updated: Jun 6, 2026
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An Integrated Workflow to Study the Promoter-Centric Spatio-Temporal Genome Architecture in Scarce Cell Populations
Published on: April 21, 2023
Studying the evolution of promoter sequences: a waiting time problem
Sarah Behrens1, Martin Vingron
1Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany. sbehrens@molgen.mpg.de
Summary
New transcription factor (TF) binding sites emerge rapidly on evolutionary timescales. TF binding site composition critically influences this emergence time, with CpG processes potentially accelerating TF site creation.
Area of Science:
- Evolutionary genomics
- Computational biology
- Molecular evolution
Background:
- Understanding the evolutionary dynamics of regulatory DNA sequences is crucial for deciphering gene regulation.
- Transcription factor (TF) binding sites are key regulatory elements, and their emergence patterns are not fully understood.
Purpose of the Study:
- To determine the waiting time for the random emergence of TF binding sites in promoter sequences.
- To investigate how the sequence composition of a TF binding site influences its emergence time.
- To assess the evolutionary timescale of TF binding site creation relative to speciation events.
Main Methods:
- Employed two probabilistic models: an independent and identically distributed (i.i.d.) model and a neighbor-dependent model.
- Calculated expected waiting times for k-mers (length 5-10) representing TF binding sites in promoter sequences.
- Screened existing TF binding sites to compare predicted waiting times with observed frequencies.
Main Results:
- New TF binding sites can emerge on short evolutionary timescales, potentially faster than human-chimp speciation.
- The specific composition of a TF binding site significantly impacts its waiting time for random appearance.
- The CpG methylation-deamination substitution process may accelerate the creation of novel TF binding sites.
- k-mers with shorter predicted waiting times are found more frequently among existing TF binding sites.
Conclusions:
- TF binding site evolution can occur rapidly, suggesting dynamic regulatory landscape changes.
- Sequence composition is a key determinant in the evolutionary rate of TF binding sites.
- CpG-mediated mutations likely play a role in generating new regulatory sequences.
- The observed frequency of TF binding sites aligns with predictions based on their evolutionary emergence rates.
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