Biophysical ambiguities prevent accurate genetic prediction

Area of Science:

• Molecular biology
• Genetics
• Biophysics

Background:

• Predicting the combined effects of genetic mutations on phenotypes, fitness, and disease is a central goal in biology.
• It is commonly assumed that mutations combine additively or with predictable interactions.

Purpose of the Study:

• To investigate the predictability of combined mutation effects using simulations.
• To challenge the assumption of additive or predictable interactions in mutation combination.

Main Methods:

• Computational simulations were employed.
• The study focused on the lambda phage transcription factor CI, which represses a gene.

Main Results:

• The assumption of predictable mutation interactions was shown to be incorrect, even for a simple system.
• Perfect measurements of individual mutation effects and mechanistic understanding were insufficient to predict double mutant outcomes.
• Different biophysical effects underlying the same phenotypic change create ambiguity in predicting combined effects.

Conclusions:

• The outcome of combined mutations depends on unobserved biophysical changes.
• Pleiotropy and non-monotonic functions further complicate the prediction of mutation interactions.
• Resolving biophysical ambiguities through additional measurements is sometimes necessary for accurate prediction of phenotypes and disease.