Technion study finds evolution favors flatter paths with equal fitness

Technion researchers have uncovered a previously unrecognized factor influencing evolutionary trajectories, a finding reported in the journal *Proceedings of the National Academy of Sciences*. The study demonstrates that when an organism faces multiple evolutionary routes that confer identical fitness advantages, the choice among those routes is not governed solely by random chance.

The team conducted controlled laboratory experiments using microbial populations engineered to possess several equally beneficial mutations. By tracking the genetic changes over successive generations, they observed consistent biases toward specific pathways, despite the theoretical equivalence of the alternatives. Statistical analysis ruled out stochastic drift as the sole driver, indicating that subtle, non‑random mechanisms—such as microscopic environmental gradients or intrinsic cellular processes—can steer evolution even in a flat fitness landscape.

These results challenge the conventional view that neutral fitness landscapes lead to purely random evolutionary outcomes and suggest that deterministic elements may shape genetic diversity more broadly than previously thought. The findings open new avenues for research into the hidden variables that guide adaptation, with potential implications for fields ranging from antibiotic resistance management to synthetic biology.