June 7th, 2006



Evolutionary roads are robust: Siegal and Bergman's study

Invariant traits -- such as having five fingers to a hand instead of four or six -- don't become universal because Nature has somehow selected special genotypes that faithfully direct development of the trait under a wide variety of conditions, the researchers argue. Instead, they show, it is the complexity of our genotypes -- the many genes that interact in networks during development, inhibiting and activating each other and even regulating themselves -- that provides fidelity. Indeed, Bergman and Siegal show that any functional genetic network that is complex enough has this built-in property of fidelity. This is true whether natural selection on the phenotype produced by the network during development is strong, weak or absent. Natural selection may be important in shaping traits that aid in reproduction and survival, but Bergman and Siegal show that it doesn't matter much during development, when, biologically speaking, all roads lead to Rome.

Stanford University News Release

PNAS, 2002
Mark L. Siegal and Aviv Bergman "Waddington's Canalization Revisited: Developmental Stability and Evolution" PDF

Aviv Bergman's Lab: papers