“…This latter concept has been decribed as developmental constraint or developmental bias (Maynard Smith et al, 1985;Arnold, 1992;Cheverud, 1984;Rohner & Berger, 2023), which may account for the observation that perturbations, such as mutation or environmental variation, to biological systems will tend to produce some phenotypic variants more readily (Uller et al, 2018;Waddington, 1957). In spite of the numerous studies that address genetic correlation as an evolutionary constraint, much confusion and controversy remains over definitions of dif-ferent types of constraint, the mechanism(s) causing constraint, and the relative importance of different mechanisms in shaping evolutionary trajectories (Muir et al, 2022;Conner et al, 2011).…”