Coronavirus (Covid-19): Latest updates and information
Skip to main content Skip to navigation

Martin Howard (John Innes Centre, Norwich)

Modelling noisy concentration gradients in developmental biology



Many biological systems require precise positional information to function correctly. A prominent example is the determination of cell fate during embryonic development. This positional information is often encoded in concentration gradients of morphogen proteins. By switching on a signal only where the local concentration is above a certain threshold, this gradient can provide positional information. However, intrinsic randomness in biochemical reactions and diffusion, as well as external embryo-to-embryo fluctuations, will lead to unavoidable variation in the concentration profile, which in turn will lead to fluctuations in the identified position. We therefore investigated how precisely a noisy concentration gradient can specify positional information. We found that both the kinetic parameters and the overall functional form of a concentration gradient can be optimised to generate maximally precise positional information. We have also analysed fluctuation in gradients that have not reached steady-state. Here we conclude that pre-steady-state read out of morphogen gradients does not generally lead to more precise positional information, contrary to earlier claims.