What is "canalisation"

n. The conversion of a river or other waterway to a canal.

1. n. the production of a canal or a conversion to canals [syn: canalization]

2. management through specified channels of communication [syn: channelization, channelisation, canalization]

Canalisation (or canalization) is a measure of the ability of a population to produce the same phenotype regardless of variability of its environment or genotype. In other words, it means robustness. The term canalisation was coined by C. H. Waddington, who used the word to capture the fact that "developmental reactions, as they occur in organisms submitted to natural selection...are adjusted so as to bring about one definite end-result regardless of minor variations in conditions during the course of the reaction". He used this word rather than robustness to take into account that biological systems are not robust in quite the same way as, for example, engineered systems.

Biological robustness or canalisation comes about when developmental pathways are shaped by evolution. Waddington introduced the epigenetic landscape, in which the state of an organism rolls "downhill" during development. In this metaphor, a canalised trait is illustrated as a valley enclosed by high ridges, safely guiding the phenotype to its "fate". Waddington claimed that canals form in the epigenetic landscape during evolution, and that this heuristic is useful for understanding the unique qualities of biological robustness.