Organisms as polyphasic liquid crystals

We review evidence supporting the concept that organisms are polyphasic liquid crystals and that a liquid crystalline structure is fundamentally involved in biological organization and function, including pattern determination during development. A novel interference colour imaging technique is described, which enables us to detect, non-invasively, liquid crystalline domains in living organisms. The colour intensity is shown to be linearly related to the molecular birefringence and degree of coherent alignment. We demonstrate the use of the quantitative imaging technique to reveal a phase-transition-like increase in colour intensity of the body wall musculature in maturing Drosophila larvae and birefringent patterns in the early embryo when pattern determination processes are known to be occurring. The possible role of electrodynamic activities in pattern determination via phase ordering effects on liquid crystals is discussed.