In the latest study, reported in a paper published in the journal Science , the researchers induced the production of Myosin 1D in normally symmetrical organs of Drosophila, such as the respiratory trachea.
Quite spectacularly, they say, this was enough to induce asymmetry at all levels: deformed cells, trachea coiling around themselves, the twisting of the whole body, and helicoidal locomotive behaviour among fly larvae. And these new asymmetries always develop in the same direction.
To identify the origin of these cascading effects, they called in biochemists from the University of Pennsylvania in the US, who brought Myosin 1D into contact with actin, a component of the cell’s cytoskeleton or backbone. They observed that the interaction between the two proteins caused the actin to spiral.
The conclusion drawn is that Myosin 1D appears to be a unique protein capable of inducing asymmetry in and of itself: first at the molecular level, then, through a domino effect, at the cell, tissue, and behavioural level.
This suggests a possible mechanism for the sudden appearance of new morphological characteristics over the course of evolution, such as the twisting of snails’ bodies.
If I recall, @Mercer is a researcher on Myosin. It would be great to hear his take on this study.