Canalized Morphogenesis Driven by Inherited Tissue Asymmetries in Hydra Regeneration

Area of Science:

• Developmental biology
• Regenerative medicine
• Animal morphogenesis

Background:

• Body axis emergence and stabilization are crucial for animal development, defining symmetry and polarity.
• Hydra regeneration exhibits strong memory of axis polarity, even in small tissue fragments.
• Understanding the mechanisms behind this memory is key to comprehending developmental processes.

Purpose of the Study:

• To investigate the processes underlying axis polarity memory in regenerating Hydra.
• To explore how Hydra develop an ordered body plan from convoluted initial conditions.
• To elucidate the interplay of mechanical and biochemical factors in establishing developmental trajectories.

Main Methods:

• Studying regenerating Hydra tissue strips under frustrating initial conditions.
• Inducing tissue strips to fold into hollow spheroids by adhering opposite polarities.
• Observing tissue rearrangements and pattern formation during regeneration.

Main Results:

• Regenerating Hydra tissue strips consistently develop an ordered body plan, preserving original polarity.
• Despite complex folding and rearrangement, a reproducible developmental trajectory is observed.
• Weak inherited cues from the parent animal bias the developmental outcome.

Conclusions:

• Axis polarity memory in Hydra arises from the integration of mechanical and biochemical processes with mutual feedback.
• This integration leads to dynamic canalization, attracting tissue dynamics towards a defined developmental path.
• Hydra regeneration exemplifies a developmental process where dynamic rules are instilled, but the trajectory is not strictly programmatic.