Embryonic development in the acoel Hofstenia miamia

Area of Science:

• Marine biology
• Developmental biology
• Evolutionary biology

Background:

• Acoels, marine worms within the Xenacoelomorpha phylum, represent a deep-diverging bilaterian lineage.
• Studying acoel development is crucial for understanding the evolution of fundamental bilaterian traits.
• Detailed morphological and transcriptomic data for acoel development, especially in species amenable to genetic studies, have been lacking.

Purpose of the Study:

• To establish detailed developmental landmarks for the highly regenerative acoel Hofstenia miamia.
• To generate a comprehensive developmental staging atlas from zygote to hatched worm.
• To provide a resource for future mechanistic investigations into acoel development and evolution.

Main Methods:

• Observation of gross morphology during embryogenesis.
• Generation of bulk transcriptome data alongside morphological staging.
• Detailed documentation of cell cleavage patterns and internalization events.

Main Results:

• A developmental staging atlas for Hofstenia miamia embryogenesis was created.
• The stereotyped 'duet cleavage' pattern was described, involving vegetal macromeres and animal micromeres.
• A novel cell-internalization event at the animal pole was identified, preceding germ layer and body axis formation.

Conclusions:

• The study provides a foundational resource for studying acoel embryogenesis.
• These findings offer insights into the evolution of bilaterian development and regeneration.
• Hofstenia miamia serves as a valuable model for investigating developmental processes in deep-diverging bilaterians.