Rhombencephalic neural crest segmentation is preserved throughout craniofacial ontogeny

Area of Science:

• Developmental Biology
• Craniofacial Development
• Neuroscience

Background:

• Craniofacial patterning is complex, involving contributions from various embryonic tissues.
• The precise role of hindbrain segmentation in guiding neural crest cell fate and craniofacial structure remains incompletely understood.

Purpose of the Study:

• To investigate how hindbrain segmentation influences craniofacial patterning.
• To map the long-term fate of individual rhombomere-derived neural crest subpopulations in craniofacial development.

Main Methods:

• Utilized quail-chick chimeras to trace neural crest cell lineages.
• Mapped skeletal and muscle connective tissues derived from specific rhombomeres.

Main Results:

• Demonstrated a composite origin for the mandibular arch skeleton, with distinct contributions from midbrain and hindbrain rhombomeres.
• Revealed that lower jaw and tongue skeletons reflect the rostrocaudal order of hindbrain crest deployment.
• Identified cryptic intraskeletal boundaries defined by rhombomere-specific crest contributions.
• Showcased a constrained skeletomuscular connectivity pattern where rhombomeric populations remain coherent, forming both connective tissues and attachment sites.
• Observed rhombomere-specific matching of muscle connective tissues and attachment sites in the viscerocranium.

Conclusions:

• Hindbrain segmentation acts as a fundamental organizer of craniofacial skeletomuscular patterns.
• The coherence of rhombomere-specific neural crest populations explains the implementation and conservation of cranial patterns during evolution.