On the Maxillofacial Development of Mice, Mus musculus

Area of Science:

• Evolutionary biology
• Developmental biology
• Comparative anatomy

Background:

• The evolution of the vertebrate maxillofacial region, particularly upper jaw bone homology, remains debated.
• Understanding murine cranial development is crucial for comparative studies but detailed descriptions are limited.

Purpose of the Study:

• To provide a detailed description of murine maxillofacial development from pharyngula to late fetal stages.
• To investigate the homology of mammalian upper jaw bones and their evolutionary origins.
• To establish a framework for comparative craniofacial research.

Main Methods:

• Three-dimensional reconstructions of histological sections from mouse embryos (9.0 to 18.5 days post-coitum).
• Analysis of facial skeleton, nerves, and vasculature development.
• Comparative morphological analysis with nonmammalian tetrapods and humans.

Main Results:

• Murine pharyngula stages and chondrocranium development are highly conserved compared to other tetrapods and humans.
• The Os incisivum is proposed to comprise septomaxillary and palatine components.
• Evidence supports the hypothesis that the ancestral mammalian premaxilla was lost.

Conclusions:

• Detailed description of mouse facial development enhances anatomical correspondence with humans.
• Findings support a revised model for mammalian upper jaw evolution.
• This study provides a foundation for future comparative craniofacial research across vertebrates.