Gastrulation and mesoderm morphogenesis in the white sturgeon

Area of Science:

• Developmental Biology
• Comparative Embryology
• Ichthyology

Background:

• Gastrulation is a fundamental process in embryonic development across vertebrates.
• Understanding gastrulation in diverse species like the white sturgeon (Acipenser transmontanus) can illuminate conserved and divergent evolutionary pathways.
• Previous research has established detailed models for gastrulation in amphibians, notably Xenopus laevis.

Purpose of the Study:

• To provide a comprehensive morphological description of gastrulation in the white sturgeon.
• To compare sturgeon gastrulation with that of amphibians, particularly Xenopus laevis, to identify shared and distinct developmental mechanisms.
• To establish a foundation for future experimental studies investigating the functional significance of differences in sturgeon gastrulation.

Main Methods:

• Scanning electron microscopy (SEM) for high-resolution surface imaging.
• Histological analysis to examine internal tissue structures.
• Time-lapse filming and video microscopy to capture dynamic developmental processes.

Main Results:

• Identified similarities between white sturgeon and Xenopus laevis gastrula structure and early cellular behaviors (bottle cell formation, involution).
• Documented unique features in sturgeon gastrulation, including an equatorial dorsal lip and a distinct cleft of Brachet.
• Observed ingression of prospective axial mesoderm in the posterior archenteron roof, a process differing from Xenopus but resembling other amphibians.

Conclusions:

• White sturgeon and amphibian embryos share significant developmental mechanisms during gastrulation.
• Specific differences, such as the equatorial dorsal lip in sturgeon, represent variations on common developmental themes.
• Comparative analysis of gastrulation across vertebrate lineages enhances understanding of developmental plasticity and evolutionary conservation.