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#Id: 4788

#Unit 5. Developmental Biology

P2 cell establishes the

dorsal-ventral axis of C. elegans and confers on the ABp blastomere a fate different from that of its sister cell.

TLS Online TPP Program

#Id: 4789

#Unit 5. Developmental Biology

In embryos whose mothers have mutant glp-1, ABp is transformed into an ABa cell

TLS Online TPP Program

#Id: 4790

#Unit 5. Developmental Biology

If the P2 cell is killed at the early 4-cell stage, the ABp cell does not generate its normal complement of cells

TLS Online TPP Program

#Id: 7155

#Unit 5. Developmental Biology

Cleavage type- Unequal radial holoblastic cleavage

TLS Online TPP Program

#Id: 7156

#Unit 5. Developmental Biology

Cortical Rotation The cortical cytoplasm has rotated 30º relative to the internal cytoplasm.

TLS Online TPP Program

#Id: 7157

#Unit 5. Developmental Biology

Gray Crescent 

The region opposite the point of sperm entry, where the greatest displacement of cytoplasm occurs (Gastrulation will begin)

Vegetal rotation: Vegetal cells asymmetrically press up against the inner blastocoel roof on the dorsal side.

Bottle cell formation and invagination: Localized apical constriction at the dorsal blastopore lip creates anisotropic forces that foster invagination.

Involution and cell migration: The leading edge of invaginating cells crawls up onto the blastocoel roof.

Convergence and extension: The targeted medial-to-lateral intercalation of cells on the midline (convergence) drives anterior-posterior axis elongation (extension).