Which of the following best describes the specification of P1 and AB blastomeres in C. elegans?
In early C. elegans embryo, P1 inherits posterior determinants including P-granules, SKN-1, PIE-1 from asymmetric division driven by PAR proteins, giving autonomous specification independent of neighbors. Isolated P1 continues producing EMS and P2 lineages in culture. Conversely AB blastomere requires glp-1/Notch signaling contact between ABp and P2, involving LAG-2/APX-1 ligands to distinguish ABa from ABp fates. Isolated ABa both produce identical ABa-like lineages lacking pharyngeal differences. Thus P1 fate is maternally determined autonomously, while AB division relies on conditional indu
Ref: Gilbert, Developmental Biology, 12th ed., Chapter 4: C. elegans early cleavage - autonomous versus conditional specification of P1 and AB.
