Practice question

Mosaic development represents strictly autonomous specification where each blastomere inherits different maternal cytoplasmic determinants during cleavage. These localized mRNAs and proteins activate lineage-specific transcription programs independently of neighboring cells. When isolated, a mosaic blastomere forms only its predetermined partial structure, never a complete embryo, demonstrating internally programmed fate. Classic examples include tunicates and ascidians, where ablation of a blastomere permanently eliminates its derived tissues without compensation. This contrasts regulative development where cell communication rescues missing parts through inductive signaling and community effects restoring normal pattern.