Practice question

Multicellular organisms originate from single genome but produce hundreds of distinct cell types ranging from contractile muscle to secretory gland cells. Diversity arises not from different DNA content but from selective activation and silencing of genes in each lineage, termed differential gene expression. Transcription factors, chromatin modifiers like Polycomb, DNA methylation, and non-coding RNAs regulate accessibility. Enhancers and promoters respond to signaling cues Wnt, Notch, Hedgehog, creating cell-type-specific transcriptomes. Identical genotype translates into varied proteomes and morphologies, illustrating how genomic equivalence coupled with regulatory heterogeneity underpins cellular differentiation and functional specialization.