Every cell in your body contains the same DNA — but they read completely different chapters
Every cell in your body (with a few exceptions like red blood cells and mature immune cells) contains your complete genome — all 3 billion base pairs. A liver cell, a neuron, a skin cell, and a heart muscle cell all have identical DNA. What makes them different is which genes are expressed. Epigenetic mechanisms — chemical tags on DNA, protein wrapping, RNA regulation — switch genes on and off in different patterns in different cell types. The same 'book' produces thousands of different 'chapters' depending on which pages the cell reads.
We intuitively think of cells as specialised units with specialised DNA. Finding that every cell has the complete DNA manual — and that differentiation is about reading rather than content — makes cell biology feel like an information management problem rather than a hardware problem.
“Every cell in your body has identical DNA — a liver cell and a neuron have the same genome. What makes them different is which genes they 'read'. Same book; completely different chapters. 📖🧬 #OddlyHuman”