Dolly the cloned sheep aged incredibly fast and died young because her genetic blueprint was copied from an adult mammary gland cell that had already shredded its protective DNA…

A closer look

Cloning a sheep was cool until scientists realized they basically put an old lady's biological clock into a baby's body. Telomeres are the protective "aglets" at the ends of your shoelace-like DNA strands, and they get shorter every time a cell divides. Dolly the sheep was cloned from a 6-year-old adult cell. Because her starting DNA already had severely depleted telomeres, she was born biologically middle-aged. She rapidly developed severe arthritis and lung disease, definitively proving that cellular aging is aggressively hardcoded into our genetic endpoints.