A towering genome: Experimentally validated adaptations to high blood pressure and extreme stature in the giraffe

A giraffe gene helped mice resist high blood pressure. Supplying a brain at the top of a long neck requires pressures that would be dangerous for many other mammals. Giraffes cope without the expected organ damage, making their DNA a place to look for protective adaptations as well as instructions for growing tall.

Chang Liu, Jianbo Gao, Xinxin Cui and colleagues assembled a high-quality genome from a male Rothschild's giraffe at Guangzhou Zoo and compared it with other mammals. One gene, FGFRL1, carried seven distinctive protein changes. The team introduced those changes into mice, then compared them with ordinary mice receiving a substance that normally raises blood pressure for twenty-eight days.

The ordinary mice developed high blood pressure; the giraffe-type mice resisted that rise and had less associated heart and kidney scarring. Their adult bones also had higher mineral density, but their necks and bodies were not longer. These are mouse experiments, not proof of a treatment for people or a complete explanation of giraffe physiology. They nevertheless turn an unusual giraffe gene into experimental evidence linking the demands of height with both circulation and bone biology.