A Genetic Elixir of Life Helps Millennia-Old Ginkgo Trees Escape Death
These trees have developed an army of molecular weapons to stay healthy in old age
Nestled in the courtyard of China’s Gu Guanyin Buddhist Temple is a ginkgo tree (Ginkgo biloba) that’s been quietly shedding its leaves for 1,400 years. From its unassuming outpost in the Zhongnan Mountains, the tree has outlived the rise and fall of the Ottoman Empire, and the scourge of the Black Plague. It saw electricity revolutionize human history and watched the world’s greatest powers descend into the chaos of war twice over.
This long-lived tree will probably still be around for decades, centuries or even millennia to come. For the ginkgo, and perhaps other plants, it seems “the default condition … is immortality,” says Howard Thomas, a plant biologist from Aberystwyth University, to Science magazine’s Erin Malsbury.
Now, researchers are starting to uncover some of the botanical secrets behind the ginkgo’s astounding longevity—a concept we fast-aging humans may struggle to fathom, let alone replicate for ourselves. Per a study published this week in the Proceedings of the National Academy of Sciences, ginkgo trees don’t decline much as they age. Instead, the trees continue to pump out protective chemicals; unlike many other organisms, they don’t seem cellularly programmed to die.
While elderly humans more easily succumb to disease, the immune system of a 1,000-year-old ginkgo tree essentially “looks like that of a 20-year-old,” study author Richard Dixon, a biologist at the University of North Texas, tells the New York Times’ JoAnna Klein. And though the growth of other organisms typically peters out as time goes on, ancient ginkgos barrel on as if nothing’s changed. Their staying power is even observable by the naked eye: Centuries-old trees bear just as many seeds and leaves as young ones.
To come to these conclusions, Dixon and his colleagues compared DNA from young and old ginkgos, focusing on cells from the leaves, as well as the cambium, a type of tissue that sprouts between a tree’s internal wood and external bark. In more aged trees, genes responsible for thickening the cambium were less active, and cell division appeared to slow down, yielding thinner swaths of tissue.
But for the most part, geriatric ginkgos didn’t show their age. Genes coding for the production of antioxidants and antimicrobials were highly active in trees both old and young, helping the plants stave off infections. And while fan-shaped ginkgo leaves would eventually wither, yellow and die, cells in the cambium didn’t deteriorate in the same way, in part because they didn’t express genes that prompted senescence, the final stage of life.
If all this molecular machinery keeps churning on indefinitely, ginkgos could theoretically be immortal, Peter Brown, a biologist who runs Rocky Mountain Tree Ring Research and was not involved in the study, tells the New York Times. But immortality isn’t invincibility: The trees still regularly die from pests, droughts, human development, and other stressful, damaging events.
That’s okay, though. Were ginkgo trees to never die, the world would be an awfully crowded place without much room for other spectacularly long-lived organisms, like this death-defying jellyfish. Even among arboreals, the ginkgo is in good company: As Leslie Nemo reports for Discover magazine, redwoods, too, can live for thousands of years, and English yews aren’t considered “old” until they reach their 900s. Even a 4,800-year-old bristlecone in California can throw its hat into the ring. Trees, it seems were the original millennials.