A Plant That ‘Can’t Die’ Reveals Its Genetic Secrets


About 86 million years ago, the entire Welwitschia genome doubled, following an error in cell division, increasing drought and prolonged drought in the region – and possibly during the formation of the Namib Desert itself. Tao Wan, a botanist at Fairy Lake Botanical Garden in Shenzhen, China, and lead author of the study. He said “extreme stress” is often associated with such genome duplication events.

Co-author of the study, Dr. Leitch added that the duplicated genes were also released from their original function and potentially recruited new ones.

However, Dr. Having more genetic material comes at a cost, Wan said. “The most fundamental activity for life is DNA replication, so if you have a large genome, it really takes energy to sustain life,” especially in such a harsh environment.

Worse still, much of Welwitschia’s genome is self-replicating “junk” DNA sequences called retrotransposons. Dr. “Now this scrap needs to be reproduced, repaired,” said Leitch.

The researchers detected a “burst” of retrotransposon activity one to two million years ago, most likely due to increased heat stress. But to counteract this, the Welwitschia genome has undergone widespread epigenetic changes that silence this scrap DNA through a process called DNA methylation.

This process, along with other selective forces, greatly reduced the size and energetic maintenance cost of Welwitschia’s replicated DNA library, said Dr. By giving it a “very efficient, low-cost genome,” Wan said.

The study also found that Welwitschia has other genetic tweaks that hide its leaves.

An average plant leaf grows from the tips of the plant or the ends of its trunk and branches. But the original growing tip of the Welwitschia dies, and instead the leaves shed from a vulnerable area of ​​the plant’s anatomy called the basal meristem, which provides fresh cells to the growing plant, Dr. wan. Multiple copies or increased activity of certain genes involved in efficient metabolism, cell growth, and stress resistance in this area may help it continue to grow under extreme environmental stress. In a warming world, the genetic lessons Welwitschia offers could help people grow tougher, less thirsty crops.


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