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In Shark Bay, at the westernmost tip of Australia, seagrass meadows line the ocean floor, rippling in the current and being gnawed at by dugongs, cousins of Florida manatees. A new study has revealed something unexpected about these seagrass: Many are the same plant that has cloned itself for nearly 4,500 years.
Seagrass—not to be confused with seaweed, which is an algae—is Poseidon’s tapegrass or Posidonia australis. Jane Edgeloe, PhD Candidate from the University of Western Australia and author of the paper, likens it to a spring onion.
Ms. Edgeloe and her colleagues made their discovery as part of a genetic study of Posidonia grasses in different parts of Shark Bay. Posidonia from 10 different meadows. On land, the researchers analyzed and compared the DNA of the grasses.
They published their results Wednesday in the journal Proceedings of the Royal Society B.. It turns out that the DNA of many of the apparently different plants is almost identical. Elizabeth Sinclair, also from the University of Western Australia and author of the study, recalled the excitement in the lab when she realized that “It’s just a plant.”
Some of the northern meadows of Shark Bay reproduce sexually, while the rest of Posidonia clones itself by forming new shoots that break off from the root system. Even the separate grasslands were genetically identical, suggesting that they were once linked by severed roots. Based on how old the bay is and how fast the seagrass grows, the researchers estimate the Shark Bay clone to be around 4,500 years old.
Besides being a clone, grass appears to be a hybrid of the two species and has two full sets of chromosomes, a condition called polyploidy. While polyploidy can be lethal to animal embryos, it can be harmless and even helpful in plants. But it can cause sterility: Most clonal grasses do not bloom and can only reproduce by continuing to clone itself.
This combination of extra genes and cloning may have been key to the survival of grasses in the ancient era of climate change: Cloning made breeding easier because the grass didn’t have to go to the trouble of finding a mate. Dr. The extra genes may have given seagrass “the ability to cope with a wide variety of conditions,” Sinclair said. Dr. sinclair
Shark Bay Posidonia not only survived this ancient climate change, it spread. And it spread. And post some more.
Today, it is arguably the largest living organism in the world. Pando of Utah, A clonal colony of 40,000 poplar trees It is the “biggest individual plant”, which covers an area of more than 80 football fields and is connected by its roots. Humongous Fungus even biggerIt weaves a web of mycelial branches underground and under the bark over 3.5 square miles of Oregon’s Malheur National Forest. By comparison, the Shark Bay clonal seagrass is 77 square miles, about the size of Cincinnati.
As the Shark Bay clone reaches enormous size and age, the question remains whether it can withstand modern climate change. Julia Harenčár, Ph.D. A candidate at the University of California, Santa Cruz, who was not involved in the study praised the project for “trying to understand in greater detail why polyploidy is advantageous at these major environmental inflection points” that could offer lessons for the climate crisis.
Conservation of seagrass is particularly important, says Marlene Jahnke, a biologist at the University of Gothenburg in Sweden. Along with purifying water and storing atmospheric carbon, they are “truly comparable to coral reefs in the sense that they are home to many other species,” she added.
While the risks are high for seagrass, Dr. Sinclair remains hopeful that Shark Bay Posidonia will retain its status as the world’s largest living plant: While it was damaged in a heatwave from 2010 to 2011, “we’ve seen a lot. More increase in shoots, much more leaf density, that is, it gets better.” “I think this polyploid is probably in pretty good shape in terms of persistence.”
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