Guest post: The Largest Organism in the World

Quaking Aspens: these are not the trees you are looking for

I just received this gem from Tony Seidel; here’s Tony to tell us about one big fungus and the tree that is even bigger:

Although this course focuses on the microscopic life, it is sometimes important to take a step back and look at the big picture and see how it relates. The Armillaria ostoyae, better known in Oregon as the Humongous Fungus, was recognized as the largest living organism. It is a 100 ton fungus covers 3.7  in Oregon’s Blue Mountains. The title has recently been given to the Populus tremuloides, or quaking aspen, of Utah. This organism is much larger, sixty times the weight of the fungus at 6000 tons and covers about 0.2 square miles. This may not sound as extensive as the fungus, but its mass is much greater.

The root grows by sending out sprouts, or ramets, to the surface in for energy, which will eventually mature into tall quaking aspens. The quaking aspen trees are all connected and growing from one original root, making this group of trees one specimen. These aspen clones are sometimes mistaken for a forest of trees, when in reality they have identical DNA. One phenotypic response to their identical DNA is observable when their leaves turn colors in the autumn season. Ramets that are the same age will change the same color at the same time.

Modern DNA technology has allowed scientists at the University of Colorado to test the quaking aspens for genetic similarities.  Dr. Jeffry Mitton, the lead researcher, along with Dr. Michael Grant and Dr. Yan Linhart, all aided in the testing and discovery of the largest organism. In order into compare the DNA, they studied the genetic variation in proteins. DNA analysis has become cheaper to perform now that the science of genetics is developing.

This technique of comparing DNA and proteins is also used frequently in microbiology. Microbial control within the human body is obtained by using antibiotic drugs. These antibiotics need to be selectively toxic so that our cells remain unharmed. Finding differences between our DNA and the microbe’s DNA will help our drugs to be more selective in their treatment. Now, genetics has been used to identify the smallest and largest organisms on the earth, which is an ever-changing statement with science and new discoveries.

What a phenomenal find! This is just one of many ways that genetics can help us view the world in a different way; it’s not several trees, it is all one plant. The next time you enter a so called “forest”, realize that you may only be at the tip of the iceberg. (Quaking aspens) (Humongous Fungus) (Humongous Fungus)


About ycpmicro

My name is David Singleton, and I am an Associate Professor of Microbiology at York College of Pennsylvania. My main course is BIO230, a course taken by allied-health students at YCP. Views on this site are my own.

Posted on June 21, 2011, in Guest Post, Microbes in the News, Strange but True and tagged , , . Bookmark the permalink. 4 Comments.

  1. Kristina Sprenkle

    Did they compare the quaking aspens DNA to other trees and fungi? They mentioned the are mistakened for trees but there DNA is identical? But to which? That picture is really neat; there are some areas that look similar to that and I would have never guesses that is fungi growing up or the ramets. That is really interesting, now when I go into the woods I am going to wonder if they are really trees or fungi!

  2. Well, those are definitely trees. According to the story Tony reported, the trees covering a very large area (most of an acre) are all one organism, so that the DNA of each of the trees is identical. Because most of the mass of the tree is above ground, and pretty big as well, these make for one gigantic organism, most of which we can actually see. They are all interconnected underground.

    In the case of the fungus, most of the organism is underground and not visible to the naked eye except where the fruiting bodies (mushrooms) pop up. The Humongous Fungus covers a much larger area than the Aspen trees do though, covering the better part of a square mile. Again, DNA sequencing supports that the entire thing is one gigantic organism!

  3. This is such a bizarre discovery! I would have never thought those were fungi. The fact that the ramets are an extension of the actual fungi underground seems like such an amazing adaptive feature. Instead of growing somewhere it could be compromised the main section of the fungi remains underground, protected, while the roots rise above ground to gain the energy necessary to grow these immense “tree” like structures. I wonder if this occurs with other certain species of “trees” in other parts of the world. I’m sure this can not be the only case.

    • Just to reiterate, the Quaking Aspen is a tree, and not a fungus! The aspens are photosynthetic like all plants, whereas the Humongous Fungus Tony first mentioned feeds via adsorptive feeding by secreting enzymes from underground hyphae.

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