Stonehill breaks new ground on evolution
New research, conducted by biology faculty and students over more than fifteen years and published in Scientific Reports, identifies a genetic variation in mushrooms that may allow individual organisms to undergo adaptive changes within a single lifetime.
Walk in the woods lately? If so, you may have noticed big clumps of mushrooms growing from the bases of trees. In many cases, these clumps are honey mushrooms, which pop up each fall from a vast underground network forming a single individual organism.
In fact, this unassuming fungus, also known as Armillaria gallica, is the largest living organism in the world. More than that, one individual network of fungus can also:
- live for more than 2000 years;
- cover almost 200 acres; and
- weigh as much as three blue whales.
These remarkable facts prompt the question—how can fungal individual organisms live so long and grow to be so large?
Stonehill biology professors have been exploring that very question since 2004. Professors Diane Peabody, Robert Peabody and Maura Tyrrell, all now retired, initially began the research and they were subsequently joined by professors Rachel Hirst and Magdalena James-Pederson.
In addition, more than 20 students working in the Stonehill Undergraduate Research Experience (SURE) summer program or in laboratories during the academic year have also participated in this research. And funding from SURE, the National Science Foundation, and the Fr. Francis Hurley C.S.C. Chair in Biology helped make it happen.
Their most recent study, "Mosaic fungal individuals have the potential to evolve within a single generation," was published recently in the online journal, Scientific Reports.
What’s new is that our biology faculty and students have discovered a form of genetic variation that exists within the bodies of single fungal individual organisms; and they think these mosaics of genetically different cells allow individual organisms to undergo adaptive changes within a single lifetime.
To understand how this process might work, Professor Emeritus Robert Peabody suggests that we think about what might happen if humans were genetic mosaics.
“Imagine catching a disease that kills some of your cells, but not all of them; then, having other cells possessing different combinations of your genes allowing you to recover and move on with your life,” says Peabody, one of the 27 faculty and student coauthors who completed this decade-long study.
Collectively the team thinks this form of genetic mosaicism may explain the sizes and longevities of individual honey mushroom networks.
“Perhaps it also explains how they function so well as ecologically important forest decomposer-recyclers and sometimes as plant pathogens causing enormous economic damage to timberlands, orchards, and vineyards around the world,” says Professor Maura Tyrrell who retired from teaching in 2016.
The key to this may be a form of adaptation that takes place within a single generation. The concept of adaptation is not new. What is novel is that mosaicism may allow adaptation to take place within a single generation.
“Adaptation is just the process by which natural selection allows a population of organisms to become better suited to its environment. The structural changes usually occur over many generations, as better suited organisms leave more descendants than others,” explains Peabody.
He adds “Consider human populations exposed to malaria. Populations with historically greater exposures have used the genetic variation in eggs and sperm to develop a degree of resistance to the disease.”
Similarly, every fall, honey mushrooms produce spores that are as genetically variable as human eggs and sperm; and this variation allows generation-to-generation responses to changing environments.
But honey mushrooms have an additional form of genetic variation: differences in cells within the network forming a mosaic allowing functional changes within a single generation.
“Some of our professors who worked on this in the early days are now retired. Some of our SURE students who collaborated with us on this project are now scientists with doctorates. Some are physicians or dentists and many others are in allied health fields,” notes Professor Diane Peabody who adds that an additional six Stonehill alumni were coauthors of published honey mushroom research.
The long-term, collaborative nature of this research is a hallmark of the College’s Biology Department according to Dean of the College’s May School of Arts & Sciences Peter Ubertaccio.
“The publication of this research in Scientific Reports reflects our Department’s commitment to primary research, partnering with students and rigorously pursuing lines of scholarly investigation,” adds Dean Ubertaccio.
|Year of research||Contributor|
|Ongoing||Professor Rachel Hirst, Ph.D.|
|Ongoing||Professor Magdalena James-Pederson, Ph.D.|
|Ongoing||Professor Emerita Diane C. Peabody, Ph.D.|
|Ongoing||Professor Emeritus Robert B. Peabody, Ph.D.|
|Ongoing||Professor Maura G. Tyrrell, Ph.D.|
|2004||Heather Bickford '06|
|2004||Amy (Curdie) Shafrir '06|
|2004||Robert Doiron '06|
|2006||Amber Churchill '08|
|2006||Juan Carlos Ramirez-Tapia '07|
|2006||Benjamin Seidel '07|
|2006||Lynes Torres '08|
|2008||Kathryn Fallavollitta '10|
|2008||Thomas Hernon '09|
|2008||Lindsay (Prescott) Wiswell '09|
|2008||Sarah Wilson '10|
|2010||Erica Mondo '11|
|2010||Kathleen Salisbury '11|
|2012||Patrick Cabral '13|
|2012||Lauren (Dulieu) Presti '13|
|2013||Kelsey McKenna-(Hoffman) '13|
|2013||Michele Flannery '13|
|2013||Kaitlin Daly '14|
|2013||Darius Haghighat '16|
|2014||Daniel Lukason '15|