Science Current Events | Science News |

Notre Dame research into oaks helps us understand climate change

August 03, 2012

Jeanne Romero-Severson, associate professor of biological sciences at the University of Notre Dame, and her collaborators, are tracking the evolution of the live oaks of eastern North America, seeking to understand how the trees adapted to climate change during glacial periods.

When the ice advanced, the oaks retreated. When the ice retreated the oaks advanced, spreading from tropical to temperate zones, up from Central America and Mexico into the Piedmont Carolinas. The researchers expect the study of live oak migrations and phylogeny will provide clues to the success of the oaks that range up into northern Ontario in Canada.

Oaks originated in southeast Asia before the continents split and migrated both east and west, but North America has far more species than other regions. Researchers have long suspected that repeated climate challenges might have led to this diversity. Previous studies have shown that the live oaks that live in Mexico cannot survive the Carolina winters. This shows that there are genetic differences between the southern live oaks and their northern descendants.

"In Mexico, live oaks do not experience repeated cycles of freezing and thawing," Romero-Severson says. "Are the live oak species that now live further north different species because of this cold tolerance? What about the live oak species that span the tropical-temperate divide? It is logical to assume there is a genetic basis for the ability to survive in those cold temperatures. With four groups of researchers working together, we can tease out how it was that oaks were able to adapt to the climate as they moved north. What were the genetic changes they underwent?"

Romero-Severson focuses on genetics and genomics of the oaks. Andrew Hipp of the Morton Arboretum in Lisle, Ill., is studying their morphological differences; Paul Manos of Duke University is studying their systematics (family trees based on DNA markers); and Jeannine Cavender-Bares of the University of Minnesota is studying their ecophysiology, including the survival of seedlings in cold temperatures. A National Science Foundation grant supports the research.

The team hypothesizes that trees in contact with relatives who could just manage to survive in the cold were able to "capture" from these relatives a few genes favorable for survival in colder climates, without retaining extensive genetic changes that would alter their morphology. Different animal species rarely hybridize in nature and when they do, the offspring are often sterile, like mules. Different forest tree species often make fertile interspecific hybrids, but the parent species remain morphologically distinct.

"It's a mystery to us how oak species can have rampant interspecies hybridization and yet maintain species distinction, but they do," Romero-Severson says. "Favorable gene combinations from one live oak species can be captured by any other live oak species." There might be an "interspecific hybrid screen," a process that retains a relatively small number of good genes that equip the species for successful northward migration, while maintaining all the other genes that determine species identity.

Identification of the genetic changes in the relatively small number of live oak species in the southeastern United States and Mexico can provide clues for study of the more extensive deciduous red and white oaks, which reach from the Caribbean into California to the west and up into Canada from the east. Eastern North America alone has more than two dozen red oak species and close to two dozen white oak species. Some regions in the southeastern United States have the highest concentration of oak species in the world.

"Our hypothesis is that the same set of genes is involved in cold tolerance in all of these species," Romero-Severson says. "We feel that we have defined the problem so carefully that what we learn from these live oaks will help us understand how evolution works, and how natural adaptation arises. Our goal is to understand the role of hybridization in the evolution of forest trees and how forest trees actually respond to rapid climate change."

Romero-Severson, who came to Notre Dame in 2003, is also part of a team of researchers from seven universities with an NSF grant to develop genomics tools for finding the genetic basis for tolerance to the introduced insects and diseases that threaten the nation's hardwood trees.

University of Notre Dame

Related Climate Change Current Events and Climate Change News Articles

Arctic Ocean methane does not reach the atmosphere

Expert urges voluntary family planning to mitigate climate change
With climate change already close to an irreversible tipping point, urgent action is needed to reduce not only our mean (carbon) footprints but also the "number of feet" - that is, the growing population either already creating large footprints or aspiring to do so, argues a leading physician and environmentalist in The BMJ today.

Organism responsible for paralytic shellfish poisoning may affect fisheries

Deep, old water explains why Antarctic Ocean hasn't warmed

Remains of bizarre group of extinct snail-eating Australian marsupials discovered
Fossil remains of a previously unknown family of carnivorous Australian marsupials that lived 15 million years ago have been discovered at the Riversleigh World Heritage Fossil Site in north-western Queensland by a UNSW Australia-led team of researchers.

Mars is emerging from an ice age

SwRI scientists discover evidence of ice age at martian north pole
Using radar data collected by NASA's Mars Reconnaissance Orbiter, a Southwest Research Institute-led team found evidence of an ice age recorded in the polar deposits of Mars.

Underwater grass beds have ability to protect and maintain their own health
An expansive bed of underwater grass at the mouth of the Susquehanna River has proven it is able to "take a licking and keep on ticking."

With spring now fully sprung, a new study by University of Wisconsin-Madison researchers shows that buds burst earlier in dense urban areas than in their suburban and rural surroundings. This may be music to urban gardeners' ears, but that tune could be alarming to some native and migratory birds and bugs.

Coral bleaching 'lifeboat' could be just beneath the surface
A report commissioned by the United Nations and co-authored by the University of Sydney's UNESCO Chair in Marine Science offers a glimmer of hope to those managing the impact of bleaching on the world's coral reefs, including the Great Barrier Reef.
More Climate Change Current Events and Climate Change News Articles

This Changes Everything: Capitalism vs. The Climate

This Changes Everything: Capitalism vs. The Climate
by Naomi Klein (Author)




Climate Change: The Facts

Climate Change: The Facts


Climate Change: What Everyone Needs to KnowÂ®

Climate Change: What Everyone Needs to Know®
by Joseph Romm (Author)



The Sixth Extinction: An Unnatural History

The Sixth Extinction: An Unnatural History
by Elizabeth Kolbert (Author)



Climate Change: The Climate Change Agenda - World Government, Carbon Taxes & Population Control (Climate Change, Global Warming, World Government)


Understand the New Global Realities of Climate Change!
What Is Climate Change? How Did We Cause It? What is the Climate Change Agenda?
When you download Climate Change: The Climate Change Agenda - World Government, Carbon Taxes and Population Control, you’ll dive into a complex and exciting real-world adventure.
This book helps you understand the science, politics, and future projection of climate change – and how to survive it!
From Carbon Taxing to “Cap and Trade”, Climate Change: The Climate Change Agenda - World Government, Carbon Taxes and Population Control explains the political myths, realities surrounding climate change, the effects of climate change on food...


by G. Dedrick Robinson (Author), Gene D. Robinson III (Author)

Global Warming-Alarmists, Skeptics & Deniers: A Geoscientist looks at the Science of Climate Change, brings a unique geological perspective to this politically charged issue, a perspective that has been ignored far too long. Written by a father-son team of geoscientist and attorney, it is the concise guide to the global warming controversy that has been long needed. As a university professor and research geologist for thirty years, Dr. Robinson knows that geological science is essential for placing the global warming controversy in proper prospective. One cannot hope to understand how humans might be causing climate change without an understanding of the magnitude and speed natural processed are capable of when it comes to climate change. Earth history is the only yardstick we have to...

Dire Predictions, 2nd Edition: Understanding Climate Change

Dire Predictions, 2nd Edition: Understanding Climate Change



by George Marshall (Author)


The Thinking Person's Guide to Climate Change

The Thinking Person's Guide to Climate Change
by Robert Henson (Author)




by Orrin H. Pilkey (Author), Linda Pilkey-Jarvis (Author), Keith C. Pilkey (Author)

Melting ice sheets and warming oceans are causing the seas to rise. By the end of this century, hundreds of millions of people living at low elevations along coasts will be forced to retreat to higher and safer ground. Because of sea-level rise, major storms will inundate areas farther inland and will lay waste to critical infrastructure, such as water-treatment and energy facilities, creating vast, irreversible pollution by decimating landfills and toxic-waste sites. This big-picture, policy-oriented book explains in gripping terms what rising oceans will do to coastal cities and the drastic actions we must take now to remove vulnerable populations.The authors detail specific threats faced by Miami, New Orleans, New York, and Amsterdam. Aware of the overwhelming social, political, and...

© 2016