 |
|
Old developmental pathways spawn revolutionary evolutionary changes
September 07, 2007TEMPE, Ariz. - When the larvae of the primitive social insect Polistes metricus, a paper wasp, slips into the quiet pupal stage, she doesn't know if she'll arise a worker or gyne (future queen) - unless she consults with Arizona State University's social insect researcher Gro Amdam.
Amdam's group is shedding new light on the development of colonial insects from solitary ancestors through study of a primitive social order of wasps. In a paper highlighted on the cover and published Aug. 28 in the Proceedings of the National Academy of Sciences (PNAS), ASU's Amdam and Florian Wolschin teamed up with Kari Norberg, from Amdam's laboratory at the Norwegian University of Life Sciences, and James Hunt and others from the University of Missouri. They reveal that the Polistes larvae that can become future queens show signs of developmental diapause, a period of overt quiescence and a life history trait of many insect orders.
How can the larval environment determine future royal stature" The concept of environmental cues, things like weather, shorter day length, or food availability, determining destiny seems distinctly foreign in humans. However, Amdam, an associate professor in ASU's School of Life Sciences, has pioneered an understanding of how developmental programs underlying diapause and reproduction can be adopted in primitively social settings to result in the complex social behaviors and castes found in advanced insect societies.
"Because the biology and physiology of the Polistes wasp is more 'transparent,' instead of highly derived as is often the case of highly social insects, such as honey bees, we can more easily backtrack, follow the footprints of evolution and uncover the pathways that castes originally evolved from," says Amdam.
Many species of highly social insects have two distinct female castes, workers and queens, with traits set in larval life. However, Amdam points out that the primitive social Polistes wasp was originally believed to lack developmental castes entirely, and to be more like its solitary ancestors. Individual females were thought to simply "choose" to become workers or queens - as adults. However, previous work by Hunt and Amdam, published in Science Magazine in 2005, suggested otherwise, hypothesizing that a bias toward "queen-ness" might occur earlier in life than previously believed, and be tied to an old life history trait, diapause, found in both solitary and social insects.
Hard evidence was provided by the discovery by Hunt, Norberg, Wolschin, Amdam and co-workers of differing hexamerin storage protein levels in Polistes larvae and pupae destined to become workers or gynes. In combination with a prolonged developmental time in gynes, this finding indicates that differential provisioning of the larvae, prior to pupation, serves to promote a caste bias in which a higher level of nourishment results in primarily gyne-destined female wasps. According to Amdam, the developmental program of diapause, that also typifies solitary insects without castes, was "adopted by evolution to produce Polistes females that look the same but differ in their potential to attain two distinct social roles." This adoption, the PNAS paper poses, "provides the foundation for a major developmental switch: the divergence of workers and potentially reproductive gyne castes in some social hymenoptera."
The significance of their research in Polistes is two fold, according to the authors, "it challenges the view that workers and gynes represent behavior options equally available to every female offspring, and it exemplifies how social insect castes can evolve from casteless lineages."
Amdam and her colleagues believe this research brings scientists one step closer to "understanding how developmental programs in solitary insects can be remodeled to yield complex, social orders marked by castes and task specialization."
This isn't the first system in which Amdam has revealed how ancestral programs have been co-opted to promote the evolution of castes. Amdam's group established for the first time how genetic pathways tied to "reproductive and molecular signaling cascades that exist in solitary species may have been utilized to yield reproductive queens, and non-reproductive sisters, workers, in the social order of honey bees." In work published in the journal Public Library of Science One (PLoS One) in 2007, the researchers showed that a key regulator for caste fate was the ancestral protein kinase TOR ('target of rapamycin'), which had become the transducer of the signal determining if a honey bee larva grows to be worker or queen.
"The fact that workers and queens can emerge from ancestral pathways in both complex and more primitive social insects helps us understand what evolution builds from when it produces seemingly radical new phenotypes," Amdam says.
Amdam's innovative approaches with the use of social insect models led to her selection in June 2007 as a "Biomedical Scholar" by The Pew Charitable Trusts, and "Outstanding Young Researcher" by the Research Council of Norway. The resulting $1.8 million in awards will fund her laboratories in ASU's College of Liberal Arts and Sciences and the University of Life Science in Norway, and could potentially lead to new insights into human traits, such as aging, that have likely been molded by social evolution.
Arizona State University
"Because the biology and physiology of the Polistes wasp is more 'transparent,' instead of highly derived as is often the case of highly social insects, such as honey bees, we can more easily backtrack, follow the footprints of evolution and uncover the pathways that castes originally evolved from," says Amdam.
Many species of highly social insects have two distinct female castes, workers and queens, with traits set in larval life. However, Amdam points out that the primitive social Polistes wasp was originally believed to lack developmental castes entirely, and to be more like its solitary ancestors. Individual females were thought to simply "choose" to become workers or queens - as adults. However, previous work by Hunt and Amdam, published in Science Magazine in 2005, suggested otherwise, hypothesizing that a bias toward "queen-ness" might occur earlier in life than previously believed, and be tied to an old life history trait, diapause, found in both solitary and social insects.
Hard evidence was provided by the discovery by Hunt, Norberg, Wolschin, Amdam and co-workers of differing hexamerin storage protein levels in Polistes larvae and pupae destined to become workers or gynes. In combination with a prolonged developmental time in gynes, this finding indicates that differential provisioning of the larvae, prior to pupation, serves to promote a caste bias in which a higher level of nourishment results in primarily gyne-destined female wasps. According to Amdam, the developmental program of diapause, that also typifies solitary insects without castes, was "adopted by evolution to produce Polistes females that look the same but differ in their potential to attain two distinct social roles." This adoption, the PNAS paper poses, "provides the foundation for a major developmental switch: the divergence of workers and potentially reproductive gyne castes in some social hymenoptera."
The significance of their research in Polistes is two fold, according to the authors, "it challenges the view that workers and gynes represent behavior options equally available to every female offspring, and it exemplifies how social insect castes can evolve from casteless lineages."
Amdam and her colleagues believe this research brings scientists one step closer to "understanding how developmental programs in solitary insects can be remodeled to yield complex, social orders marked by castes and task specialization."
This isn't the first system in which Amdam has revealed how ancestral programs have been co-opted to promote the evolution of castes. Amdam's group established for the first time how genetic pathways tied to "reproductive and molecular signaling cascades that exist in solitary species may have been utilized to yield reproductive queens, and non-reproductive sisters, workers, in the social order of honey bees." In work published in the journal Public Library of Science One (PLoS One) in 2007, the researchers showed that a key regulator for caste fate was the ancestral protein kinase TOR ('target of rapamycin'), which had become the transducer of the signal determining if a honey bee larva grows to be worker or queen.
"The fact that workers and queens can emerge from ancestral pathways in both complex and more primitive social insects helps us understand what evolution builds from when it produces seemingly radical new phenotypes," Amdam says.
Amdam's innovative approaches with the use of social insect models led to her selection in June 2007 as a "Biomedical Scholar" by The Pew Charitable Trusts, and "Outstanding Young Researcher" by the Research Council of Norway. The resulting $1.8 million in awards will fund her laboratories in ASU's College of Liberal Arts and Sciences and the University of Life Science in Norway, and could potentially lead to new insights into human traits, such as aging, that have likely been molded by social evolution.
Arizona State University
Evolution Current Events and Evolution News RSSHuman genomics in China
Ten years ago, the Chinese National Human Genome Center at Shanghai (South Center, hereafter) was established in the Zhangjiang HiTech Park of Pudong District in Shanghai. To commemorate this important event, which marks the beginning of the Genomics Era in China, we specially organize a series of mini-reviews for this special issue.
Avian flu becoming more resistant to antiviral drugs, says University of Colorado study
A new University of Colorado at Boulder study shows the resistance of the avian flu virus to a major class of antiviral drugs is increasing through positive evolutionary selection, with researchers documenting the trend in more than 30 percent of the samples tested.
Spookfish uses mirrors for eyes
A remarkable new discovery shows the four-eyed spookfish to be the first vertebrate ever found to use mirrors, rather than lenses, to focus light in its eyes.
Study Yields Clues About the Evolution of Epilepsy
Two children have a seizure. One child never has another seizure. Twenty years later, the other child has a series of seizures and is diagnosed with epilepsy. A study being led by researchers at Rensselaer Polytechnic Institute is looking at what could possibly happen in the development of these two children that would lead to such extreme variations in their neurologic health.
Plant polymerases IV and V are special forms of Polymerase II
It's a little like finding out that Superman is actually Clark Kent. A team of biologists at Washington University in St. Louis has discovered that two vital cellular components, nuclear RNA Polymerases IV and V (Pol IV and V), found only in plants, are actually specialized forms of RNA Polymerase II, an essential enzyme of all eukaryotic organisms, including humans.
Four, three, two, one . . . pterosaurs have lift off
Pterosaurs have long suffered an identity crisis. Pop culture heedlessly -- and wrongly -- lumps these extinct flying lizards in with dinosaurs. Even paleontologists assumed that because the creatures flew, they were birdlike in many ways, such as using only two legs to take flight.
Research team reports how, when life on Earth became so big
In 3.5 billion years, life on earth went from single microscopic cells to giant sequoias and blue whales. Scientists have now documented quantitatively that the increase in maximum size of organisms was not gradual, but happened in two distinct bursts "tied to the geological evolution of the planet," said Michal Kowalewski, professor of geosciences at Virginia Tech.
Snails and humans use same genes to tell right from left
Biologists have tracked down genes that control the handedness of snail shells, and they turn out to be similar to the genes used by humans to set up the left and right sides of the body.
CSHL scientists discover new way in which ubiquitin modifies transcriptional machinery to regulate gene activity
During gene transcription - the process inside the nucleus of cells by which DNA, the genetic material, is copied into RNA - a large, ever-changing multiprotein complex is enlisted to assist the DNA-copying enzyme in its challenging job.
No quick or easy technological fix for climate change, researchers say
Global warming, some have argued, can be reversed with a large-scale "geoengineering" fix, such as having a giant blimp spray liquefied sulfur dioxide in the stratosphere or building tens of millions of chemical filter systems in the atmosphere to filter out carbon dioxide.
More Evolution Current Events and Evolution News Articles
 | Why Evolution Is True by Jerry A. Coyne Why evolution is more than just a theory: it is a factIn all the current highly publicized debates about creationism and its descendant “intelligent design,” there is an element of the controversy that is rarely mentioned—the evidence, the empirical truth of evolution by natural selection. Even Richard Dawkins and Stephen Jay Gould, while extolling the beauty of evolution and examining case... |
| Dr. Gundry's Diet Evolution: Turn Off the Genes That Are Killing You and Your Waistline by Steven R. Dr Gundry YOUR GENES ARE TRYING TO KILL YOU– AND YOU’RE EATING IT UP!Does losing weight and staying healthy feel like a battle? Well, it’s really a war. Your enemies are your own genes, backed by millions of years of evolution, and the only way to win is to outsmart them.Dr. Steven Gundry explains what your body is “thinking” and tells you why, surprisingly, your genes actually “want” you to... | |
 | Thank God for Evolution: How the Marriage of Science and Religion Will Transform Your Life and Our World by Michael Dowd Abridged CDs • 8 CDs, 9 hours A revolutionary perspective on the relationship between religion and science that builds a bridge between people of all... |
 | Evolution by Douglas J. Futuyma In its scope and emphases, Evolution is a readily recognized descendant of the author's previous textbook, Evolutionary Biology. However, it is much shorter and is exclusively directed toward an undergraduate audience. Teachers and students will find the list of important concepts and terms in each chapter a helpful guide, and will appreciate the radically different dynamic figures and lively... |
 | Evolution for Everyone: How Darwin's Theory Can Change the Way We Think About Our Lives by David Sloan Wilson What is the biological reason for gossip?For laughter? For the creation of art?Why do dogs have curly tails?What can microbes tell us about morality?These and many other questions are tackled by renowned evolutionist David Sloan Wilson in this witty and groundbreaking new book. With stories that entertain as much as they inform, Wilson outlines the basic principles of evolution and shows how,... |
 | Evolution: What the Fossils Say and Why It Matters by Donald R. Prothero Over the past twenty years, paleontologists have made tremendous fossil discoveries, including fossils that mark the growth of whales, manatees, and seals from land mammals and the origins of elephants, horses, and rhinos. Today there exists an amazing diversity of fossil humans, suggesting we walked upright long before we acquired large brains, and new evidence from molecules that enable... |
 | The Edge of Evolution: The Search for the Limits of Darwinism by Michael J. Behe When Michael J. Behe's first book, Darwin's Black Box, was published in 1996, it launched the intelligent design movement. Critics howled, yet hundreds of thousands of readers -- and a growing number of scientists -- were intrigued by Behe's claim that Darwinism could not explain the complex machinery of the cell.Now, in his long-awaited follow-up, Behe presents far more than a challenge to... |
 | Radical Evolution: The Promise and Peril of Enhancing Our Minds, Our Bodies -- and What It Means to Be Human by Joel Garreau Taking us behind the scenes with today’s foremost researchers and pioneers, bestselling author Joel Garreau shows that we are at a turning point in history. At this moment we are engineering the next stage of human evolution. Through advances in genetic, robotic, information, and nanotechnologies, we are altering our minds, our memories, our metabolisms, our personalities, our progeny–and... |
 | Only a Theory: Evolution and the Battle for America's Soul by Kenneth R. Miller A leading scientist examines the battle between evolution and Intelligent Design in America At the dawn of the twenty- first century, the debate over Darwin’s theory of evolution is nearly as contentious as it was in the notorious Scopes trial a century ago. Today, however, people who believe that evolution is “only a theory” have put their hopes in a concept known as Intelligent Design. In... |
 | An Introduction to Biological Evolution by Kenneth V. Kardong Written for a general college audience, this book offers an introduction to the principles and significance of Darwinian evolution. It differs from most other textbooks on evolution in three fundamental ways: First, it is intended for students taking evolution early in their studies. Second, it examines the intellectual significance of Darwinian evolution. Third, the text departs from the... |
| © 2009 BrightSurf.com |