Tomatoes in The Galapagos Islands Appear to Be Evolving in Reverse
A newly documented example of wild growing tomatoes on the black rocks of the Galapagos Islands gives researchers a prime example of a species adapting by rolling back genetic changes put in place over several million years.
Researchers from the University of California, Riverside (UC Riverside) and the Weizmann Institute of Science in Israel say it's evidence that species can wind back changes that have happened through evolution.
Related:
"It's not something we usually expect," says molecular biochemist Adam Jozwiak, from UC Riverside. "But here it is, happening in real time, on a volcanic island."
Through an analysis of 56 tomato samples taken from the Galapagos, covering both the Solanum cheesmaniae and Solanum galapagense species, the team looked at the production of alkaloids in the plants: toxic chemicals intended to put off predators.
In the case of the S. cheesmaniae tomatoes, different alkaloids were found in different parts of the islands. On the eastern islands, the plants come with alkaloids in a form comparable to those in the cultivated fruit from the rest of the world; but to the west, an older, more ancestral form of the chemicals were found.
This older version of the alkaloid matches the one found in eggplant relatives of the tomato stretching back millions of years.
Through further lab tests and modeling, the researchers identified a particular enzyme as being responsible for this alkaloid production and confirmed its ancient roots. A change in just a few amino acids was enough to flip the switch on the alkaloid production, the researchers determined.
There are other isolated examples of evolutionary backflips known scientifically as genetic atavisms, where a mutation causes a species to revert to expressing an ancestral trait. These include experiments on chickens that have been genetically tweaked to revive their ancient programming for growing teeth.
The difference in this case is a critical change has propagated through entire populations. In some plants, multiple genes have reverted, suggesting strong selection pressures are involved.
What makes it an even more interesting shift is that the western parts of the Galapagos islands are younger – less than half a million years old – and more barren. It seems environmental pressures may have driven these steps back into evolutionary history.
Besides being a fascinating example of how evolution turns around on itself, the research also opens up possibilities for advanced genetic engineering that works with even greater control, altering plant chemistry for multiple benefits.
"If you change just a few amino acids, you can get a completely different molecule," says Jozwiak. "That knowledge could help us engineer new medicines, design better pest resistance, or even make less toxic produce."
"But first, we have to understand how nature does it. This study is one step toward that."
The research has been published in Nature Communications.
Earth Became a Hothouse 250 Million Years Ago, And We Finally Know Why
Scientists Find Most Cats Sleep on Their Left Side – This Could Be Why
Orcas Caught 'Kissing' For Two Minutes With Tongue
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Yahoo
a day ago
- Yahoo
Tomatoes in The Galapagos Islands Appear to Be Evolving in Reverse
The idea of evolution backtracking isn't a completely new idea, but catching it in action isn't an everyday experience. A newly documented example of wild growing tomatoes on the black rocks of the Galapagos Islands gives researchers a prime example of a species adapting by rolling back genetic changes put in place over several million years. Researchers from the University of California, Riverside (UC Riverside) and the Weizmann Institute of Science in Israel say it's evidence that species can wind back changes that have happened through evolution. Related: "It's not something we usually expect," says molecular biochemist Adam Jozwiak, from UC Riverside. "But here it is, happening in real time, on a volcanic island." Through an analysis of 56 tomato samples taken from the Galapagos, covering both the Solanum cheesmaniae and Solanum galapagense species, the team looked at the production of alkaloids in the plants: toxic chemicals intended to put off predators. In the case of the S. cheesmaniae tomatoes, different alkaloids were found in different parts of the islands. On the eastern islands, the plants come with alkaloids in a form comparable to those in the cultivated fruit from the rest of the world; but to the west, an older, more ancestral form of the chemicals were found. This older version of the alkaloid matches the one found in eggplant relatives of the tomato stretching back millions of years. Through further lab tests and modeling, the researchers identified a particular enzyme as being responsible for this alkaloid production and confirmed its ancient roots. A change in just a few amino acids was enough to flip the switch on the alkaloid production, the researchers determined. There are other isolated examples of evolutionary backflips known scientifically as genetic atavisms, where a mutation causes a species to revert to expressing an ancestral trait. These include experiments on chickens that have been genetically tweaked to revive their ancient programming for growing teeth. The difference in this case is a critical change has propagated through entire populations. In some plants, multiple genes have reverted, suggesting strong selection pressures are involved. What makes it an even more interesting shift is that the western parts of the Galapagos islands are younger – less than half a million years old – and more barren. It seems environmental pressures may have driven these steps back into evolutionary history. Besides being a fascinating example of how evolution turns around on itself, the research also opens up possibilities for advanced genetic engineering that works with even greater control, altering plant chemistry for multiple benefits. "If you change just a few amino acids, you can get a completely different molecule," says Jozwiak. "That knowledge could help us engineer new medicines, design better pest resistance, or even make less toxic produce." "But first, we have to understand how nature does it. This study is one step toward that." The research has been published in Nature Communications. Earth Became a Hothouse 250 Million Years Ago, And We Finally Know Why Scientists Find Most Cats Sleep on Their Left Side – This Could Be Why Orcas Caught 'Kissing' For Two Minutes With Tongue
Yahoo
3 days ago
- Yahoo
Astronomers Capture First-Ever Image of Star That Exploded Twice
For years, scientists have suspected that stars can meet their doom by a one-two punch of back-to-back explosions — but they've never seen visual evidence of this happening. That just changed. Astronomers using the Very Large Telescope in Chile have taken the first-ever image of a star that died in a stellar "double-detonation," leaving behind a spectacular supernova remnant. Their findings, published as a new study in the journal Nature Astronomy, deepen our understanding of the stellar evolution of burned-out stars called white dwarfs. "The explosions of white dwarfs play a crucial role in astronomy," lead author Priyam Das, a researcher at the University of New South Wales Canberra, Australia, said in a statement about the work. "Yet, despite their importance, the long-standing puzzle of the exact mechanism triggering their explosion remains unsolved." Once an exceptionally massive star — one at least several times heavier than the Sun — burns through all its fuel, it collapses under its own gravity in a powerful explosion known as a supernova. That's just one way supernovas can happen, though, and not all of them end the same. Some result in the star being completely obliterated, but others, if the star is heavy enough, can produce a super dense core called a neutron star, or even a black hole. The scene imaged by the VLT is the work of what's called a Type Ia supernova, produced by a low-mass star that exhausted all its fuel and left behind a remnant called a white dwarf. These objects are more compact and far denser than their original stars, endowing them with a wicked gravitational pull. In binary systems, this powerful gravity can lead to the white dwarf stripping matter off its stellar companion if their orbits are close enough. When enough of this stolen material accumulates on the surface of the white dwarf, reaching a point known as critical mass, it kickstarts a single but incredibly destructive thermonuclear explosion that wipes out both stars. That's the typical understanding. More recent research, though, has found evidence that some white dwarfs are battered by two explosions, not one, prior to winking out. In this scenario, astronomers believe that a white dwarf is swimming in a cloud of siphoned helium. This unstable helium cloud is the first to explode, precipitating a second blast in the core of the star. And bam: you have a two-fer supernova. Critically, this type of supernova occurs before the white dwarf reaches critical mass. Astronomers predicted that this double-detonation would produce a unique, visual signature in the form of two separate shells of calcium — and the new image bears this out. If you look closely, you can see that the calcium, depicted in blue, is indeed in a two-shell arrangement. This is a "clear indication that white dwarfs can explode well before they reach the famous Chandrasekhar mass limit, and that the 'double-detonation' mechanism does indeed occur in nature," said coauthor Ivo Seitenzahl, who conducted the observations while at the Heidelberg Institute for Theoretical Studies in Germany, in the statement. The work is invaluable for another reason. Type Ia explosions are considered "standard candles" that astronomers use as a measuring stick in the cosmos, because they shine at a consistent luminosity. Now we understand a little more about why that's the case. "Revealing the inner workings of such a spectacular cosmic explosion is incredibly rewarding," Das said. More on stars: Scientists Working to Decode Signal From Earliest Years of Universe
Yahoo
5 days ago
- Yahoo
First complete ancient Egyptian DNA genome reveals his occupation
In 1985, geneticists achieved a major archeological breakthrough after they successfully extracted partial DNA from ancient Egyptian skeletal remains. Almost exactly four decades later, researchers have sequenced the first whole genome from an individual who lived amid the civilization's earliest eras. The findings are detailed in a study published July 2 in the journal Nature. Egyptologists have spent centuries analyzing mountains of archeological materials spanning thousands of years' worth of history. But while experts now know a fair amount about ancient Egyptian life, they still understand very little about the population's genetic makeup. Researchers have genomically analyzed three specimens to date, but in each case, poor DNA preservation resulted in only partial sequences. A tooth stored in museum archives for over a century has changed that, however. Archeologists initially excavated it (and its owner) around 1902 at Nuwayrat, a village roughly 165 miles south of Cairo. Experts couldn't immediately glean much from the body, but radiocarbon dating revealed the individual lived between 2855 and 2570 BCE. This placed him between the Early Dynastic and Old Kingdom periods, a time when rulers oversaw the first pyramid construction projects, but before standardized mummification practices. This lack of mummification likely contributed to the DNA's long-lasting integrity, allowing researchers from the Francis Crick Institute and Liverpool John Moores University in the United Kingdom to finally extract its full genomic information. Their genetic analysis linked 80 percent of his DNA to North Africa, while the remaining 20 percent traces to the Mesopotamian Fertile Crescent near present-day Iraq. It's still unclear if most Egyptians at that time shared a similar ancestry. However, the tooth's dietary chemical signatures indicate the man grew up in Egypt as opposed to migrating there. Further examinations of the overall skeleton also point to a life of hard labor. 'The markings on the skeleton are clues to the individual's life andlifestyle—his seat bones are expanded in size, his arms showed evidence of extensive movement back and forth, and there's substantial arthritis in just the right foot,' explained Liverpool John Moores University archeologist and study second author Joel Irish. Irish and colleagues believe the man likely worked as a potter, with the foot arthritis corresponding to the use of a pottery technology arrived in Egypt around the same time that he was alive. 'That said, his higher-class burial is not expected for a potter, who would not normally receive such treatment,' added Irish. 'Perhaps he was exceptionally skilled or successful [enough] to advance his social status.' Moving forward, the team hopes that their achievement is only the first of many similar DNA sequencing projects. 'Piecing together all the clues from this individual's DNA, bones and teeth have allowed us to build a comprehensive picture,' said study first author Adeline Morez Jacobs. 'We hope that future DNA samples from ancient Egypt can expand on when precisely this movement from West Asia started.'
