Latest news with #CurrentBiology
Yahoo
3 hours ago
- General
- Yahoo
The Maya Civilization Collapsed 1,200 Years Ago. But Their Genes Never Stopped Spreading.
Here's what you'll learn when you read this story: A new study uses genome analysis to show the decline, not erasure, of the ancient Maya civilization. Researchers compared the genomes of seven skeletons to previously sequenced sets from across Siberia and the Americas, and showed strong genetic continuity from ancient to contemporary Maya people. Time-stamped genomes revealed a population increase peaking around 730 A.D. (likely thanks to the emergence of maize agriculture), and a subsequent decline in 750 A.D. (directly coinciding with the collapse of Maya civilization). The ancient Maya were a group of Mesoamerican Indigenous people who developed one of the most advanced societies in history, which such achievements as a complex written language and amazingly accurate calendar systems. One of the thriving capitals of Maya civilization was Copán—a city in modern-day Honduras that acted as a travel hub between Central and South America. A new study analyzing skeletons buried near Copán reveals the collapse, but not total erasure, of the Maya civilization over 1,200 years ago. 'Our findings indicate a decline in population size,' Shigeki Nakagome, a co-author of the study, told Live Science, that 'aligns with a scenario proposed by archaeologists in which the population decreased but did not become entirely extinct.' Published on May 28 in the journal Current Biology, the study included analysis of the genomes of seven individuals from the Classic Maya period—or the period in which Maya civilization experienced destabilization and eventual collapse—to investigate the hypothesis that Copán was ruled by outsiders. Inscriptions previously found in Copán suggest the first ruler of the dynasty, K'inich Yax K'uk' Mo', was an outsider who assumed power in 426 B.C. The theory suggests that a network of Maya elites migrated to the region and married with the local, non-Maya population, creating immense social change. Previous studies analyzing tooth enamel support the migration hypothesis. Researchers found that each of the seven individuals had different marriage lineages. Two of the people—one a possible member of the ruling dynasty, and the other a victim of human sacrifice—belonged to the same Y-chromosome haplogroup. A haplogroup is a population that has the same genetic markers passed down by a common ancestor. However (though this seems remarkable), it doesn't mean that the two individuals were closely related. 'Even though the dynastic ruler and the sacrificed individual share the same Y-chromosome haplogroup,' Nakagome told Live Science, 'we did not find any kinship.' On top of comparing the individuals' genomes to each other, researchers also compared the sets with previously sequenced genomes from across the Americas and Siberia. The scientists found strong evidence of genetic continuity between ancient and modern Maya people, suggesting 'the enduring persistence of local ancestry in the Maya region,' according to the study. Researchers also found an influx of people with ancestry from highland Mexican populations extant during the early to mid-Classic period. These outsiders could have been part of the dynasty of Copán. Finally, researchers used time-stamped genomes to estimate population sizes at different points in time. The study determined that Maya society saw a sharp increase in population that peaked around 730 A.D. at 19,000 people. According to researchers, the spike likely occurred thanks to the emergence of maize agriculture. Researchers saw a subsequent decline in population around 750 A.D., 'coinciding with the onset of the collapse of Classic Maya civilization,' according to the paper. The scientists on the study juggled many questions while conducting their research, which ultimately furthers our understanding of both the ancient and contemporary Maya people. '[O]ur research offers a new perspective, suggesting the enduring persistence of local ancestry in the Maya region,' the researchers wrote, 'while also highlighting the broader mobility beyond the conventional boundaries of the Maya territory.' You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
Time of India
2 days ago
- Science
- Time of India
Shocking! 183-million-year-old Dinosaur-era sea creature found with skin and scales intact
In a discovery that's catching the attention of scientists, researchers have found a remarkably well-preserved fossil of a marine reptile that's challenging what we thought we knew about how these creatures lived. The fossil, identified as Plesiopterys wildi, is around 183 million years old and was uncovered in southern Germany. What makes it especially rare is the presence of preserved soft tissues, like skin, scales, and keratin, which are almost never found in marine reptiles from the Jurassic period. The findings, published in Current Biology, offer a rare and detailed look at the texture, colouring, and movement of plesiosaurs– long-necked marine reptiles that lived during the Mesozoic era. Until now, scientists had to rely mostly on bones to imagine what these animals looked like, but this discovery gives a much clearer picture. Fossil found in 1940, but only studied recently The fossil specimen, labelled MH 7, was originally discovered in 1940 near Holzmaden, a region known for its fossil-rich Posidonia Shale. However, the specimen remained unprepared for decades. It was only in 2020 that researchers began to remove the surrounding limestone carefully and realised the fossil contained patches of soft tissue. by Taboola by Taboola Sponsored Links Sponsored Links Promoted Links Promoted Links You May Like American Investor Warren Buffett Recommends: 5 Books For Turning Your Life Around Blinkist: Warren Buffett's Reading List Undo 'Fossilized soft tissue, such as skin and internal organs, is exceptionally rare. We used a broad range of techniques to identify smooth skin in the tail region as well as scales along the rear edge of the flippers. This provided us with unparalleled insights into the appearance and biology of these long-extinct reptiles,' says Miguel Marx, a PhD student at Lund University and the study's lead author, as quoted by Lund University. Flippers show signs of specialised movement When researchers examined the fossil under a microscope, they found that the flippers were covered with tiny, triangular scales made of beta-keratin—a tough protein found in reptiles. These sturdy flippers likely helped the animal move with precision and control underwater. On the other hand, the skin on the tail was smoother and made of alpha-keratin, suggesting it had a different function. This difference in texture shows that various parts of the body were specially adapted for different roles in swimming and steering. 'Apart from the mosaic of smooth skin and scales, it was an incredible moment to visualize the cells in thin sections of the fossilized plesiosaur's skin. I was shocked when I saw skin cells that had been preserved for 183 million years. It was almost like looking at modern skin,' says Marx, as quoted by Lund University. Traces of pigment suggest patterned colouring One of the more unexpected findings was the discovery of melanosomes– tiny structures that carry pigment– in the skin of the tail. This suggests that the animal may have had patterns or variations in skin colour, instead of the plain or pale look that scientists usually imagine for marine reptiles. The researchers noted that this pigmentation could have played a role in camouflage or communication, though further analysis would be needed to confirm such functions. Discovery of a tail fin adds new clues Along with the preserved skin and scales, researchers also found a soft-tissue tail fin– something rarely seen in plesiosaur fossils. This broad and flexible structure suggests the tail may have helped the animal steer more effectively or even boosted its speed while swimming. Exceptional preservation thanks to Posidonia Shale The exceptional condition of the fossil is thanks to the unique environment where it was preserved. The Posidonia Shale– an ancient seabed with very low oxygen levels– slows down the process of decay, sometimes allowing soft tissues to fossilise along with bones. This kind of preservation is extremely rare in marine reptiles, which makes MH 7 a remarkable find and an important discovery for paleontologists. Adding detail to the story of Plesiosaur evolution Most studies on plesiosaurs have focused only on their bones, but this fossil gives a much fuller picture of the animal's biology. The preserved soft tissues offer new insights into how different parts of its body worked and how these features may have evolved over time. According to the research team, these findings may also contribute to understanding how plesiosaurs adapted to specific environments over time. 'Our findings help us create more accurate life reconstructions of plesiosaurs, something that has been extremely difficult since they were first studied over 200 years ago. Also, the well-preserved German fossil really highlights the potential for soft tissue in providing valuable insights into the biology of these long-extinct animals,' explains Marx, as quoted by Lund University. After sitting untouched for nearly 80 years, this discovery is now offering one of the most detailed views yet into the biology of a creature that swam the Earth's oceans almost 200 million years ago. The MH 7 fossil not only deepens our understanding of plesiosaurs but also highlights how valuable it can be to revisit and study old, forgotten specimens. Thumb image credit: X/@JoschuaKnuppe (Illustration of "Skin, scales, and cells in a Jurassic plesiosaur")
Yahoo
5 days ago
- Health
- Yahoo
A quiet island experiment reveals a battle of the bees
Since 2018, honeybees have feasted on wildflowers across a remote Italian island called Giannutri every spring. But for the last four years, Lorenzo Pasquali had the unusual task of shutting the honeybee hives down and watching wild bees as they scrambled to claim the flowers, racing for every drop of nectar in the absence of their domesticated rivals. Managed honeybees, often used in agriculture, and native bees feast on the same floral nectars and pollens. Ecologists have long suspected that honeybees may be pushing wild bees to the margins, but carrying out experiments in these wild insects has turned out to be tricky. Pasquali, an ecologist now at the University of Bialystok, Poland, and his colleagues turned the islet—just over half the size of New York's Central Park—into a living laboratory to test honeybees' impact. The results, recently published in the journal Current Biology, suggest that wild bee numbers alarmingly dropped. With the temporary removal of honeybees, nectar and pollen levels surged, allowing wild bees to forage more and feed on nectar longer and altering their daily routines. 'It is surprising and a nice experiment,' says Alfredo Valido, an entomologist at the Instituto de Productos Naturales y Agrobiología in Spain, who was not involved in the research. The researchers designed a very clear experiment relating honeybees, flowers and wild bees, he adds. (Native bees that pollinate many of our favorite foods.) Beekeepers first brought honeybee queens to Giannutri to raise them in isolation. The island is part of the Tuscan Archipelago National Park, and in 2021, authorities asked Pasquali's advisor, entomologist Leonardo Dapporto of the University of Florence to investigate whether managed honeybees that were recently brought to the island might have an unexpected ecological fallout. Hiking the island with another colleague, Alessandro Cini of the University of Pisa, they noticed plenty of honeybees buzzing around, but just a few wild bees. 'What if tomorrow there are no honeybees on the island?' Dapporto wondered. 'How [would] the behavior of wild bees change?' The team decided to use the island as a natural experiment. Every other morning, Pasquali would seal off the entrances to all 18 honeybee hives on alternating mornings, making sure the honeybees couldn't leave. Then, he and fellow researchers would observe the island's wild pollinators. The bees were kept inside until late afternoon—just long enough for researchers to observe how wild bees behaved in their absence. 'It was a unique experience. Never boring,' Pasquali says. 'I still remember every plant and rock on the island.' For Pasquali and his teammates, identifying native wild bees was easy. The wild bees are bigger and darker with bright colors. The wild bees also fly with a distinct buzzing sound compared to the honeybees. The researchers tracked how often wild bees entered or exited plots of land, tracking how often they visited flowers, and how long they spent drinking nectar. Using delicate tubes, they also measured the volume of nectar available for the wild bees in presence or absence of honeybees. The team found that when honeybees were locked in their hives, nectar volume increased by over 50 percent in some plants, while pollen level spiked by nearly 30 percent. Subsequently, the researchers found an increased level of searching behavior in wild bees and they also sucked in nectar for a longer time. Over four years, as the team carried out surveys on the island to monitor wild bee populations, they found that Anthophora dispar, a solitary native bee species, and Bombus terrestris, a type of bumblebee, fell by nearly 80 percent compared to their population level at the start of the study in 2021. While in the beginning of the experiment researchers expected to see some impacts to the wild bees, 'we didn't imagine that the impact was this strong,' Dapporto says. The dataset is still a correlation, he adds, but the fact that the wild bee population declined so significantly after the introduction of honeybees puts them on the prime focus compared to other factors. (There are thousands of species of wild bee species—and many are disappearing.) 'We are not against beekeeping practice,' Dapporto adds. But when honeybees are introduced into protected areas, especially those home to rare, endangered, or native wild bee species, park authorities should exercise great caution and ecological assessment. Wild bees on bigger islands and even in sensitive protected areas in mainland regions might be facing similar fates, if honeybees have been introduced without proper assessment, the team says. Wild bees face a range of threats, from habitat loss and climate change to pesticide exposure. But unlike many of these pressures, competition from honeybees is something humans can actively manage. As soon as Dapporto's team informed the national park about the results, the park immediately took action, halting the practice of beekeeping starting this year. That makes the results even more impressive, Valido says, commending the quick action. 'It's not logical to introduce [managed species] in an area where you want to preserve the flora and fauna,' he adds. In addition to beekeeping, 'sometimes conservation areas have a variety of land uses for things like pasture cattle and sheep,' says Victoria Wojcik, Science Director at the Pollinator Partnership Canada, a non-profit dedicated for the conservation of pollinators. Even in these cases, conservationists should look at the ecosystem resources to avoid overstocking. But for an area designated as a critical habitat for an invertebrate species, specifically a bee, 'I would be really confused as to why someone would consider permitting honeybee keeping in that landscape,' she adds. As for Dapporto and his team, they are continuing to track whether the native wild bees would change their behavior and bounce back in number as the honeybees are removed from the island. The team has already collected some data this year and is planning to continue observation for coming years. 'Then we could see if a longer absence of honeybees will produce a [major] effect on the behavior of wild bees,' he adds.
National Geographic
5 days ago
- Science
- National Geographic
A quiet island experiment reveals a battle of the bees
When beekeepers introduced honeybees to a protected island, wild bees nearly vanished. Could removing the hives reverse the damage? Domestic honeybees (Apis mellifera) help with pollinating crops worldwide, but they also compete with wild bees for nectar resources. Photograph by Ingo Arndt, Nat Geo Image Collection Since 2018, honeybees have feasted on wildflowers across a remote Italian island called Giannutri every spring. But for the last four years, Lorenzo Pasquali had the unusual task of shutting the honeybee hives down and watching wild bees as they scrambled to claim the flowers, racing for every drop of nectar in the absence of their domesticated rivals. Managed honeybees, often used in agriculture, and native bees feast on the same floral nectars and pollens. Ecologists have long suspected that honeybees may be pushing wild bees to the margins, but carrying out experiments in these wild insects has turned out to be tricky. Pasquali, an ecologist now at the University of Bialystok, Poland, and his colleagues turned the islet—just over half the size of New York's Central Park—into a living laboratory to test honeybees' impact. The results, recently published in the journal Current Biology, suggest that wild bee numbers alarmingly dropped. With the temporary removal of honeybees, nectar and pollen levels surged, allowing wild bees to forage more and feed on nectar longer and altering their daily routines. 'It is surprising and a nice experiment,' says Alfredo Valido, an entomologist at the Instituto de Productos Naturales y Agrobiología in Spain, who was not involved in the research. The researchers designed a very clear experiment relating honeybees, flowers and wild bees, he adds. (Native bees that pollinate many of our favorite foods.) A new honeybee (Apis mellifera) emerges from a brood cell to live for six short weeks. It spends that time foraging for food, making honey, and raising the next generation. Composite Photograph by Anand Varma, Nat Geo Image Collection The buff-tailed bumblebee (Bombus terrestris) was one of two wild species that saw a drop in numbers on Giannutri Island after honeybees were introduced. Photograph by Chris Gomersall, 2020VISION/Nature Picture Library Beekeepers first brought honeybee queens to Giannutri to raise them in isolation. The island is part of the Tuscan Archipelago National Park, and in 2021, authorities asked Pasquali's advisor, entomologist Leonardo Dapporto of the University of Florence to investigate whether managed honeybees that were recently brought to the island might have an unexpected ecological fallout. Hiking the island with another colleague, Alessandro Cini of the University of Pisa, they noticed plenty of honeybees buzzing around, but just a few wild bees. From scuba diving to set-jetting 'What if tomorrow there are no honeybees on the island?' Dapporto wondered. 'How [would] the behavior of wild bees change?' The team decided to use the island as a natural experiment. Every other morning, Pasquali would seal off the entrances to all 18 honeybee hives on alternating mornings, making sure the honeybees couldn't leave. Then, he and fellow researchers would observe the island's wild pollinators. The bees were kept inside until late afternoon—just long enough for researchers to observe how wild bees behaved in their absence. 'It was a unique experience. Never boring,' Pasquali says. 'I still remember every plant and rock on the island.' For Pasquali and his teammates, identifying native wild bees was easy. The wild bees are bigger and darker with bright colors. The wild bees also fly with a distinct buzzing sound compared to the honeybees. The researchers tracked how often wild bees entered or exited plots of land, tracking how often they visited flowers, and how long they spent drinking nectar. Using delicate tubes, they also measured the volume of nectar available for the wild bees in presence or absence of honeybees. The team found that when honeybees were locked in their hives, nectar volume increased by over 50 percent in some plants, while pollen level spiked by nearly 30 percent. Subsequently, the researchers found an increased level of searching behavior in wild bees and they also sucked in nectar for a longer time. Over four years, as the team carried out surveys on the island to monitor wild bee populations, they found that Anthophora dispar, a solitary native bee species, and Bombus terrestris, a type of bumblebee, fell by nearly 80 percent compared to their population level at the start of the study in 2021. While in the beginning of the experiment researchers expected to see some impacts to the wild bees, 'we didn't imagine that the impact was this strong,' Dapporto says. The dataset is still a correlation, he adds, but the fact that the wild bee population declined so significantly after the introduction of honeybees puts them on the prime focus compared to other factors. Commercial beekeeping, like this operation on a ranch in California, is extremely important for agriculture, but honeybees may threaten native wild species when they're introduced to protected areas. Photograph by Anand Varma, Nat Geo Image Collection 'We are not against beekeeping practice,' Dapporto adds. But when honeybees are introduced into protected areas, especially those home to rare, endangered, or native wild bee species, park authorities should exercise great caution and ecological assessment. Wild bees on bigger islands and even in sensitive protected areas in mainland regions might be facing similar fates, if honeybees have been introduced without proper assessment, the team says. Wild bees face a range of threats, from habitat loss and climate change to pesticide exposure. But unlike many of these pressures, competition from honeybees is something humans can actively manage. As soon as Dapporto's team informed the national park about the results, the park immediately took action, halting the practice of beekeeping starting this year. That makes the results even more impressive, Valido says, commending the quick action. 'It's not logical to introduce [managed species] in an area where you want to preserve the flora and fauna,' he adds. In addition to beekeeping, 'sometimes conservation areas have a variety of land uses for things like pasture cattle and sheep,' says Victoria Wojcik, Science Director at the Pollinator Partnership Canada, a non-profit dedicated for the conservation of pollinators. Even in these cases, conservationists should look at the ecosystem resources to avoid overstocking. But for an area designated as a critical habitat for an invertebrate species, specifically a bee, 'I would be really confused as to why someone would consider permitting honeybee keeping in that landscape,' she adds. As for Dapporto and his team, they are continuing to track whether the native wild bees would change their behavior and bounce back in number as the honeybees are removed from the island. The team has already collected some data this year and is planning to continue observation for coming years. 'Then we could see if a longer absence of honeybees will produce a [major] effect on the behavior of wild bees,' he adds.
Yomiuri Shimbun
5 days ago
- Science
- Yomiuri Shimbun
Japan Team: Gene Decides Calico Cat Color Patterns
Courtesy of Hiroyuki Sasaki / Jiji Press A calico cat and Prof. Hiroyuki Sasaki TOKYO (Jiji Press) — A Japanese research team led by Kyushu University Prof. Hiroyuki Sasaki said it has discovered a gene that determines the color patterns of the tricolored calico cat, known in Japan as 'mike neko.' The team found that the coloring was decided by the ARHGAP36 gene on the X chromosome. The orange coloration reflects a missing portion of this gene, while the black fur color is due to the absence of such a deletion, the team said. The team's findings were published in the online edition of the U.S. journal Current Biology on May 15. It was established some 120 years ago that almost all calico cats are female and that the color-deciding factor was in the X chromosomes. About 60 years later, researchers discovered that one of the two X chromosomes is inactivate in calico cats. But the gene responsible for the distinct coloration long remained unidentified. 'As a dog and cat lover, I couldn't let this long-standing mystery go unsolved,' Sasaki said. He said that some of the team's research costs were obtained through crowdfunding between 2022 and 2023, raising over ¥10 million from 600 people. 'I think that there is no doubt (that ARHGAP36 is behind the coloration) as a research team from Stanford University in the United States also identified the same gene and is announcing it at the same time as us,' he said. Sasaki's team, which includes members from Kyushu University, the National Institute of Genetics, Azabu University and Kindai University, extracted and analyzed DNA from cats of many different colors, with the help from an animal hospital in Fukuoka in the Kyushu southwestern region. The team also examined data on cat DNA made available by the University of Missouri before discovering the ARHGAP36 gene. The team said that a deletion of about 5,000 base pairs of the ARHGAP36 gene on the active one of the X chromosomes results in the production of pheomelanin, which is orange in color, while the gene without such a deletion creates the black pigment eumelanin. Courtesy of Hiroyuki Sasaki / Jiji Press A calico cat, left, and a tortoiseshell cat are seen in this combination photo. Like calico cats, tortoiseshell cats, or 'sabi neko,' are mostly female. Tortoiseshell cats also share the same coloring phenomenon. Orange cats are mainly male, possessing one X chromosome and one Y chromosome. Their orange coloration, too, is due to the ARHGAP36 gene deletion on the X chromosome. The rare male calico cats have one extra chromosome, possessing two X chromosomes and one Y chromosome. The white coloration in cats, however, is not the ARHGAP36 gene's doings but is caused by a different gene. Domestic cats are descendants of the African wildcat that were domesticated by about 10,000 years ago. Similar to a brown tabby cat, the African wildcat has brown-black striped fur. The team suggested that it may be able to pinpoint when the ARHGAP36 gene deletion happened by assessing mummies and pictures of ancient cats.
