DNA detectives in Antarctica: probing 6,000 years of penguin poo for clues to the past

Jamie Wood, University of Adelaide and Theresa Cole, University of AdelaideStudies of ancient DNA have tended to focus on frozen land in the northern hemisphere, where woolly mammoths and bison roamed. Meanwhile, Antarctica has received relatively little attention. We set out to change that. The most suitable sediments are exposed near the coast of the icy continent, where penguins like to breed. Their poo is a rich source of DNA, providing information about the health of the population as well as what penguins have been eating. Our new research opens a window on the past of Adélie penguins in Antarctica, going back 6,000 years. It also offers a surprise glimpse into the shrinking world of southern elephant seals over the past 1,000 years. Understanding how these species coped with climate change in the past can help us prepare for the future. Wildlife in Antarctica faces multiple emerging threats and will likely need support to cope with the many challenges ahead. A unique marine ecosystem Adélie penguins are particularly sensitive to changes in their environment. This makes them what we call a “sentinel species”, providing an early warning of imbalance or dysfunction in the coastal ecosystem. Their poo also provides a record of how they responded to changes in the past. In our new research, we excavated pits up to 80cm...
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World’s Largest Genome Discovered in a Tiny Fern: ‘Breaks all records’

A group of small fork ferns – credit Pol Fernandez, released via iScienceOn the island of New Caledonia, a simple, unassuming species of fern has been identified as having the longest genome of any living organism known.It is 50 times longer than a human’s, 7% longer than the previous world record-holding species for longest genome, and 20% longer than the record-holding animal.Compared to 23 pairs of chromosomes in every human cell, the tiny fern contains 416—and if unraveled, would climb higher than Big Ben in London’s Westminster.Questions abound, as does admiration for the majesty and mysteries of biological life.“Compared to other organisms, plants are incredibly diverse when viewed at the DNA level, and that should make us pause to think about their intrinsic value in the wider picture of global biodiversity,” said Dr. Ilia Leitch, Senior Research Leader at the Royal Botanical Gardens, Kew.“This discovery also raises many new and exciting questions about the upper limits of what is biologically possible, and we hope to solve these mysteries one day.”Tmesipteris oblanceolata is a species of New Caledonian fork fern that grows on the ground or out of rotting tree trunks. A team from Kew and the Institut Botànic de Barcelona traveled to New Caledoina’s largest island of Grand Terre to collect this species for study.20,000 species...
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Leading a new era in ancient DNA research

A new ancient DNA lab at Emory is mapping little-explored human lineages, studying genetics of the deep past to better understand modern-day populations of the Americas. Emory junior Rosseirys "Ro" De La Rosa is helping analyze DNA that she extracted from ancient bones unearthed in Uruguay — the remains of an Indigenous people known as the Charrúa. “Very few remains of the Charrúa have been found,” De La Rosa says. “They were largely wiped out by colonialism and a lot of mystery surrounds them. Anything that we can learn is important.” It may be possible to connect the ancient Charrúa to modern-day populations unaware of their link. “Culture matters,” says De La Rosa, who is continuing to work on the project remotely this semester. “Leaning about your own culture gives you a sense of unity and connection that you can pass down to others.” De La Rosa is a member of the Lindo Ancient DNA Laboratory, headed by John Lindo, Emory assistant professor of anthropology. The state-of-the-art facility, funded by major grants from National Geographic Explorer and the National Science Foundation, opened in January in Emory's Psychology and Interdisciplinary Sciences Building. It is one of the few in the world involved in every step of the complex process of solving mysteries surrounding ancient remains. "We build projects from the ground up,"...
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The first high-res 3D images of DNA segments

Credit: Berkeley Lab First-of-their-kind images by researchers at Berkeley Lab could aid in the use of DNA to build nanoscale devices. An international team working at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has captured the first high-resolution 3-D images from individual double-helix DNA segments, attached at either end of gold nanoparticles. The images detail the flexible structure of the DNA segments, which appear as nanoscale "jump ropes". This unique imaging capability, pioneered by Berkeley Lab scientists, could aid in the use of DNA segments as building blocks for molecular devices that function as nanoscale drug-delivery systems, markers for biological research, and components for computer memory and electronic devices. It could also lead to images of disease-relevant proteins that have proven elusive for other imaging techniques, and of the assembly process that forms DNA from separate, individual strands. The shapes of the coiled DNA strands, which were sandwiched between polygon-shaped gold nanoparticles, were reconstructed in 3-D using a cutting-edge electron microscope technique called individual-particle electron tomography (IPET).  This was combined with a protein-staining process and sophisticated software that provided structural details down to a scale of just...
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Genes for longer and healthier life identified

From a 'haystack' of 40,000 genes in three different organisms, scientists have found genes that are involved in physical aging. If you influence only one of these genes, the healthy lifespan of laboratory animals is extended – and possibly that of humans, too. Driven by the quest for eternal youth, humankind has spent centuries obsessed with the question of how exactly it is that we age. With advancements in molecular genetics in recent decades, the search for genes involved in the aging process has greatly accelerated. Until now, this was mostly limited to genes of individual model organisms such as the C. elegans nematode, which revealed that around 1% of its genes could influence life expectancy. However, researchers have long assumed that such genes arose during the course of evolution and in all living beings whose cells preserved a nucleus – from yeast to humans. Researchers at ETH Zurich and the JenAge consortium in Germany have now systematically gone through the genomes of three different organisms in search of the genes associated with the aging process that are present in all three species – and thus, derived from a common ancestor. Although they are found in different organisms, these so-called orthologous genes are closely related to each other, and they are all found in humans, too. To detect them, researchers...
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