Tag Archives: #humans

Analysis of Famous Fossil Helps Unlock When Humans And Apes Diverged (Paleontology)

The USC-led study examined the shoulder assembly of Little Foot, an Australopithecus that lived more than 3 million years ago, and may have confirmed how our human ancestors used their arms.

A long-awaited, high-tech analysis of the upper body of famed fossil Little Foot opens a window to a pivotal period when human ancestors diverged from apes, new USC research shows.

Little Foot’s shoulder assembly proved key to interpreting an early branch of the human evolutionary tree. Scientists at the Keck School of Medicine of USC focused on its so-called pectoral girdle, which includes collarbones, shoulder blades and joints.

Although other parts of Little Foot, especially its legs, show humanlike traits for upright walking, the shoulder components are clearly apelike, supporting arms surprisingly well suited for suspending from branches or shimmying up and down trees rather than throwing a projectile or dangling astride the torso like humans.

The Little Foot fossil provides the best evidence yet of how human ancestors used their arms more than 3 million years ago, said Kristian J. Carlson, lead author of the study and associate professor of clinical integrative anatomical sciences at the Keck School of Medicine.

“Little Foot is the Rosetta stone for early human ancestors,” he said. “When we compare the shoulder assembly with living humans and apes, it shows that Little Foot’s shoulder was probably a good model of the shoulder of the common ancestor of humans and other African apes like chimpanzees and gorillas.”

Little Foot fossil continues to help researchers explore human evolution

The apelike characteristics will likely attract considerable intrigue as science teams around the world have been examining different parts of the skeleton to find clues to human origins. The USC-led study, which also involved researchers at the University of Wisconsin, the University of Liverpool and the University of the Witwatersrand in South Africa, among others, was published today in the Journal of Human Evolution.

The journal devoted a special issue to Little Foot analyses from a global research group, which looked at other parts of the creature’s skeleton. The process is somewhat akin to the story of blind men and the elephant, each examining one part in coordination with others to explain the whole of something that’s not fully understood.

The Little Foot fossil is a rare specimen because it’s a near-complete skeleton of an Australopithecus individual much older than most other human ancestors. The creature, probably an old female, stood about 4 feet tall with long legs suitable for bipedal motion when it lived some 3.67 million years ago. Called “Little Foot” because the first bones recovered consisted of a few small foot bones, the remains were discovered in a cave in South Africa in the 1990s. Researchers have spent years excavating it from its rock encasement and subjecting it to high-tech analysis.

While not as widely known as the Lucy skeleton, another Australopithecus individual unearthed in East Africa in the 1970s, Carlson said Little Foot is older and more complete. The USC-led research team zeroed in on the shoulder assemblies because Little Foot provides the oldest and most intact example of this anatomy ever found. Those bones provide telltale clues of how an animal moves. In human evolution, he said, these parts had to change form before our ancestors could live life free of trees, walk the open savannah and use their arms for functions other than supporting the weight of the individual.

Humans, apes shared skeletal similarities for longer than previously assumed

The scientists compared the creature’s shoulder parts to apes, hominins and humans. Little Foot was a creature adapted to living in trees because the pectoral girdle suggests a creature that climbed trees, hung below branches and used its hands overhead to support its weight.

For example, the scapula, or shoulder blade, has a big, high ridge to attach heavy muscles similar to gorillas and chimpanzees. The shoulder joint, where the humerus connects, sits at an oblique angle, useful for stabilizing the body and lessening tensile loads on shoulder ligaments when an ape hangs beneath branches. The shoulder also has a sturdy, apelike reinforcing structure, the ventral bar. And the collarbone has a distinctive S-shaped curve commonly found in apes.

Those conclusions mean that the structural similarities in the shoulder between humans and African apes are much more recent, and persisted much longer, than has been proposed, Carlson said.

“We see incontrovertible evidence in Little Foot that the arm of our ancestors at 3.67 million years ago was still being used to bear substantial weight during arboreal movements in trees for climbing or hanging beneath branches,” he said. “In fact, based on comparisons with living humans and apes, we propose that the shoulder morphology and function of Little Foot is a good model for that of the common ancestor of humans and chimpanzees 7 million to 8 million years ago.”

The scientists were able to achieve remarkably clear images of the fossils. That’s because the bones, painstakingly excavated for many years, are in good condition and uniquely complete. The scientists examined them using micro-CT scans, which can detect minute features on the surface of an object, peer deep inside a bone, measure the density of an object and generate a 3D model without harming the fossil.

USC professors in collaboration with the Natural History Museum of Los Angeles County host a formidable array of paleontologists, augmented by anatomical specialists at the Keck School of Medicine. The museum was not part of this study.

The study authors are Kristian J. Carlson of USC; David J. Green of Campbell University School of Osteopathic Medicine in North Carolina; Tea Jashashvili of the Keck School of Medicine; Travis R. Pickering of the University of Wisconsin, Madison; Jason L. Heaton of the Birmingham-Southern College, Birmingham, Alabama; Amélie Beaudet, Cambridge University, UK; Dominic Stratford, University of the Witwatersrand; Robin Crompton, University of Liverpool, UK; Kathleen Kuman, University of the Witwatersrand; Laurent Bruxelles, French National Centre for Scientific Research at Jean Jaurès University, Toulouse, France, the French National Institute for Preventive Archaeological Researches, Nîmes, France; and Ronald J. Clarke, University of the Witwatersrand.

The study was supported by, among others, USC; PAST; DSI-NRF (South Africa); the University of the Witwatersrand; the U.S. National Science Foundation (BCS-0824552); The L.S.B. Leakey Foundation; The Wenner-Gren Foundation; The Campbell University Jerry M. Wallace School of Osteopathic Medicine; Standard Bank; and JP Morgan Chase.

Featured image: The Little Foot skeleton was discovered in the 1990s in a cave in South Africa and is the most intact ancient skeleton of any human ancestor. (Photo/Paul John Myburgh, Courtesy of the University of the Witwatersrand, Johannesburg, South Africa)

Reference: Kristian J. Carlson, David J. Green, Tea Jashashvili, Travis R. Pickering, Jason L. Heaton, Amélie Beaudet, Dominic Stratford, Robin Crompton, Kathleen Kuman, Laurent Bruxelles, Ronald J. Clarke, The pectoral girdle of StW 573 (‘Little Foot’) and its implications for shoulder evolution in the Hominina, Journal of Human Evolution, 2021, 102983, ISSN 0047-2484, https://doi.org/10.1016/j.jhevol.2021.102983. (https://www.sciencedirect.com/science/article/pii/S004724842100035X)

Provided by USC news

The Chillest Ape: How Humans Evolved A Super-High Cooling Capacity (Biology)

Penn Medicine discovery illuminates human sweat gland evolution

Humans have a uniquely high density of sweat glands embedded in their skin—10 times the density of chimpanzees and macaques. Now, researchers at Penn Medicine have discovered how this distinctive, hyper-cooling trait evolved in the human genome. In a study published today in The Proceedings of the National Academy of Sciences of the USA, researchers showed that the higher density of sweat glands in humans is due, to a great extent, to accumulated changes in a regulatory region of DNA—called an enhancer region—that drives the expression of a sweat gland-building gene, explaining why humans are the sweatiest of the Great Apes.

“This is one of the clearest examples I’ve ever seen of pinpointing the genetic basis for one of the most extreme and distinctively human evolutionary traits as a whole,” said the study’s senior author, Yana Kamberov, PhD, an assistant professor of genetics at Penn Medicine. “This kind of research is important not only because it shows how evolution actually works to produce species diversity but also because it gives us access into human biology that is often not possible to gain in other ways, essentially by learning from tweaking the biological system in a way that is actually beneficial, without breaking it.”

Scientists broadly assume that humans’ high density of sweat glands, also called eccrine glands, reflects an ancient evolutionary adaptation. This adaptation, coupled with the loss of fur in early hominins, which promoted cooling through sweat evaporation, is thought to have made it easier for them to run, hunt, and otherwise survive on the hot and relatively treeless African savannah, a markedly different habitat than the jungles occupied by other ape species.

Kamberov found in a 2015 study that the expression level of a gene called Engrailed 1—EN1 in humans—helps determine the density of eccrine glands in mice. EN1 encodes a transcription factor protein that, among many other functions, works during development to induce immature skin cells to form eccrine glands. Because of this property, Kamberov and colleagues hypothesized that perhaps one way in which humans could have built more sweat glands in their skin is to evolve genetic changes that increased the production of EN1 in the skin.

The activity of a gene is often affected by nearby regions of DNA called enhancer regions, where factors that activate the gene can bind and help drive the gene’s expression. In the study, Kamberov and her team identified an enhancer region called hECE18 that boosts the production of EN1 in skin, to induce the formation of more eccrine glands. The researchers showed that the human version of hECE18 is more active than that of ape or macaque versions, which would in turn drive higher levels of EN1 production.

Kamberov and her colleagues also teased apart the individual mutations that distinguish human hECE18, showing why some of them boost EN1 expression—and showing that rolling back those mutations to the chimp version of hECE18 brings the enhancer activity down to chimp levels.

Prior studies of evolved human-specific traits, such as language, generally have tied such traits to complex genetic changes involving multiple genes and regulatory regions. In contrast, the work from Kamberov and her team suggest that the human “high-sweat” trait evolved at least in part through repeated mutations to just one regulatory region, hECE18. This means that this single regulatory element could have repeatedly contributed to a gradual evolution of higher eccrine gland density during human evolution.

While the study is mainly a feat of basic biology that shines a light on human evolution, it also should have some long-term medical relevance, Kamberov said.

“Severe wounds or burns often destroy sweat glands in skin, and so far we don’t know how to regenerate them—but this study brings us closer to discovering how to do that,” she said. “The next step in this research would be to uncover how the multiple activity enhancing mutations in hECE18 interact with each other to increase EN1 expression and to use these biologically key mutations as starting points to figure out what DNA-binding factors actually bind at these sites. Basically, this provides us with a direct molecular inroad to discover the upstream factors that by activating EN1 expression get skin cells to start making sweat glands.”

Support for the research was provided by the National Science Foundation (BCS-1847598) the National Institute of Arthritis and Musculoskeletal and Skin Diseases (R01AR077690), the McCabe Fund, the Penn Skin Biology and Disease Resource-based Center (P30AR069589), and the National Institute of Child Health and Human Development (F32HD101230).

Featured image: Over time, humans gradually evolved a stronger enhancer for activating Engrailed 1 gene expression, resulting in more sweat glands and making them the sweatiest of the Great Apes. © Penn Medicine

Reference: Daniel Aldea, Yuji Atsuta, Blerina Kokalari, Stephen F. Schaffner, Rexxi D. Prasasya, Adam Aharoni, Heather L. Dingwall, Bailey Warder, Yana G. Kamberov, “Repeated mutation of a developmental enhancer contributed to human thermoregulatory evolution”, Proceedings of the National Academy of Sciences Apr 2021, 118 (16) e2021722118; DOI: 10.1073/pnas.2021722118

Provided by Penn Medicine

Study of Mouse Gut Microbiome May Provide Clues to How Cancer Develops in Humans (Medicine)

A study of the mouse gut microbiome led by researchers from Mayo Clinic may shed light on how cancerous tumors develop and progress in humans. The findings will be presented this evening in a late-breaking abstract (#LB226) at the 2021 American Association for Cancer Research annual meeting.

“There is growing recognition that healthy tissues accumulate cancer-related mutations over time but they don’t necessarily cause illness,” says stem cell and cancer biologist Nagarajan Kannan, Ph.D., who led the study. “We asked the question, what would trigger these aberrant cells to grow uncontrollably and develop into a malignancy?”

Gastroenterologist Purna Kashyap, M.D., says the human gut contains large, diverse and self-sustaining microbes that are present in the trillions and contribute to our overall metabolism. “A bolus of microbes colonizes the gut at birth via transmission from mother to baby and are then constantly shaped by diet and lifestyle,” says Dr. Kashyap. “We believe there is great value in understanding how these microbes regulate processes within and outside the gut, to allow us to effectively harness their health benefits.”

“In our study we were able to show that oncogenic mammary cells behave differently in animals with and without germs,” says Dr. Kannan. “Cancer cells injected into ‘bubble mice’ (mice that are bred to have no germs) developed into early-onset, highly metastatic tumors,” he says. “However, when we injected these cells into regular laboratory mice, they developed into mostly late-onset, benign or poorly metastatic tumors.” 

Dr. Kannan says he and his colleagues were startled by these observations. They performed additional experiments where they colonized germ-free bubble mice with healthy germs, prepared from feces taken from healthy donor mice. “When these transplanted mice developed into adults, they developed late-onset, ‘poorly’ metastatic tumors,” says Dr. Kannan. “In many ways, the fate of transplanted mice and regular laboratory mice were similar, i.e,, they lived longer without any signs or symptoms of cancer,” he says. 

The study raises many important questions and challenges current thinking on how tumors develop and progress in humans. There is growing recognition that healthy tissues accumulate cancer-related mutations over time, but they don’t necessarily cause illness. “What triggers these aberrant cells to grow uncontrollably and develop malignancy is a question we are very interested in,” says Dr. Kannan.  “Understanding these earliest events in the pathogenesis of cancer may create opportunities for developing new paradigms in cancer prevention, both among individuals and within populations,” says Mark Sherman, M.D., a molecular pathologist and epidemiologist at Mayo Clinic.

Dr. Kannan says the findings open a new area of investigation in the pursuit of therapies to prevent and treat cancer. The germ-free bubble mice could play an important role in development of such innovative therapies. It is important to note that both human and mice guts are colonized by microbes at birth,” he says. “Therefore, what is true in mice may also be true in humans, and if that is so, then we may be forced to re-shape our thinking of cancer biology and how we design treatments for cancer.”

Provided by Mayo Clinic

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Humans Were Apex Predators For Two Million Years (Paleontology)

What did our ancestors eat during the stone age? Mostly meat

Researchers at Tel Aviv University were able to reconstruct the nutrition of stone age humans. In a paper published in the Yearbook of the American Physical Anthropology Association, Dr. Miki Ben-Dor and Prof. Ran Barkai of the Jacob M. Alkov Department of Archaeology at Tel Aviv University, together with Raphael Sirtoli of Portugal, show that humans were an apex predator for about two million years. Only the extinction of larger animals (megafauna) in various parts of the world, and the decline of animal food sources toward the end of the stone age, led humans to gradually increase the vegetable element in their nutrition, until finally they had no choice but to domesticate both plants and animals – and became farmers.

“So far, attempts to reconstruct the diet of stone-age humans were mostly based on comparisons to 20th century hunter-gatherer societies,” explains Dr. Ben-Dor. “This comparison is futile, however, because two million years ago hunter-gatherer societies could hunt and consume elephants and other large animals – while today’s hunter gatherers do not have access to such bounty. The entire ecosystem has changed, and conditions cannot be compared. We decided to use other methods to reconstruct the diet of stone-age humans: to examine the memory preserved in our own bodies, our metabolism, genetics and physical build. Human behavior changes rapidly, but evolution is slow. The body remembers.”

In a process unprecedented in its extent, Dr. Ben-Dor and his colleagues collected about 25 lines of evidence from about 400 scientific papers from different scientific disciplines, dealing with the focal question: Were stone-age humans specialized carnivores or were they generalist omnivores? Most evidence was found in research on current biology, namely genetics, metabolism, physiology and morphology.

The evolution of the HTL during the Pleistocene as they interpret it, based on the totality of the evidence. © Dr. Miki Ben Dor

“One prominent example is the acidity of the human stomach,” says Dr. Ben-Dor. “The acidity in our stomach is high when compared to omnivores and even to other predators. Producing and maintaining strong acidity require large amounts of energy, and its existence is evidence for consuming animal products. Strong acidity provides protection from harmful bacteria found in meat, and prehistoric humans, hunting large animals whose meat sufficed for days or even weeks, often consumed old meat containing large quantities of bacteria, and thus needed to maintain a high level of acidity. Another indication of being predators is the structure of the fat cells in our bodies. In the bodies of omnivores, fat is stored in a relatively small number of large fat cells, while in predators, including humans, it’s the other way around: we have a much larger number of smaller fat cells. Significant evidence for the evolution of humans as predators has also been found in our genome. For example, geneticists have concluded that “areas of the human genome were closed off to enable a fat-rich diet, while in chimpanzees, areas of the genome were opened to enable a sugar-rich diet.”

Evidence from human biology was supplemented by archaeological evidence. For instance, research on stable isotopes in the bones of prehistoric humans, as well as hunting practices unique to humans, show that humans specialized in hunting large and medium-sized animals with high fat content. Comparing humans to large social predators of today, all of whom hunt large animals and obtain more than 70% of their energy from animal sources, reinforced the conclusion that humans specialized in hunting large animals and were in fact hypercarnivores.

“Hunting large animals is not an afternoon hobby,” says Dr. Ben-Dor. “It requires a great deal of knowledge, and lions and hyenas attain these abilities after long years of learning. Clearly, the remains of large animals found in countless archaeological sites are the result of humans’ high expertise as hunters of large animals. Many researchers who study the extinction of the large animals agree that hunting by humans played a major role in this extinction – and there is no better proof of humans’ specialization in hunting large animals. Most probably, like in current-day predators, hunting itself was a focal human activity throughout most of human evolution. Other archaeological evidence – like the fact that specialized tools for obtaining and processing vegetable foods only appeared in the later stages of human evolution – also supports the centrality of large animals in the human diet, throughout most of human history.”

The multidisciplinary reconstruction conducted by TAU researchers for almost a decade proposes a complete change of paradigm in the understanding of human evolution. Contrary to the widespread hypothesis that humans owe their evolution and survival to their dietary flexibility, which allowed them to combine the hunting of animals with vegetable foods, the picture emerging here is of humans evolving mostly as predators of large animals.

“Archaeological evidence does not overlook the fact that stone-age humans also consumed plants,” adds Dr. Ben-Dor. “But according to the findings of this study plants only became a major component of the human diet toward the end of the era.”

Evidence of genetic changes and the appearance of unique stone tools for processing plants led the researchers to conclude that, starting about 85,000 years ago in Africa, and about 40,000 years ago in Europe and Asia, a gradual rise occurred in the consumption of plant foods as well as dietary diversity – in accordance with varying ecological conditions. This rise was accompanied by an increase in the local uniqueness of the stone tool culture, which is similar to the diversity of material cultures in 20th-century hunter-gatherer societies. In contrast, during the two million years when, according to the researchers, humans were apex predators, long periods of similarity and continuity were observed in stone tools, regardless of local ecological conditions.

Prof. Ran Barkai © Tel Aviv University

“Our study addresses a very great current controversy – both scientific and non-scientific,” says Prof. Barkai. “For many people today, the Paleolithic diet is a critical issue, not only with regard to the past, but also concerning the present and future. It is hard to convince a devout vegetarian that his/her ancestors were not vegetarians, and people tend to confuse personal beliefs with scientific reality. Our study is both multidisciplinary and interdisciplinary. We propose a picture that is unprecedented in its inclusiveness and breadth, which clearly shows that humans were initially apex predators, who specialized in hunting large animals. As Darwin discovered, the adaptation of species to obtaining and digesting their food is the main source of evolutionary changes, and thus the claim that humans were apex predators throughout most of their development may provide a broad basis for fundamental insights on the biological and cultural evolution of humans.”

Featured image: Human Brain © Dr. Miki Ben Dor

Reference: Ben‐Dor, M, Sirtoli, R, Barkai, R. The evolution of the human trophic level during the Pleistocene. Yearbook Phys Anthropol. 2021; 1– 30. https://doi.org/10.1002/ajpa.24247

Provided by Tel Aviv University

Journey Of a Skull: How A Single Human Cranium Wound Up Alone in A Cave in Italy (Paleontology)

Rare evidence from Eneolithic cranium suggests funerary treatment of corpse

A lone cranium in an Italian cave wound up there after being washed away from its original burial site, according to a study published March 3, 2021 in the open-access journal PLOS ONE by Maria Giovanna Belcastro of the University of Bologna, Italy and colleagues.

In 2015, archaeologists discovered a single human cranium (a skull without a lower jaw) in a gypsum cave in Northern Italy called Marcel Loubens cave. Caves are known to have been used for funerary practices in ancient Italy, but the fact that there are no other human remains in this cave has raised questions about how this skull came to be there, inspiring the researchers in this study to conduct a detailed analysis on the bone.

MLC in frontal (a), superior (b), left (c), posterior (d), inferior (e) and right (f) views. The boxes indicate the Zones (A-M) with the ectocranial lesions. © Belcastro et al, 2021, PLOS ONE (CC-BY 4.0, https://creativecommons.org/licenses/by/4.0/)

The structure of the bone indicates that it belonged to a woman between 24 and 35 years old at death. Carbon dating places the remains between 3630-3380 BC, during the Eneolithic period. Several lesions on the bone appear to be damage caused during the removal of soft tissues after death as part of a funeral ritual, while other damage and encrusted sediment on the bone are evidence that it was moved by natural processes not long afterward.

With this evidence, the researchers reconstructed the journey of the skull. After being treated and laid to rest in a burial place, the skull of this corpse rolled away, most likely moved by water and mud down the slope of a sinkhole and into the cave. Later, continued sinkhole activity created the modern structure of the cave, with this bone still preserved within. Besides revealing this fascinating story, this specimen also likely represents evidence of funerary treatment of a corpse in Italy during this time period.

The authors add: “An intriguing archaeological cold case: an isolated human cranium was found in the natural Marcel Loubens gypsum Cave (Bologna area, northern Italy) at the top of a vertical shaft, reached by an artificial 12-metre technical climb. How and when did it get there? Whose was it?

The cadaver (or head) of an early Eneolithic young woman was likely manipulated and dismembered in a funerary or ritual context and the skull, after a long and bumpy ride, accidentally ended up in the cave in the position in which it was found!”

Featured image: MLC on the top of the shaft and Lucia Castagna, the young archaeologist of GSB-USB that secured and recovered the cranium (Archive SABAP-BO/GSB-USB, ph. F. Grazioli) © Belcastro et al, 2021, PLOS ONE (CC-BY 4.0, https://creativecommons.org/licenses/by/4.0/)

Reference: Belcastro MG, Nicolosi T, Sorrentino R, Mariotti V, Pietrobelli A, Bettuzzi M, et al. (2021) Unveiling an odd fate after death: The isolated Eneolithic cranium discovered in the Marcel Loubens Cave (Bologna, Northern Italy). PLoS ONE 16(3): e0247306. https://doi.org/10.1371/journal.pone.0247306

Provided by PLOS

Help Is A Long Way Away: The Challenges of Sending Humans to Mars (Planetary Science)

On July 20, 1969, Apollo 11 astronaut Buzz Aldrin stepped out a lunar lander onto the surface of the moon. The landscape in front of him, which was made up of stark blacks and grays, resembled what he later called “magnificent desolation.”

When it comes to desolation, however, the moon may have nothing on Mars. 

The red planet circles the sun at an average distance of about 140 million miles from Earth. When people eventually visit this world—whether that’s in 20 years or 50—they may face a journey lasting 1,000 days or longer. The entire Apollo 11 mission, in contrast, lasted just a little over eight days. If future Mars astronauts get lonely, or if something more serious goes wrong, help is a long way away.

For researchers who study how human bodies and minds respond to the rigors of space travel, the scenario poses a lot of unknowns.

“We have never put someone in space for that long,” said Allie Anderson, an assistant professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences. “There will be a lot of challenges we can’t predict because the human body doesn’t always behave as we predict when living in space.”

Those challenges are in the spotlight again after NASA successfully landed its most recent non-human astronaut, a rover named Perseverance, on the surface of Mars Feb. 18. They’re also the bread and butter of researchers studying bioastronautics, or the study and support of life in space, at CU Boulder.

Anderson, for example, explores high-tech clothing that can monitor the health of astronauts as they live and work on Mars. Her research, she added, has evolved a lot as people across the globe are feeling increasingly isolated in their own lives. A second team led by engineer David Klaus studies how space habitats that employ “smart systems,” such as intelligent robots, might one day help humans to survive on the surface of an alien world.

It’s a research focus that comes with zero room for error, said Klaus, a professor of aerospace engineering sciences at CU Boulder. 

“Today, if something breaks on the International Space Station, astronauts can always get into a capsule and come home,” he said. “When you start getting out toward Mars, you’re very far away. You can’t rely on ground control.”

The stillness of space

Top: Allie Anderson (middle, in helmet) participates in a class held in southern Utah and led by the CU Anschutz Medical Campus simulating the challenges of providing medical care on Mars; bottom: A patch of fabric that weaves in electrodes for monitoring human heart signals. (Credits: NASA/JPL-Caltech/Anderson lab)

Anderson noted that space can be a dangerous environment but also one that brings a sense of tranquility. It’s something she got to experience herself, if only for a few seconds in 2015. The engineer, who was then a postdoctoral researcher studying how low gravity environments can affect human eyesight, had the opportunity to ride on one of NASA’s famous parabolic flights—large airplanes that fly high into the air then plummet quickly to make passengers feel like they’re weightless.

In a recent video, Anderson described a moment she had to herself at the end of that flight: “I gently push off, and in that 20 second window, I get to just float and experience the calmness and stillness of space.”

For the engineer, who refers to herself as a “little bit of a Martian” because of her passion for that planet, the feeling was short-lived. For Mars astronauts, that stillness will be an everyday reality. Even communicating with friends and family back home will be an ordeal. If you speak into a microphone on Mars, it can take anywhere from about five to 20 minutes for someone on Earth to hear your call. Mental health interventions like psychotherapy will be nearly impossible.

“Astronauts aren’t going to be able to take a vacation from that environment,” Anderson said.

So she and her colleagues, among other research projects, are trying to work within that uncertainty. They’re designing tools and strategies that may one day allow health professionals on Earth to monitor and even treat Mars explorers when they’re feeling stressed out.

Katya Arquilla, a graduate student working with Anderson, sees a lot of parallels to the challenges of providing mental health resources on Earth.

“A big issue is to get over the stigma of mental health,” she said. “That’s a problem we see here on Earth all the time—getting people to realize that they may have a mental illness and to seek help.”

In one project, Arquilla and Anderson have devised new ways of collecting electrocardiogram (ECG) data on human patients. These heart signals, which are often used to diagnose heart attacks and similar health problems, can give medical personnel a window into how people are handling stress. Normally, doctors rely on obtrusive and uncomfortable adhesive electrodes to take ECG data. Arquilla, in contrast, developed and tested new kinds of woven electrodes that can be incorporated into the fabric of a normal, tight-fitting T-shirt.

Arquilla said that her thinking about the project has changed during the COVID-19 pandemic. Today, millions of Americans—not just highly-trained astronauts—are undergoing the kind of loneliness and isolation that may await future Mars explorers. She hopes her research can make their lives better, too.

“I think the conversation on mental health here in the United States is finally shifting in a healthy direction,” she said. “Hopefully, these types of technologies can be integrated into care on Earth, as well.”

Habitats as ecosystems

When people from Earth finally make it to Mars, they’ll need someplace to sleep—and those future living spaces will have to be much more than just homes, said Patrick Pischulti, a graduate student working on Klaus’ team.

Top: Graduate students (from left) Patrick Pischulti, Annika Rollock and Ray Pitts in front of a full-sized model of a space shuttle nose cone on the CU Boulder campus
bottom: An artist’s depiction of what a space habitat might look like. (Credits: CU Boulder College of Engineering and Applied Science; NASA)

“For astronauts, the space habitat is their ecosystem,” he said. “It provides oxygen. It provides water. It protects them from the dangers of the space environment.”

Klaus, Pischulti and their colleagues are focusing on how NASA and other space agencies can keep these delicate ecosystems “alive” even when humans aren’t onboard. In other words, how can a space habitat continue to function when there are no astronauts around to perform routine maintenance? The research is part of a NASA-funded initiative called the Habitats Optimized for Missions of Exploration (HOME) Space Technology Research Institute, which is led by the University of California, Davis.

That’s important for Mars exploration in which habitats may sit empty for months in between crewed missions, Klaus said.  

“With the exception of a few short durations in between Skylab missions in the 1970s and during the early International Space Stations construction phase, there’s never been an opportunity or a need in NASA’s missions to have a human spacecraft with no humans onboard,” he said.

The key to developing these kinds of self-sufficient homes may lie in “smart systems.” That’s a catchall term for intelligent machines, from vacuuming robots to floating networks of fire detectors, that can work in tandem with human users. NASA, for example, has already sent three robots collectively known as Astrobee to the International Space Station. The space agency is testing whether these flying, cube-shaped machines will be able to help astronauts complete their daily chores, such as shuttling objects around the station.

On Earth, there are no shortage to these kinds of tools, said Annika Rollock, a graduate student working on the HOME project. She and her colleagues, however, are seeking to better understand which ones may be critical for keeping astronauts healthy and safe—and which ones might only get in the way or, even worse, put human lives at risk.

“We have to say, ‘This AC unit or fire detector works great in an apartment building, but it won’t work in space, or it’s not going to be worth sending it into space,” Rollock said.

For now, working in the field of bioastronautics can take a lot of patience—it may be decades, if not longer, before we see an Earthling set foot on Mars. But Anderson is hopeful, at least, that she’ll see her hard work make it to the red planet one day. 

“I am hoping to see somebody stand on the surface of Mars before I die,” she said. “Even though I think I’ll be an old woman when that happens.”

Provided by University of Colorado Boulder

Ancient Skeletal Hand Could Reveal Evolutionary Secrets (Paleontology)

A 4.4 million-year-old skeleton could show how early humans moved and began to walk upright, according to new research led by a Texas A&M anthropology professor.

Evolutionary expert Charles Darwin and others recognized a close evolutionary relationship between humans, chimps and gorillas based on their shared anatomies, raising some big questions: how are humans related to other primates, and exactly how did early humans move around? Research by a Texas A&M University professor may provide some answers.

Thomas Cody Prang, assistant professor of anthropology, and colleagues examined the skeletal remains of Ardipithecus ramidus (“Ardi”), dated to 4.4 million years old and found in Ethiopia. One of Ardi’s hands was exceptionally well-preserved.

The researchers compared the shape of Ardi’s hand to hundreds of other hand specimens representing recent humans, apes and monkeys (measured from bones in museum collections around the world) to make comparisons about the kind of locomotor behavior used by the earliest hominins (fossil human relatives).

The results provide clues about how early humans began to walk upright and make similar movements that all humans perform today.

This discovery is described in a study published in the current issue of Science Advances.

“Bone shape reflects adaptation to particular habits or lifestyles – for example the movement of primates – and by drawing connections between bone shape and behavior among living forms, we can make inferences about the behavior of extinct species, such as Ardi, that we can’t directly observe, Prang said.

“Additionally, we found evidence for a big evolutionary ‘jump’ between the kind of hand represented by Ardi and all later hominin hands, including that of Lucy’s species (a famous 3.2 million-year-old well-preserved skeleton found in the same area in the 1970s). This ‘evolutionary jump’ happens at a critical time when hominins are evolving adaptations to a more human-like form of upright walking, and the earliest evidence for hominin stone-tool manufacture and stone-tool use, such as cut-marks on animal fossils, are discovered.”

Prang said the fact that Ardi represents an earlier phase of human evolutionary history is important because it potentially shines light on the kind of ancestor from which humans and chimpanzees evolved.

“Our study supports a classic idea first proposed by Charles Darwin in 1871, when he had no fossils or understanding of genetics, that the use of the hands and upper limbs for manipulation appeared in early human relatives in connection with upright walking,” he said. “The evolution of human hands and feet probably happened in a correlated fashion.”

Since Ardi is such an ancient species, it might retain skeletal features that were present in the last common ancestor of humans and chimpanzees. If this is true, it could help researchers place the origin of the human lineage – in addition to upright walking – into a clearer light.

“It potentially brings us one step closer to an explanation for how and why humans evolved our form of upright walking,” Prang said.

He added that the big change in hand anatomy between Ardi and all later hominins occurs at a time, roughly between 4.4 and 3.3 million years ago, coinciding with the earliest evidence of the loss of a grasping big toe in human evolution. This also coincides with the earliest known stone tools and stone cut-marked animal fossils.

He said it appears to mark a major change in the lifestyle and behavior of human relatives within this timeframe.

“We propose that it involves the evolution of more advanced upright walking, which enabled human hands to be modified by the evolutionary process for enhanced manual manipulation, possibly involving stone tools,” Prang said

This research was funded by the Wenner Gren Foundation.

Featured image: The skeletal fragments of “Ardi.” © Wikimedia Commons

Reference: Thomas C. Prang, Kristen Ramirez, Mark Grabowski and Scott A. Williams, “Ardipithecus hand provides evidence that humans and chimpanzees evolved from an ancestor with suspensory adaptations”, Science Advances  24 Feb 2021: Vol. 7, no. 9, eabf2474 DOI: 10.1126/sciadv.abf2474

Provided by Texas A&M

The World’s Largest Animal Genome (Biology)

The Australian lungfish replaces the Mexican axolotl as holding the record for the “largest genome in the animal kingdom”. Its genome shows the evolutionary innovations that made living on land possible.

380 million years ago, the first fish began to conquer land. The Australian lungfish – an endangered air-breathing species – is one of the few living relatives of these first “land fish”.

An international research team has now used the latest DNA sequencing technologies to decode the huge genome of this fish species for the first time. The analysis has been published in the journal Nature. It gives new insights into the evolutionary innovations that enabled fish to live on land.

The study was a team effort of researchers from Hamburg, Constance, Vienna, Lyon and Würzburg. Senior Professor Manfred Schartl from the Biocentre of Julius-Maximilians-Universität (JMU) Würzburg in Bavaria, Germany, an expert in the biology and evolution of fish, was an important contributor to the study as was his postdoc Kang Du and Susanne Kneitz, a bioinformatician from the JMU Chair of Biochemistry and Cell Biology.

Genome is 14 times larger than that of humans

According to the study, the lungfish genome is the largest animal genome ever sequenced. Boasting 43 billion base pairs, it is 14 times larger than the human genome, exceeding the genome of the axolotl, the previous record holder in the animal kingdom, by an impressive 30 percent.

So why is the genome so large? Astonishingly, the lungfish does not have many more genes than other vertebrates. But it does have more mobile genetic elements, so-called transposable elements. “These elements can be consider as a kind of computer virus. They multiply on their own but don’t have a function. As a scientist you wonder why the ‘genetic hard drive’ of the lungfish has not crashed long ago given the high number of transposable elements,” says Manfred Schartl.

Fins similar to human limbs

The Australian lung fish (Neoceratodus forsteri) lives in slow flowing rivers and bodies of standing water. Due to its newt-like physique, it was incorrectly assumed to be part of the amphibians in the 19th century. Today we know that as a lungfish it belongs to an archaic group of aquatic creatures from which all terrestrial vertebrates developed.

The “fleshy” fins of the lungfish possess an anatomical bone arrangement which looks already similar to that of human limbs. This allows the Australian lungfish to move like salamanders in water and on land. Moreover, they have lungs which allow them to breathe air above water so as not to drown. And they are capable of detecting airborne smells.

Closer to amphibians than to fish

The genome analysis reveals striking similarities between the Australian lungfish and terrestrial vertebrates. For example, the number and the spatial and temporal expression patterns of genes that are associated with the development of lungs, jointed limbs and with the detection of airborne smells are much more similar to amphibians and other land vertebrates than their fish relatives.

So far, scientists have debated controversially whether lungfish or the equally archaic coelacanths are more closely related to terrestrial vertebrates The study in Nature now shows that the lungfish are genetically closer to land animals and humans: 420 million ago, they split off from the coelacanths and formed a lineage leading to land animals.


Since 2018, the German Research Foundation (DFG) has funded the sequencing of the lungfish genome by JMU Professor Manfred Schartl, Professor Torsten Burmester (University of Hamburg) and Professor Axel Meyer (University of Constance) with more than EUR 500,000.

Featured image: The bone arrangement in the fins of the Australian lungfish is very similar to that in humans limbs. (Image: Uni Konstanz / Pixabay)


Axel Meyer, Siegfried Schloissnig, Paolo Franchini, Kang Du, Joost Woltering, Iker Irisarri, Wai Yee Wong, Sergej Nowoshilow, Susanne Kneitz, Akane Kawaguchi, Andrej Fabrizius, Peiwen Xiong, Corentin Dechaud, Herman Spaink, Jean-Nicolas Volff, Oleg Simakov, Thorsten Burmester, Elly Tanaka, Manfred Schartl: “Giant Lungfish genome elucidates the conquest of land by vertebrates”. Nature, 18 January 2021. DOI: 10.1038/s41586-021-03198-8

Provided by University of Wruzburg

From Coelacanths to Humans−What Evolution Reveals about the Function of Bitter Receptors (Biology)

To evaluate the chemical composition of food from a physiological point of view, it is important to know the functions of the receptors that interact with food ingredients. These include receptors for bitter compounds, which first evolved during evolution in bony fishes such as the coelacanth. What 400 million years of evolutionary history reveal about the function of both fish and human bitter receptors was recently published in the journal Genome Biology and Evolution by a team of researchers led by the Leibniz Institute for Food Systems Biology at the Technical University of Munich and the University of Cologne.

Evolutionarily, bitter receptors are a relatively recent invention of nature compared to other chemoreceptors, such as olfactory receptors. Their function of protecting vertebrates from consuming potentially toxic substances has long been scientifically recognized. More recent are observations that bitter receptors have other functions beyond taste perception. These include roles in defense against pathogenic bacteria, in metabolic regulation, and possibly also functions as sensors for endogenous metabolites and hormones.

Coelacanth and zebrafish in comparison

The team of scientists led by biologists Sigrun Korsching of the University of Cologne and Maik Behrens of the Leibniz Institute for Food Systems Biology now provides further evidence to support this hypothesis. In their current study, the team compared two original bitter receptor types from the coelacanth (Latimeria chalumnae) with four others from the zebrafish (Danio rerio) phylogenetically, functionally and structurally. To this end, the research team conducted, among other experiments, extensive functional studies using an established cell-based test system as well as a computer-based modeling approach. The goal was to gain a deep insight into the evolutionary history of bitter receptors in order to learn more about their functions.

As the study results show, both fish species possess, amongst others, a pair of homologous bitter receptor genes that presumably arose from a primordial gene. In this regard, the bitter recognition spectra of these fish receptors were largely identical despite 400 million years of separate evolution, according to the results of the functional studies. “What is particularly exciting about our results is that the original fish receptors recognized substances in the cellular test system which are still detected by human bitter receptors to date. These include bile acids,” says co-author Antonella Di Pizio of the Leibniz Institute.

Over 400 million years of selection pressure

“So there  must have been selective pressure at least until humans evolved, that means human bitter receptors can still detect the same bitter substances as a bony fish did over 400 million years ago,” concludes taste researcher Maik Behrens. Sigrun Korsching adds, “This speaks for one or more important functions of bitter receptors, even during human evolution.”

“Coelacanths are carnivores. Therefore, one could speculate that the existence of a bitter receptor variant that mainly recognizes steroid hormones and bile acids protects against the consumption of poisonous fish, which can contain not only bile acids but also highly potent neurotoxins in their liver and gallbladder. For example, the poisonous puffer fish Arothron hispidus lives in the same waters as the coelacanth,” says Maik Behrens. “In humans and also in zebrafish, however, it is questionable whether such a receptor variant would have been preserved from an evolutionary point of view if it did not have other functions inside the body. Another argument in favor of such extraoral functions is that bitter receptors are also found on human organs such as the heart, brain or thyroid gland,” Behrens added. One goal of his research is to help understand the effects of bitter substances on a systems biological level, regardless of whether they entered the body through food or whether they belong to the body’s own substances.

Featured image: Latimeria chalumnae, a species of coelacanth (family Latimeriidae). Graphic by Sabine Bijewitz, Template: Drawing by former FishBase artist Robbie Cada.


Behrens M, Di Pizio A, Redel U, Meyerhof W, Korsching SI (2020) Genome Biol Evol, evaa264, DOI: 10.1093/gbe/evaa264. At the root of T2R gene evolution: Recognition profiles of coelacanth and zebrafish bitter receptors

Provided by Leibneiz Institute for food Systems Biology at TUM