Tag Archives: ancestor

Kissing Likely Evolved in Our Common Ancestor with Great Apes 21 Million Years Ago

Posted on by
Reply

Kissing is common among most living great apes and likely was practiced by Neanderthals, having evolved in the ancestors of these groups between 21.5 million and 16.9 million years ago, according to a study led by researchers from Oxford University.

Neanderthal. Image credit: Gemini AI.

Kissing can be observed in various animal species, yet it poses an evolutionary enigma. While it carries significant risks, such as disease transmission, it lacks clear reproductive or survival advantages.

Until now, the evolutionary background of kissing has received limited attention, despite its cultural and emotional importance across numerous human societies.

In this recent study, Dr. Matilda Brindle and her team from the University of Oxford undertook the first investigation into the evolutionary history of kissing, utilizing a cross-species perspective based on primate family trees.

The findings indicated that kissing is an ancient characteristic of great apes, having developed in their ancestors between 21.5 and 16.9 million years ago.

This behavior has persisted through evolution and is still evident in most great apes.

The researchers also concluded that Neanderthals, distant relatives of modern humans, likely engaged in kissing as well.

This evidence, alongside earlier studies showing that humans and Neanderthals exchanged oral microbes (through saliva) and genetic material (via interbreeding), strongly implies that kissing occurred between the two species.

Dr. Brindle stated: “This marks the first exploration of kissing from an evolutionary standpoint.”

“Our results contribute to an expanding body of research that illuminates the incredible variety of sexual behaviors found among our primate relatives.”

To carry out the analysis, scientists needed to define what constitutes a kiss.

This task was challenging due to the numerous mouth-to-mouth interactions resembling kisses.

Given their investigation spanned a diversity of species, the definition had to be suitable for a wide range of animals.

Consequently, they defined kissing as non-aggressive mouth-to-mouth contact that does not involve food transfer.

After establishing this definition, the researchers concentrated on groups of monkeys and apes that evolved in Africa, Europe, and Asia, gathering data from the literature where kissing has been documented in modern primates.

Among these are chimpanzees, bonobos, and orangutans, all of which have displayed kissing behavior.

Following that, they conducted a phylogenetic analysis, treating kissing as a “trait” to map onto the primate family tree.

Using a statistical method known as Bayesian modeling, they simulated various evolutionary scenarios along the tree’s branches and calculated the chances that different ancestors also kissed.

The model ran 10 million simulations, producing robust statistical estimates.

Professor Stuart West from the University of Oxford noted: “Integrating evolutionary biology with behavioral data enables us to draw informed conclusions about non-fossilized traits like kissing.”

“This paves the way for studying the social behaviors of both extant and extinct species.”

While the researchers caution that current data is limited, particularly beyond great apes, this study sets a framework for future inquiries and offers primatologists a consistent method for documenting kissing behaviors in non-human animals.

“Though kissing may seem like a universal act, it’s only documented in 46% of human cultures,” remarked Dr. Katherine Talbot from the Florida Institute of Technology.

“Social customs and situations differ vastly among societies, prompting the question of whether kissing is an evolved behavior or a cultural construct.”

“This research represents a first step in addressing that question.”

This is part of a study published this week in the journal Evolution and Human Behavior.

_____

Matilda Brindle et al. 2025. A comparative approach to the evolution of kissing. Evolution and Human Behavior in press. doi: 10.1016/j.evolhumbehav.2025.106788

Source: www.sci.news

The Reconstructed Skull Reveals Fascinating Insights into Our Mysterious Ancestor

Posted on by
Reply

The Yunxian 2 skull, although deformed, has been reconstructed to resemble an early Denisovan.

Gary Todd (CC0)

Our species’ origins may extend further back than previously believed, and the same could hold true for both our extinct Neanderthal and Denisovan relatives. A recent analysis of fossil remains suggests that the common ancestors of these groups emerged over a million years ago.

“If these ancient divergences are accurate, we might be overlooking significant details about the early history of these lineages,” states Chris Stringer from the Natural History Museum in London.

This finding could clarify the search for “ancestor X,” the lineage from which modern humans, Neanderthals, and the population that produced the Denisovans descended. It also may imply that the Denisovans were our closest relatives, potentially even closer than Neanderthals—a point that remains debated.

Stringer and his research team, which includes Xijun Ni from the Institute for Vertebrate Paleontology and Paleoanthropology in Beijing, revisited the Yunxian fossil collection located in central China.

Two partial skulls were unearthed on a terrace above the Han River in 1989 and 1990; reported in 1992. Both skulls were crushed during their discovery, although the YUNXIAN 2 specimen sustained less damage.

Using advanced techniques, Stringer, Ni, and their colleagues reconstructed the Yunxian 2 skull. These methods include CT scans that digitally separate individual bone fragments from the surrounding sediment. “The skull is elongated and has a prominent brow ridge,” Stringer notes. “Additionally, it features a slight beak-like nose, small third molars, and larger teeth.”

The Yunxian 2 skull dates back between 940,000 and 1.1 million years. Specimens of this age are often classified as Homo erectus, which appeared around 2 million years ago in Africa before dispersing to South Asia and Indonesia approximately 108,000 years ago. However, Stringer asserts that Yunxian 2 doesn’t conform to this profile; many of its features are characteristic of later specimens, including Neanderthals.

To better understand the Yunxian 2, the research team compared it with 56 other fossils of the same group. They constructed a family tree based on the morphology, grouping related fossils together. This analysis revealed three significant lineages, encompassing most fossils from the past million years.

One lineage consists of modern humans (Homo sapiens), another includes Neanderthals (Homo neanderthalensis) who lived in Europe and Asia for several hundred thousand years before disappearing around 40,000 years ago, and the third represents the Denisovans from East Asia.

Denisovans were first identified in 2010 through DNA from a bone fragment, and it took 15 years to connect this lineage with larger fossils. Stringer was involved in interpreting the Harbin skull from China, which was identified as Denisovan in June based on molecular evidence. Yunxian 2 appears to fall into the early Denisovan category, much like several other Asian fossils.

This discovery provides important links among these fossils in the Denisovan lineage, according to geneticist Aylwyn Scally at Cambridge University: “This allows us to form better hypotheses about the Denisovans’ whereabouts, lifestyle, and species characteristics.”

Recognizing that Yunxian 2 is a Denisovan reshapes our recent understanding of human evolution in two significant ways. First, it appears to alter the timeline of the emergence of these three groups. Traditional genetic narratives suggest that the common ancestor, “ancestor X,” diverged into two branches. However, the reconstruction indicates that Neanderthals separated first about 1.38 million years ago, before the divergence of modern humans and Denisovans around 1.32 million years ago.

If validated, this hypothesis posits that Denisovans were indeed more closely related to us than Neanderthals, challenging established genetic theories. Nonetheless, Scally expresses caution, noting the complexities of inter-group histories: “In reality, straightforward phylogenetic trees don’t provide a complete picture.” The research relies more on “entangled networks” than traditional models. Furthermore, Scally suggests that genetics may provide clearer insights into these relationships than morphology, especially with only partial skeletal evidence available.

The second significant change is that all three groups appear to have emerged much earlier than previously thought. Genetic evidence generally indicates that modern humans split from their Neanderthal and Denisovan relatives around 500,000-700,000 years ago. However, Yunxian 2 suggests that the Denisovan lineage was already distinct one million years ago.

Scally adds that there may not be a single definitive date for these splits; instead, they likely occurred over extended periods with intermittent separations and reunions. In this case, Stringer and his colleagues may be correct that divergence began over a million years ago, stretching across hundreds of thousands of years.

This extended timeline raises new questions. The oldest known fossils of modern humans date to around 300,000 years ago. So where are the earlier ancestors from millions of years ago? “We either lack those fossils, or they’re present but unrecognized,” Stringer comments.

We also know little about “ancestor X”—its appearance and habitat remain a mystery. “Ten years ago, I would have stated that the likely origin of most of these groups was Africa,” Stringer reflects. “It now seems plausible that their forebears lived outside Africa, potentially in regions of Western Asia. This suggests that ancient sapiens ancestors likely migrated to Africa, evolving there for a large portion of that million-year timeline.”

Stringer highlights the scarcity of known fossils from Western Asia dating back a million years, noting that even India has limited evidence. Only one human fossil from that period exists. “There are numerous regions where our fossil record is strikingly thin,” he asserts.

A significant source of information is the Yunxian site. In 2022, a third skull was uncovered that seems to be in better condition, although it has yet to be analyzed.

Neanderthals, Ancient Humans, Cave Art: France

Join New Scientist’s Kate Douglas on an enthralling journey through time as she delves into significant Neanderthal and Upper Paleolithic sites across southern France, from Bordeaux to Montpellier.

Topic:

Source: www.newscientist.com

New Fossil Reveals Cambrian Nectocalid as an Early Ancestor of the Arrow Bug

Posted on by
Reply

Nectakarizids are enigmatic Paleozoic creatures with a debatable classification. These beings evolved for aquatic life, boasting fins, camera-like eyes on stalks, and paired tentacles. Earlier theories proposed they belonged to a unique crustacean-like phylum, notochord, cephalopods, or even radioyoloons. However, new fossil discoveries from North Greenland indicate that Nectocalids are actually the early relatives of Arrow worms, also known as Chaetognaths. This discovery suggests that these relatively simplistic marine arrow worms had ancestors that played a significant predatory role within much more intricate anatomical structures and food webs.

Reconstructing the life of Nektognathus evasmithae. Image credit: Bob Nichols.

“About 15 years ago, a study based on the notable Burgess Shale fossil suggested that Nectochalidosis is a type of cephalopod,” said Jacob Vincer, a paleontologist at the University of Bristol.

“This argument seemed illogical to me as it contradicts much of what I understand about the taxonomy of these organisms.

In the recent research, Dr. Vinther and his team described Nektognathus evasmithae, a newly identified Nectocalid from the Sirius Passett Lagerstätte, dating back 519 million years in North Greenland.

By examining 25 fossil specimens of Nektognathus evasmithae, they successfully positioned the Nectocalid within the Tree of Life.

“We found that remnants of the nervous system manifested as paired mineralized structures, providing insight into these animals’ position in the evolutionary tree,” Dr. Winter remarked.

Nektognathus evasmithae holotype. Image credit: Vinther et al., doi: 10.1126/sciadv.adu6990.

Recently, paleontologists found a fossil from Sirius Passett, which belongs to a different branch of the evolutionary tree—a small group of swimming organisms known as arrow bugs and Chaetognaths.

“These fossils exhibit distinctive traits that set them apart from arrow worms, particularly the abdominal ganglia,” explains Dr. Tae Yoon Park, a paleontologist at the Korean Institute of Polar Research.

The abdominal ganglia consist of large nerve clusters situated above the abdomen in living arrow bugs, typical for this type of creature.

The distinctive anatomical features, coupled with unique preservation conditions, indicate that they may be replaced by phosphate minerals during the decomposition process.

“We now have a compelling piece of evidence to resolve the Nectkalido debate,” Dr. Park stated.

“Nectocaridids share numerous features with other fossils that are also part of the arrow worm lineage.”

“Many of these characteristics may superficially resemble squid and demonstrate a simple adaptation of invertebrates to a more dynamic swimming lifestyle, paralleling how whales and ancient marine reptiles evolved similar traits for their aquatic lifestyles.”

“Nectakalids possess complex camera-like eyes akin to ours,” Dr. Vincer elaborated.

“Contemporary arrow worms have a limited ability to form images, primarily detecting movement in well-lit environments.”

“Thus, the ancestors of arrow worms were indeed sophisticated predators, much like squids that appeared around 400 million years later.”

“Consequently, we can illustrate how arrow worms have a more significant role in the food chain than previously thought.”

“Our fossils are notably larger than the average living arrow worm and likely feature various adaptations for swimming, such as eyes and elongated antennae.

“To further substantiate the carnivorous nature of Nectkalizids, we discovered several specimens containing the remains of a swimming arthropod known as Isoxys in their gastrointestinal tract.

This study was published this week in the journal Advances in Science.

____

Jacob Winter et al. 2025. Fossilized abdominal ganglia reveal the affinity of Chaetognaths for Cambrian calizids. Advances in science 11 (30); doi:10.1126/sciadv.adu6990

Source: www.sci.news

New research suggests that modern humans are descended from two ancestor groups

Posted on by
Reply

Over the past 20 years, a general view of human evolutionary genetics is Homo sapiens It first appeared in Africa about 200,000 to 300,000 years ago, and descended from a single lineage. However, a new study from the University of Cambridge shows that modern humans are the result of two groups (potentially HOMO HEIDELBERGENSIS and Homo Erectus) It branched out 1.5 million years ago and gathered at a mixed event 300,000 years ago at an 80:20% ratio.

a HOMO HEIDELBERGENSISNeanderthals and Cromagnone. Image credit: Sinc/José Antonio Peñas.

“The question of where we came from has been something that has captivated people for centuries,” said Dr. Trevor Cousins ​​of Cambridge University.

“For a long time, it has been assumed that we evolved from a single, consecutive ancestor lineage, but the exact details of our origins are uncertain.”

“Our research shows clear indications of the origins of our evolutionary being more complex, including various groups that have developed individually over a million years, and have since returned to form modern human species,” added Richard Durbin, a professor at Cambridge University.

Previous studies have already shown that Neanderthals and Denisovans are mated, but Homo sapiens About 50,000 years ago, new research suggests that a much more important genetic mixing occurred long before these interactions were about 300,000 years ago.

Unlike Neanderthal DNA, which makes up about 2% of the genome of non-African modern humans, this ancient mixed event contributes ten times its amount and is found in all modern humans.

The team's methods rely on analysis of modern human DNA rather than extracting genetic material from ancient bones, allowing us to infer the existence of ancestral populations that otherwise left no physical traces.

The authors developed a computational algorithm called Cobraa, which models the methods that ancient populations fell apart and later integrated.

They tested the algorithm using simulated data and applied it to real human genetic data from the 1000 Genomes project, a global initiative that sequences DNA from populations in Africa, Asia, Europe and America.

Researchers were able to identify these two ancestral populations, but also identified some impressive changes that occurred after the two populations were initially decomposed.

“At the moment the two ancestral populations split, we see a serious bottleneck in one of them, suggesting that it had been reduced to a very small size before slowly growing over a million years,” said Professor Aylwyn of Cambridge University.

“This group later contributed to about 80% of modern human genetic material and also appeared to be a population of ancestors that diverged the Neanderthals and Denisovans.”

“However, some of the population genes that contributed to our small numbers of genetic material, especially those associated with brain function and neural processing, may play an important role in human evolution,” Dr. Cousins ​​said.

This is a reconstruction of the artist Homo Erectus. Image credit: Yale University.

Scientists also found that genes inherited from the second population are often separated from the genome regions associated with gene function, suggesting that they may be less compatible with numerous genetic backgrounds.

This suggests a process known as the cleansing of selection, in which natural selection removes harmful mutations over time.

So who was our mystical human ancestors? Fossil evidence suggests species such as Homo Erectus and HOMO HEIDELBERGENSIS Although he lived in both Africa and other regions during this period, becoming a potential candidate for these ancestral populations, more research (probably more evidence) is needed to identify which genetic ancestors correspond to which fossil groups.

The authors hope to refine the model to explain more progressive genetic exchanges between populations rather than sharp divisions or reunions.

They also plan to explore how their findings relate to other anthropology discoveries, such as fossil evidence from Africa, suggesting that early humans may have been much more diverse than previously thought.

“It's amazing to see today's DNA and reconstruct events that were hundreds of thousands or millions of years ago,” Professor Scally said.

“And we can tell you that our history is much richer and more complicated than we imagined.”

study It was published in the journal today Natural Genetics.

____

T. Cousins et al. The structured coalescence model reveals the deep ancestral structure shared by all modern humans. Nat GenetPublished online on March 18th, 2025. doi:10.1038/s41588-025-02117-1

Source: www.sci.news

New understanding suggests LUCA, the last common ancestor of all life, emerged earlier than previously believed

Posted on by
Reply

Illustration showing LUCA possibly being attacked by a virus

Scientific Graphic Design

The organisms that gave rise to all life on Earth evolved much earlier than previously thought – just a few hundred million years after Earth formed – and may have been more sophisticated than previous assessments had suggested.

The DNA of all living organisms today is E. coli There are many similarities in the evolution leading up to the blue whale, suggesting that we can trace our origins back to a universal common ancestor, LUCA, billions of years ago. While many efforts have been made to understand LUCA, studies taking a broader approach have revealed surprising results.

“What we're trying to do is bring together representatives from different disciplines to develop a comprehensive understanding of when LUCA existed and what its biological characteristics were,” he said. Philip Donahue At the University of Bristol, UK.

Genes that are currently present in all major lineages of life may have been passed down uninterrupted from LUCA, which could help us understand what genes our ancient ancestors had. By studying how these genes changed over time, we should be able to estimate when LUCA lived.

In reality, this is a lot more complicated than it sounds, as genes are lost, gained, and swapped between branches. Donohue says the team created a complex model that took this into account, to work out which genes were present in LUCA. “We've found a much more sophisticated organism than many have previously claimed,” he says.

The researchers estimate that 2,600 protein-coding genes come from LUCA, up from previous estimates of as few as 80. The team also concludes that LUCA lived around 4.2 billion years ago, much older than other estimates and surprisingly close to the formation of Earth 4.5 billion years ago. “This suggests that the evolution of life may have been simpler than previously claimed, because evolution happened so quickly,” Donohue says.

The earlier date is largely due to the team's improved methodology, but also because, unlike others, they don't assume that LUCA could have existed only after the Late Heavy Bombardment, when Earth was hit so hard by space debris that any new life that emerged could have been wiped out. Based on rocks returned from the Moon, the period has been put at 3.8 billion years ago, but there's a lot of uncertainty around that number, Donohue says.

Their reconstruction suggests that LUCA had genes that protected it from ultraviolet damage, which leads them to believe that it likely lived on the ocean's surface. Other genes suggest that LUCA fed on hydrogen, which is consistent with previous findings. The team speculates that LUCA may have been part of an ecosystem with other types of primitive cells that are now extinct. “I think it's extremely naive to think that LUCA existed on its own,” Donohue says.

“I think this is compelling from an evolutionary perspective.” Greg Fournier “LUCA is not the beginning of the story of life, but merely the state of the last common ancestor that we can trace back to using genomic data,” say researchers from the Massachusetts Institute of Technology.

The results also suggest that LUCA had a primitive version of the bacterial defense system known as CRISPR to fight viruses. “Even 4.2 billion years ago, our earliest ancestors were fighting viruses,” the team members say. Edmund Moodyalso at the University of Bristol.

Peering into the distant past is fraught with uncertainty, and Donohue is the first to admit that his team may have missed the mark. “We've almost certainly got it all wrong,” he says. “What we're trying to do is push the envelope and create the first attempt to synthesize all of the relevant evidence.”

“This won't be the last word,” he said, “and it won't be our last word on this subject, but we think it's a good start.”

Patrick Forter Researchers at the Institut Pasteur in Paris, France, who coined the term LUCA, also believe that the organism did not live in isolation. “But the claim that LUCA lived before the Late Heavy Bombardment 3.9 billion years ago seems to me completely unrealistic,” says Forterre. “I'm convinced that their strategy for determining the age and gene content of LUCA has several flaws.”

topic:

Source: www.newscientist.com

Study reveals last common ancestor lived 4.2 billion years ago

Posted on by
Reply

The Last Universal Common Ancestor (LUCA) is a hypothetical common ancestor of all modern cellular life, from single-celled organisms such as bacteria to giant sequoia trees and even to us humans. Our understanding of LUCA therefore has implications for our understanding of the early evolution of life on Earth.

Probabilistic inference of metabolic networks for modern organisms present in LUCA. Image courtesy of Moody others., doi: 10.1038/s41559-024-02461-1.

LUCA is a node on the tree of life from which the basic prokaryotic domains (Archaea and Bacteria) branch off.

Modern life evolved from LUCA from a variety of different sources: the same amino acids used to build proteins in all cellular organisms, a shared energy currency (ATP), the presence of cellular machinery such as ribosomes involved in creating proteins from information stored in DNA, and even the fact that all cellular organisms use DNA itself as a way to store information.

In the new study, University of Bristol scientist Edmund Moody and his colleagues compared all the genes in the genomes of modern species and counted the mutations that had occurred in the sequences over time since a common ancestor called LUCA.

The time when some species split off is known from the fossil record, and the team used a genetic equivalent of a familiar equation used in physics to calculate speed to determine when LUCA existed, arriving at 4.2 billion years ago – just 400 million years after Earth and the solar system formed.

“The evolutionary history of genes is complicated by the exchange of genes between lineages,” Dr Moody said.

“Reconciling the evolutionary history of genes with species lineages requires the use of complex evolutionary models.”

“We didn't expect LUCA to be so old, within just a few hundred million years of Earth's formation,” said Dr Sandra Alvarez-Carretero, also from the University of Bristol.

“But our findings are consistent with modern views of the habitability of early Earth.”

The study authors also traced the lineage of life back to LUCA and modeled the physiological traits of modern species to elucidate LUCA's biology.

“One of the real advantages here is that we applied the gene tree and species tree reconciliation approach to a highly diverse dataset representing the major domains of life: Archaea and Bacteria,” said Dr Tom Williams from the University of Bristol.

“This allows us to make statements with some confidence about how LUCA lived and to assess that level of confidence.”

“Our study shows that LUCA was a complex organism not too different from modern prokaryotes, but what's really interesting is that LUCA clearly had an early immune system, indicating that by 4.2 billion years ago our ancestors were in an arms race with viruses,” said Professor Davide Pisani, from the University of Bristol.

“LUCA clearly used and transformed its environment, but it is unlikely to have lived alone,” said researcher Dr Tim Lenton, from the University of Exeter.

“That waste would then serve as food for other microorganisms, such as methanogens, helping to create a recycling ecosystem.”

“The insights and methods provided by this study will also inform future studies looking in more detail at the subsequent evolution of prokaryotes in the context of Earth's history, including the less-studied archaea and their methanogens,” said Professor Anja Spang, researcher at the Royal Netherlands Institute for Marine Research.

“Our study brings together data and methods from multiple disciplines, revealing insights into the early Earth and life that could not be achieved by any single discipline alone,” said Professor Philip Donoghue, from the University of Bristol.

“It also shows how quickly ecosystems were established on the early Earth.”

“This suggests that life may thrive in an Earth-like biosphere somewhere in the universe.”

This study paper Published in the journal today Natural Ecology and Evolution.

_____

ERR Moody othersThe nature of the last universal common ancestor and its impact on the early Earth system. Nat Ecol EvolPublished online July 12, 2024, doi: 10.1038/s41559-024-02461-1

This article is a version of a press release provided by the University of Bristol.

Source: www.sci.news