Wasous

Populations of indigenous people in southern Africa carry a gene that causes lighter skin, and scientists have now identified the rapid evolution of this gene in recent human history.

San man of Namibia [Credit: Ian Beatty/WikiCommons]

The gene that causes lighter skin pigmentation, SLC24A5, was introduced from eastern African to southern African populations just 2,000 years ago. Strong positive selection caused this gene to rise in frequency among some KhoeSan populations.

UC Davis anthropologist Brenna Henn and colleagues have shown that a gene for lighter skin spread rapidly among people in southern Africa in the last 2,000 years.

This is a "rare example of intense, ongoing adaptation in recent human history and is the first known example of adaptive gene flow at a pigmentation locus in humans," according to the paper published online in the Proceedings of the National Academy of Sciences.

The findings are based on research by multiple scientists. The primary author, Meng Lin, conducted the research as a graduate student at Stony Brook University, working with anthropologist Brenna Henn, now of the University of California, Davis, Genome Center and Department of Anthropology. Lin is now a post-doctoral researcher in genetics at the University of Southern California.

In previous work, the researchers looked at pigmentation variation in two KhoeSan populations from South Africa by performing a genome-wide association analysis in about 450 individuals. They followed up on the top associated gene, SLC24A5, by simulating population histories with and without positive selection. The DNA and pigmentation sampling took place in the Northern Cape of South Africa in the southern Kalahari Desert and Richtersveld regions.

Gene plays a role in lighter skin pigmentation

Individuals who carry two copies of the lighter pigmentation gene are 14 percent lighter-skinned than the population average, the researchers said. The gene SLC24A5 plays a key role in the genetic basis of light skin pigmentation.

While light skin is often associated with European ancestry, even in South Africa, the present-day Khoekhoe and San did not experience enough recent migration to account for the frequency of the gene. Rather, strong positive selection during the past 2,000 years was the only way to explain the current distribution. The gene, which is also present in people from the Near East and eastern Africa, was probably initially brought into the region by only a small number of individuals.

The actual source of the positive selection is not clear. The researchers theorize that a shift from consuming vitamin D-rich marine animals to consuming pasture animals, or a reduction in exposure to ultraviolent rays, might have changed skin pigmentation over time.

"While the biological cause of the selective event merits further investigation, we have demonstrated an unusual rapid case of selection for lighter skin pigmentation based on a recently introduced allele less that 2,000 years ago, the first case of pigmentation adaptation from migration in humans," the paper concludes.

Author: Karen Nikos-Rose | Source: UC Davis [December 10, 2018]

The analysis of the world’s most complete skeleton of an early human ancestor, conducted by a research collaboration involving the University of Liverpool, offers conclusive evidence that human ancestors became efficient upright walkers while they were still substantially tree dwelling animals.

Professor Ronald Clarke with Little Foot [Credit: University of Liverpool]

The first bones of the 3.67 million old skeleton, specimen StW 573 nicknamed ‘Little Foot’, were 12 foot bones and leg bone fragments identified in boxes in the 1990s. The rest of the skeleton has undergone two decades of painstaking excavation, cleaning, restoring and analysis. It was found in a very deep cavern, with the bone embedded in a concrete-like matrix. The bone is very delicate and in some cases literally paper-thin. However, it has given scientists a far greater understanding of how our species evolved.

Limbs intact

The over 90% complete skeleton of an old female, much more than twice as complete as the famous Lucy, and considerably older as well, Little Foot is a member of the genus Australopithecus, a widespread and varied genus of hominins to which Lucy belonged, and which was an early precursor to modern-day Homo sapiens which appeared roughly 300,000 years ago. Little Foot is the first fossil of Australopithecus ever to have been discovered with its limbs intact.

Little Foot’s fossil bones [Credit: Patrick Landmann/Science Photo Library]

The studies support the argument of her discoverer, Professor Ronald Clarke of the University of the Witwatersrand, that there were two species of Australopithecus living at the same time in South Africa’s ‘Cradle of Humankind’, Australopithecus africanus, which was small, like Lucy, and probably primarily tree-dwelling, and Australopithecus prometheus, which was probably just within the range of modern human stature.

Important finding

As part of the study, which has been reported in Nature Science, Professor Robin Crompton, Honorary University of Liverpool Research Associate in Musculoskeletal Biology, and his colleagues analysed how she would have walked.


Professor Crompton, states: “This hominin, for the first time in the fossil record, had longer lower limbs than upper limbs, like ourselves. This is an important finding, as the slightly older hominin Ardipithecus, which came before Australopithecus, had longer arms than legs – more like other great apes such as the gorilla.

“That means she was being selected for long stride length in bipedalism. Moreover, unlike Lucy, ‘Littlefoot’ had a hip joint like our own, able to transmit large forces from the trunk to the leg and vice versa. Although Little Foot’s legs were longer than her arms, they had not yet achieved the great relative leg length found in humans. Thus, she would not have been as good at carrying objects as we are. However, she would have been much better at climbing trees than modern humans.

“It is most likely that she would have resided in an area that was a mix of tropical rainforest, broken woodland and grassland, through which she would roam around. She would have lived primarily on forest fruits and leaves”

Source: University of Liverpool [December 10, 2018]

Otago researchers have discovered a rare case of genetic population discontinuity on the Mediterranean Island of Ibiza. Essentially, the original genetic signature of the founding female population, handed down through centuries on Ibiza has been replaced, prompting a change in understanding of the island’s genetic history.

Set of figurines from Es Culleram. Archaeological Museum of Ibiza and Formentera [Credit: © Ministerio de Cultura]

Ancient DNA from Ibiza demonstrates a clear genetic discontinuity in the maternal lineages of the early Phoenician settlers and the modern inhabitants of the island according to a study published in Scientific Reports.

The study was led by Professor Lisa Matisoo-Smith and her team from the University of Otago, New Zealand, and Professor Pierre Zalloua of the Lebanese American University, Beirut, with the collaboration of researchers from the Institute of Evolutionary Biology (Universitat Pompeu Fabra-CSIC), Barcelona, the Archaeological Museum of Ibiza and archaeologists from Lebanon and Italy.

The team analysed mitochondrial DNA (mtDNA), which is maternally inherited, from archaeological Phoenician remains and from modern inhabitants of Ibiza. They also obtained whole genome data (representing their total ancestry from both parents) from one ancient Phoenician individual.

Arriving from Cadiz, on the Iberian mainland, the Phoenicians first settled on the strategic island of Ibiza around 654 BCE and remained the main inhabitants of Ibiza for about seven centuries.

Burial rituals and other archaeological findings at the Puig des Molins necropolis of Ibiza provide evidence for a second population influx from Carthage or other Punic settlements in the Mediterranean, coinciding with a period of prosperity and major development of the island around 5th BCE. After the 2nd Punic War, Ibiza started a long process of integration of Ibiza into the Roman Empire, followed by the Islamic conquest of the island around 900 CE. Beginning around 1200 CE Ibiza was the recipient of migrations from the Iberian and Southern European mainland.

Based on the mtDNA results, the study showed clear genetic discontinuity between the early Phoenician settlers and the modern inhabitants of the island.

“Thus, the unusual genetic signature that has previously been identified in modern Ibizans does not appear to be the result of their Phoenician ancestry, at least from a maternal perspective”, explains Professor Matisoo-Smith.

Multiple population arrivals through invasions or other movements combined with periods of population instability after the early Phoenician settlement seems to have led to a reshuffling of the genetic makeup of this island.

“It is fascinating to see that the ancient maternal lineages were replaced over time. Today the mitochondrial DNA lineages in indigenous Ibizans appear to be most closely related to those of modern French, which may indicate a Catalonian connection,” adds Professor Zalloua.

While ancient DNA evidence generated over the last few years does now show us that there were population replacements in deep time, for example in Europe when farmers moved into western Europe several thousands of years ago and replaced many hunter-gatherer populations, we do not often see genetic replacement during more recent times.

Despite the lack of continuity observed in the mitochondrial genomes, previous Y chromosome analyses suggest that there is still some Phoenician signature in the modern Ibizan population. The whole genome data obtained from one ancient Phoenician from Ibiza belonged to an individual with a European maternal lineage but with a significant Eastern Mediterranean component to their genetic ancestry, indicating an admixed Phoenician community in Ibiza during the 3rd century BCE. This result is consistent with the archaeological evidence and further indicates that diversity and integration was a hallmark of Phoenician societies.

The results are consistent with historical evidence suggesting that Phoenician influence in the West was male dominated and indicates that there was not a total replacement of the Ibizan founding population, however, we now know that the genetic distinctness of the modern indigenous inhabitants of Ibiza is not due to Phoenician ancestry as has often been suggested. Further whole genome data is needed to help us understand why and how the genetic makeup of the Ibizan population changed over time. For example, disease or social impacts like war or famine may have played a major role in shaping the genetic makeup of the population of the island.

Source: University of Otago [December 07, 2018]

Is it in our nature to go to war? Should we just accept the fact that humans have this innate tendency and are hardwired to kill members of other groups?

Rock paintings in Tadrart Acacus region of Libya dated from 12,000 BC to 100 AD [Credit: WikiCommons]

No, says R. Brian Ferguson, professor of anthropology at Rutgers University-Newark. There is no scientific proof that we have an inherent propensity to take up arms and collectively kill.

In a study published in Scientific American, Ferguson argues that war may not be in our nature at all. People might fight and sometimes kill for personal reasons, but homicide, he argues, is not war.

"There is definitely controversy in the field when it comes to this question," says Ferguson, who studies human nature, war and peace. "But it is the overall circumstances that we live in that creates the impulse to go or not go to war."

In his study, "War May Not Be in Our Nature After All. Why We Fight", Ferguson reached back thousands of years to look at the historical roots of warfare to shed light on whether humans have always made war or if armed conflict has only emerged as changing social conditions provided the motivation and organization to collectively kill.

It's a topic he's been studying since the Vietnam War, a period in history that sparked his interest. His research is an attempt to settle an age-old academic debate over whether humans are hardwired to fight wars or if war is a human invention. If war is not ingrained in human nature, that may help provide a basis for arguing against war as an option, he says.

Many scientists and scholars believe that humans as a species are aggressive, brutal and bloodthirsty and this behavior is part of our DNA. Ferguson argues, however, that there is no real indication or scientific proof that humans have been waging war for the entire history of the species.

"Warlike cultures in some places became common only over the past 10,000 years and in most place more recently than that," Ferguson says.

In his research, Ferguson looked at cases reported as violent deaths throughout the prehistoric record. He found that 15 percent to 25 percent of deaths that many anthropologists and archeologists say were the result of war may reflect cherry-picking the most violent cases, which are contradicted by broad surveys of all archaeological sites.

"Individual killing is not the same as war on social groups," says Ferguson. "War leaves physical traces that archaeologists can find. When and where it began is very different in different places around the world, but there are stretches of even thousands of years when there are no clear signs of war."

Part of the reason for the debate, Ferguson says, is that the evidence used to identify prehistoric warfare – weapons, art and cave paintings, defensive structures and skeletal remains – are often ambiguous and difficult to interpret. Careful examination of all evidence typically finds no strong indication of war in early remains, which changes to clear signs of war in later periods.

He disputes the belief of many scholars that humans may have inherited their genetic makeup from their chimpanzee cousins millions of years ago. After examining every reported chimpanzee killing, Ferguson, who is writing a book on the subject, believes that war among chimps was not an evolved evolutionary strategy but rather a response to human contact and disturbances.

So why did war become so common in more recent archaeological finds? Ferguson says that preconditions that made war more likely became far more widespread, including social hierarchy, a more sedentary existence, a growing regional population, valuable resources and the establishment of boundaries. These conditions have sometimes worsened with severe environmental changes, he says.

Ferguson, who also studies contemporary war, brutal civil wars around the world and U.S. wars in Iraq and Afghanistan, agrees with anthropologist Margaret Mead that "warfare is only an invention, not a biological necessity," but does he not see war ending.

"Anthropologists think about prospects for war in the long term," Ferguson says. "If the idea that war is part of human nature is not scientifically supported, alternative futures open up. If more people work for prevention, the eventual eradication of war is a definite theoretical possibility."

Source: Rutgers University [December 04, 2018]

Scientists are painting the clearest picture yet of what life may have been like for Neanderthals living in Southern France some 250,000 years ago, and to do it, they're using an unlikely day-to-day record of what their environment was like—their teeth.

Teeth may be an important new resource for understanding the lives of our extinct relatives, said Daniel Green, a postdoctoral fellow at the Forsyth Institute, an affiliate of Harvard Dental School of Medicine [Credit: Kris Snibbe/Harvard University]

A team of researchers showed that examining the teeth of Neanderthal infants could yield insight into nursing and weaning behavior as well as winter and summer cycles. The study even found evidence that the Neanderthals had been exposed to lead—the earliest such exposure ever recorded in any human ancestor.

The study from researchers Daniel Green, a postdoctoral fellow at the Harvard-affiliated Forsyth Institute; Tanya Smith, a former Harvard professor now at Griffith University in Australia; and Icahn School of Medicine at Mount Sinai researchers Christine Austin and Manish Arora, who is also a former postdoctoral fellow at the Harvard T.H. Chan School of Public Health, was recently published in Science Advances.

"Humans are very different from other apes," said Green, one of the first authors of the study. "We are curious to understand what made us different in evolutionary history, and a lot of people have looked to the climate to understand those differences.

"Obviously, we are changing the climate today, but in the past the climate was shaping us, and a number of theories suggest that changes in the seasonal availability of water drove us to take one part of our behavioral repertoire—stone-tool-making—and use that much more frequently," he continued.

"But that idea is hard to test … because we don't know what rainfall was like 2, 3, or 4 million years ago. It turns out teeth are a really good way of addressing this problem because they grow in rings, like a tree, but those rings are formed every day."

And much like tree rings, he said, changes in the environment—such as winters and summers—are recorded in the chemical composition of teeth, giving modern scientists a window into the seasonal patterns with which Neanderthals contended.

The study builds partly on research Green conducted several years ago as part of his Ph.D., in which he raised a flock of 10 sheep at Harvard's Concord Field Station.

"What we did was collect 700 gallons of glacial melt water from Montana, so we could give it to the sheep and contrast it with Boston water as a way to create these artificial, experimental seasons," Green said. "Everything was carefully controlled—we were measuring their body chemistry in real time, their environmental chemistry in real time, and we built a computational and statistical model to predict, based on measurements we can make in the teeth, what the seasons were like when they were living."

The technique proved to be so effective, Green said, that not only could he identify the seasonal differences between the two water supplies, he was even able to spot short-lived environmental changes like snowstorms.

"Everything was working, but we were seeing one small blip," he said. "When we went back to the animals' lives … it turned out that there had been two big snow storms that were not a planned part of the experiment. The sheep had eaten snow from the ground, and that was reflected in their tooth chemistry. So the system worked so well that it actually ended up re-creating storm events, and teaching us about our own experiment."

Informed by these findings, and adding barium and lead measurements to the oxygen isotope analyses in teeth, Smith and her international team of archaeologists, biological anthropologists, Earth scientists, and public health specialists were able to identify a similar seasonal pattern in Neanderthal teeth.

"We can see that one of the Neanderthals was born in the spring and weaned from mother's milk in the fall, and we can see they were exposed to lead a number of discrete times in the winter," Green said. "That was a striking result, and there is still a lot of mystery about it. We don't actually know where that lead comes from … but we do know that later, during the Roman period and onward, there were lead mines in the area, so it's possible that lead in the ground had contaminated some water or food sources."

What is known, Green said, is that teeth may be an important new resource for understanding the lives of our extinct relatives.

"The oxygen analysis used in this study is a new type that has been used only a few times previously," Green said. "So to validate that work, and show we can pick out these seasonal cycles from Neanderthal teeth, we looked at some of the analyses I had done for my Ph.D., used them to validate the technique, and we then applied it to Neanderthals."

Going forward, Green hopes to trace the source of lead exposure found in the Neanderthal teeth, but also believes the finding may set other scientists on the path to searching for similar exposures in other early populations. The ability to track these exposures in teeth opens the door to using the technique in contemporary populations as well, he said.

"If people are saying they have been exposed to lead or that their water isn't clean, we could go to that community and look at the teeth children are losing naturally," Green said. "We could use this type of analysis to understand who has been exposed, by how much, and what kind of interventions are needed to deal with those issues."

Green also said he hopes to see researchers apply the technique to other early human ancestors, particularly those in Africa, in an effort to understand the environmental challenges they faced as they evolved.

"I didn't expect that the very detailed and technical geochemical work I did would apply to such a salient question about the lives of Neanderthals and in Europe, so this has been very rewarding for me," he said. "It's very exciting to have these cousins who are so closely related to us, and who contributed to our DNA, and to see these very precise moments in their lives and place them in some sort of environmental and seasonal context."

Author: Peter Reuell | Source: Harvard University [December 04, 2018]

Why do people go to war when the consequences of warfare are so dramatic? Scholars have suggested that the motivations for participating in war either lie in the individual rewards warriors receive (to the victor goes the spoils) or because group members coerce them to participate for fear of punishment. Understanding the factors that motivate warriors to join war parties sheds light on some of the most fundamental aspects of human nature: How our ability to cooperate is linked to our most destructive tendencies.

In a new study, a team of researchers examined the social composition of raiding parties and their relationship to marriage alliances in an Amazonian tribal society, the Waorani of Ecuador [Credit: Pete Oxford/australscope]

In a new study, a team of researchers examined the social composition of raiding parties and their relationship to marriage alliances in an Amazonian tribal society, the Waorani of Ecuador. The Waorani formerly practiced lethal raiding, or small-scale warfare, as part of their social fabric. The anthropologists spoke in detail with tribal members about their raiding histories in an attempt to understand what drives individuals to participate in acts of war. Theirs is one of only a handful of datasets in the world with detailed information about what warfare looks like in small-scale societies prior to the intervention of the state.

They found that Waorani are actively joining raids with people who could provide access to ideal marriage partners for themselves as well as their children. Additionally, subtle coercion from in-laws appears to be a factor in joining raids. The relationships built through raiding resulted in meaningful bonds between the men, which could shed light on the evolution of friendship.

"A big debate in anthropology is what warfare and raiding groups look like in small-scale societies. Arguments have always been about this nice band of brothers--literally brothers, uncles, fathers all fighting side-by-side with one another," said Shane Macfarlan, assistant professor of anthropology at the University of Utah and lead author of the study. "But sometimes, kin are not enough. Warfare is about alliance building, relationships with other people where there might be something else to gain by fighting with one another--like marriage partners."

The Waorani

The Waorani are indigenous Ecuadorians from the lowlands of the Amazon Rainforest made up of 2,000 individuals today. When people of Euro-American descent first made contact with members of the tribe in 1958, the population consisted of 500 individuals residing in four mutually hostile territories. Within the territories, Waorani lived in neighborhoods of longhouses, called nanicabo. Each neighborhood was separated by a one- to two-days walk, and each nanicabo was separated by a 30- to 60-minute walk.

The Waorani formerly practiced lethal raiding, or small-scale warfare, as part of their social fabric [Credit: Kleverenrique/WikiCommons]

For the Waorani, the ideal marriage partners are bilateral cross cousins--for example a man's mother's brother's daughter or his father's sister's daughter. One of the ways to make alliances is through raiding. Lethal raiding was quite common amongst the Waorani; when an individual decided to raid, he would convince followers to join him.

"The benefit of making an alliance outside of your direct kin is that it expands your social universe for getting the things that you need, and one of the things that people need in all societies is mating partners," said Macfarlan.

Between 2000 and 2001, co-authors Jim Yost, Pam Erickson of University of Connecticut and Steve Beckerman of Pennsylvania State University interviewed almost all of the Waorani population aged 49 years or older--65 women and 55 men. The researchers collected detailed genealogical information from multiple generations, and cross-referenced the data with existing Waorani genealogies. They also collected raid histories that included the men who participated, the organizer, the victims, and the rationale for the attack. The researchers used marriages and births to establish a timeline of the raids. From 1917 to 1970, there were 550 raid reports. The researchers consolidated them into 49 separate raids that involved 81 people.

In-laws, brothers and marriage

Macfarlan and senior author Stephen Beckerman analyzed the make-up of the raiding groups and the raiders' marriage histories. If the "bands of brothers" model holds, then the raiders should include mostly direct ancestors or descendants of each other, known as lineal kin. If the groups were strategic alliances, then the individuals should consist of men who can provide marriage opportunities for each other--genetically related, but outside of lineal kinship. Because the researchers needed to be able to distinguish cousins, they only used individuals for whom they had grandparents' information. They analyzed the social composition of the 49 raids, including the 1041 individual relationships that emerged from the 81 men who participated.

Co-author Jim Yost (right) with a Waorani man discussing Waorani  territory during the data collection component of the project [Credit: Jim Yost]

Although males had a plenty of lineal kin to choose from for forming raiding parties, they selectively raided with non-lineal kin. They also found that men raided more frequently with men who were generically related to them, but from different lineages--the ideal marriage exchange partners. Indeed, the raiding alliances resulted in marriages for both the raiders, and for the raiders' children.

Yet another motivation to join raiding parties seemed to include some coercion. Macfarlan found that sometimes men got married first, then raided more frequently with his in-laws.

While scholars have typically assumed that warfare was either about individual rewards or coercion we find that this is a two-way street. "Sometimes people go to war to find alliance partners that gives them access to marriage opportunities, but other times guys get married first and then these marriage ties are leveraged to coerce people into warfare."

Evolution of friendship

Humans for the most part have three kinds of relationships: kinship, marriage and friendship. Traditionally, anthropologists only considered kinship and marriage as important. Recent interest has looked into the evolution of friendship itself. A common feature of friendship across cultures is that it promotes cooperation between people who are neither are kin nor our lovers, with our friends providing us with benefits that kin and lovers cannot. One context where friendship is extremely important is helping us deal with conflict from other people and groups, known as the Alliance Hypothesis.

The study's findings provide evidence for this hypothesis, Macfarlan said.

"The act of killing another human is a really traumatic act, which causes people to share something in common psychologically that establishes trust and fosters things like friendships," said Macfarlan.

The study was published in the journal Proceedings of the Royal Society B.

Source: University of Utah [December 03, 2018]

The Dental Anthropology Group of the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) has just published a paper on dental histology in the journal Comptes Rendus PALEVOL, in which a comparison is made for the first time between the sample from the Sima de los Huesos site, in Atapuerca (Burgos), and dental samples from the Neanderthal site of Krapina, in Croatia, as well as with different modern human populations.

The Dental Anthropology Group of the CENIEH has published the first dental histology study of Sima de los Huesos, which reinforces the close relationship between this European Middle Pleistocene population  and the species Homo neanderthalensis [Credit: CENIEH]

This is a comparative study centering on the canines, in which certain dental pieces from Homo antecessor were included, whose results make it clear that the Pleistocene populations at Atapuerca already showed the pattern considered typically Neanderthal in their enamel and dentine volumes.

“The teeth from Sima de los Huesos exhibit large coronal and root dentine dimensions, as well as thin enamel. This histological pattern has traditionally been considered a distinctive trait of the Neanderthals, and it has allowed them to be distinguished both from other groups and from modern humans”, according to Cecilia García Campos, lead author of the paper.

Further, the results of this study might support an early appearance of this highly characteristic dental trait, which had been observed as early as 800,000 years ago in Homo antecessor, and maintained in later groups during the Middle Pleistocene.

The fossils found at Sima de los Huesos were initially considered to belong to the taxon Homo heidelbergensis, a species which populated Europe before the Neanderthals, so named from the mandible found in the locality of Heidelberg (Germany).

Nevertheless, a study led by Juan Luis Arsuaga, Centro Mixto UCM-ISCIII de Evolución y Comportamiento Humanos de Madrid, published in 2014 in the journal Science, raised doubts about this assignment, and suggested removing the population at Sima from this taxon because of its evident similarities to Homo neanderthalensis.

Later, two genetic studies of Sima de los Huesos, published in the journal Nature in 2014 and 2016, underpinned this decision by showing that these hominins belonged to the Neanderthal evolutionary lineage because of their close relationship to the ancestors of the Neanderthals.

“The dental histology results obtained for the individuals at la Sima de los Huesos support the close relationship there must have been between the Middle Pleistocene hominins at Atapuerca and the later Neanderthal groups living in Europe”, adds García Campos.

Source: CENIEH - Centro Nacional de Investigación sobre la Evolución Humana [December 01, 2018]

About 56 million years ago, on an Earth so warm that palm trees graced the Arctic Circle, a mouse-sized primate known as Teilhardina first curled its fingers around a branch.

Teilhardina brandti likely resembled a modern tarsier, a small primate native to Southeast Asia. A lower jaw  from a tarsier is pictured at top with a lower jaw from Teilhardina brandti for comparison  [Credit: Florida Museum/Kristen Grace]

The earliest-known ancestor of modern primates, Teilhardina's close relatives would eventually give rise to today's monkeys, apes and humans. But one of the persistent mysteries about this distant cousin of ours is where it originated.

Teilhardina species quickly spread across the forests of Asia, Europe and North America, a range unparalleled by all other primates except humans. But where did its journey begin?

New research shows that Teilhardina brandti, a species found in Wyoming, is as old or older than its Asian and European relatives, upending the prevailing hypothesis that Teilhardina first appeared in China. Teilhardina's origins, however, remain a riddle.

"The scientific conclusion is 'We just don't know,'" said Paul Morse, the study's lead author and a recent University of Florida doctoral graduate. "While the fossils we've found potentially overturn past hypotheses of where Teilhardina came from and where it migrated, they definitely don't offer a clearer scenario."

What is clear, Morse said, is that T. brandti had a wide variety of features, some of which are as primitive as those found in Teilhardina asiatica, its Asian cousin, previously thought to be the oldest species in the genus.

To make this determination, Morse studied 163 teeth and jaws in the most comprehensive analysis of T. brandti to date.

Teeth contain a treasure-trove of information and often preserve better than bone, thanks to their tough enamel. They can reveal clues about an animal's evolutionary past, its size, diet and age as an individual and in geological time.

The unusual tooth sockets in UF specimen 333700 upended the hypothesis that Teilhardina brandti was a younger  species in the genus. The sockets closely resemble those in Teilhardina asiatica, thought to be  the most primitive Teilhardina species [Credit: Florida Museum/Paul Morse]

Primate teeth have particularly distinct structures that are immediately recognizable to the trained eye, said Jonathan Bloch, study co-author and curator of vertebrate paleontology at the Florida Museum of Natural History.

"Identifying differences between primate teeth is not so different from a biker recognizing that a Harley is different from a scooter or an art critic evaluating whether an image was created by Picasso or Banksy," he said. "In detail, they are very different from each other in specific, predictable ways."

While Teilhardina bones are very rare in the fossil record, its teeth are more plentiful - if you know how to find them. Bloch's team of paleontologists, Morse included, have spent years combing the surface of Wyoming's Bighorn Basin on hands and knees and then packing out 50-pound bags of soil to a river to screen wash. The remaining bits of bones and teeth - which can be smaller than a flea - are examined under a microscope back at the museum.

This painstaking search has built up the dental record of T. brandti from a single molar - used to first describe the species in 1993 - to hundreds of teeth, providing a broad look at the primate's population-level variation.

Still, Morse and Bloch were unprepared for the peculiar variation exhibited by specimen UF 333700, a jagged piece of jaw with T. brandti teeth.

"Jon and I started arguing about the alveoli" - empty tooth sockets - "and how they didn't look right at all," said Morse, now a postdoctoral researcher at Duke University. "By the end of the day, we realized that specimen completely overturned both the species definition of T. asiatica and part of the rationale for why it is the oldest Teilhardina species."

Studies based on a small number of teeth simply missed the diversity in Teilhardina's physical characteristics, Morse said.

"There's likely a tremendous amount of variation in the fossil record, but it's extremely difficult to capture and measure when you have a small sample size," he said. "That's one of the reasons collecting additional fossils is so important."

Teilhardina americana, whose jaw is pictured here, has been reclassified as a new genus, Bownonomys,  as a result of Morse’s analysis [Credit: Florida Museum/Zach Randall & Rose Roberts]

The analysis also reshuffled the Teilhardina family tree, reducing the number of described species from nine to six and reclassifying two species as members of a new genus, Bownomomys, named for prominent vertebrate paleontologist Thomas Bown.

But the precise ages of Teilhardina species are still impossible to pinpoint and may remain that way.

Teilhardina appeared during the geological equivalent of a flash in the pan, a brief 200,000-year period known as the Paleocene-Eocene Thermal Maximum, or PETM. This era was characterized by a massive injection of carbon into the Earth's atmosphere, which sent global temperatures soaring. Sea levels surged by 220 feet, ecosystems were overhauled and the waters at the North Pole warmed to 74 degrees.

Scientists can use the distinct carbon signature of the PETM to locate this period in the rock record, and carbon isotopes in teeth can also be used to identify fossil animals from the era.

But among Teilhardina fossil sites across the globe, only Wyoming has the uninterrupted, neatly demarcated layers of rock that allow paleontologists to hone in on more precise dates.

"The humblest statement would be to say that these species are essentially equivalent in age," Bloch said. "Determining which came earlier in the PETM probably surpasses the level of resolution we have in the rock record. But what we can say is that the only place where you can really establish where Teilhardina appears in this climate event with confidence is in the Bighorn Basin."

As the Earth warmed, plants and animals expanded their ranges northward, returning south as temperatures cooled at the end of the PETM.

"This dance of plants and animals with climate change happened over vast landscapes, with forests moving from the Gulf Coast to the Rocky Mountains in just a few thousand years," Bloch said.


Teilhardina likely tracked the shifts in its forest habitats across the land bridges that then connected North America, Greenland and Eurasia, he said.

"Teilhardina is not throwing its bag over its shoulder and walking," he said. "Its range is shifting from one generation to the next. Over 1,000 years, you get a lot of movement, and over 2,000-3,000 years, you could easily cover continental distances."

While it was well-suited to Earth's hothouse environment, Teilhardina disappeared with the PETM, replaced by new and physically distinct primates. It's a sobering reminder of what can happen to species - including humans - during periods of swift climatic changes, Bloch said.

"A changing planet has dramatic effects on biology, ecosystems and evolution. It's part of the process that has produced the diversity of life we see today and mass extinctions of life that have happened periodically in Earth's history," Bloch said. "One of the unexpected results of global warming 56 million years ago is that it marks the origin of the group that ultimately led to us. How we will fare under future warming scenarios is less certain."

The findings were published in the Journal of Human Evolution.

Source: Florida Museum of Natural History [November 29, 2018]

Some things you learn in school turn out not to be true, for example that there are just five senses or three states of matter. Now cutting-edge research has added to the list by proving the mitochondria (the power sources in our cells) comes from both our parents and not – as biology students are taught – just from our mothers.

Mitochondria are tiny, free-floating organelles inside cells [Credit: Northwestern University]

The research, published in the Proceedings of the National Academy of Sciences, showed conclusively that, in three unrelated families, mitochondria from the father's sperm had been passed to the children over several generations. Overturning scientific understanding about this fundamental "truth", opens the possibility for better treatment of mitochondrial disorders, which blight many families with devastating disease.

Mitochondria convert the sugars, fats and proteins that we eat into the molecules our cells use to power themselves. So when they go wrong, the result is often catastrophic, resulting in lifelong problems or even the death of an affected baby in the womb.

MELAS syndrome, for example, begins in early childhood and results in seizures and dementia. Kearns-Sayre syndrome causes problems with sight and hearing, potentially leaving the sufferer blind and deaf.

Most of a cell's DNA is contained in its nucleus but mitochondria sit separately inside the cell and have their own DNA. This is because mitochondria are thought to have started as separate organisms, which entered early cells about 1.45 billion years ago and never left. They reproduce themselves and move from one generation to another by "hitching a lift" in the egg.

Mitochondria are the power sources of a cell [Credit: Sebastian Kaulitzk/Shutterstock]

During fertilisation, the father's sperm transfers his DNA into an egg, but few or none of the sperm's mitochondria get in. If any do, then there are mechanisms designed to destroy them. The new research found that, in a small number of families, the mitochondria from the father that found its way into the egg were not destroyed, though we don't yet know enough to say why. There was also some evidence this mitochondrial DNA from the father may have then been copied as the fertilised egg grew into an embryo even more than that from the mother.

There's a chance that previous research may have also found examples of mitochondria being passed on from fathers but that these results were discounted and assumed to be the result of sample contamination. But with ever-increasing technological advances, cheaper and more in-depth DNA analysis is possible. So it's likely that more and more cases will now be reported.

This work could affect scientists studying the movement of humans around the planet. Human mitochondrial DNA tends to alter very little over time because even tiny changes are often fatal so aren't passed on to future generations. This means a person's mitochondrial DNA is likely to be very similar to that of their distant ancestors and other people from their ethnic group.

So by studying mitochondrial DNA in different populations, scientists have also been able to follow how these groups have moved around the world and even to identify a potential common female ancestor for all humans, known as "mitochondrial Eve". All of this work has, however, been based on the "fact" that mitochondria pass down the female line only, something we now know to be wrong.


The most significant implications of these findings are staggering, because a better understanding of how mitochondria are passed on gives us a much better chance of developing treatments for mitochondrial disorders. It may even be possible to encourage properly functioning mitochondria to multiply inside a fertilised egg at the expense of the broken ones.

Any treatment would likely be controversial, because it would involve influencing someone's DNA in a way that would be inherited by subsequent generations. But the only other current treatment is equally controversial and involves inserting the nucleus from a fertilised egg into a donor egg containing normal mitochondria. This is often described as producing "three-parent babies" and is not permitted in most countries, although the first such baby was born in April 2016. So manipulating the parent's mitochondria instead may be seen as more preferable.

When it comes to our use of mitochondrial DNA to study human evolution and migration, the rarity of the cases identified by the new study means it won't significantly impact our understanding in this area. But if further research suggests that the inheritance of fathers' mitochondrial DNA is more common, our whole understanding of human migration may need to be adjusted.

Author: Michael J Porter | Source: The Conversation [November 29, 2018]

Researchers from the Max-Planck-Institute for the Science of Human History and the University of Helsinki have analyzed the first ancient DNA from mainland Finland. As described in Nature Communications, ancient DNA was extracted from bones and teeth from a 3,500 year-old burial on the Kola Peninsula, Russia, and a 1,500 year-old water burial in Finland. The results reveal the possible path along which ancient people from Siberia spread to Finland and Northwestern Russia.

Artistic impression of an ancient fisherman from Bolshoy Oleni Ostrov [Credit: Kerttu Majander]

Researchers found the earliest evidence of Siberian ancestry in Fennoscandia in a population inhabiting the Kola Peninsula, in Northwestern Russia, dating to around 4,000 years ago. This genetic ancestry then later spread to populations living in Finland. The study also found that people genetically similar to present-day Saami people inhabited areas in much more southern parts of Finland than the Saami today.

For the present study, genome-wide genetic data from 11 individuals were retrieved. Eight individuals came from the Kola Peninsula, six from a burial dated to 3,500 years ago, and two from an 18th to 19th century Saami cemetery. "We were surprised to find that the oldest samples studied here had the highest proportion of Siberian ancestry," says Stephan Schiffels, co-senior author of the study, of the Max Planck Institute for the Science of Human History.

The other three individuals analyzed for the study came from a water burial in Levänluhta, Finland. Levänluhta is one of the oldest known burials in Finland in which human bones have been preserved. The bodies were buried in what used to be a small lake or a pond, and this seems to have contributed to exceptionally good preservation of the remains.

Siberian ancestry persists today

The study compared the ancient individuals not only to each other, but also to modern populations, including Saami, Finnish and other Uralic language speakers. Among modern European populations, the Saami have the largest proportion of this ancient Siberian ancestry. Worldwide, the Nganasan people, from north Siberia, have the largest proportion of ancient Siberian ancestry.

Location of archaeological sites with material used in this study [Credit: Michelle O'Reilly; Lamnidis, Majander et al. 2018]

"Our results show that there was a strong genetic connection between ancient Finnish and ancient Siberian populations," says Thiseas Lamnidis, co-first author of the study, "suggesting that ancient populations from Siberia may have also shared a subsistence strategy, languages and/or cultural behaviours with Bronze Age and Iron Age Finns, despite the large geographical distance."

Ancient Finnish populations possibly lived a mobile, nomadic life, trading and moving over a large range, with far-reaching contacts to other populations.

People found in Levänluhta, Finland, most resemble modern-day Saami

The researchers found that the population in Levänluhta was more closely related to modern-day Saami people than to the non-Saami Finnish population today.

Artistic impression of the Levänluhta water burial site [Credit: Kerttu Majander]

"People closely related to the Saami inhabited much more southern regions of Finland than the Saami do today," explains Kerttu Majander, co-first author, of the University of Helsinki and the Max Planck Institute for the Science of Human History. Interestingly, a recent linguistic study suggested that the place names around Levänluhta trace back to Saami languages.

"This is the first exploration of ancient DNA from Finland and the results are very interesting," states Schiffels. "However more ancient DNA studies from the area will be necessary to better understand whether the patterns we've seen are representative of Finland as a whole."

The study was conducted as a collaboration between the SUGRIGE-project (Universities of Helsinki and Turku), and the Max Planck Institute for the Science of Human History. The archaeological materials and expertise were provided by the Peter the Great Museum of Anthropology and Ethnography (Kunstkamera) and the Levänluhta-project with the Finnish Heritage Agency.

Source: Max-Planck-Institute for the Science of Human History [November 27, 2018]