Strigolactones also help plant roots form symbiotic relationships with microorganisms that allow the plant to absorb nutrients from the soil. These two factors have led to agricultural interest in using strigolactones to control the growth of weeds and root parasites, as well as improving nutrient uptake.

These root-extruding compounds don’t come without risks. They also stimulate germination of witchweeds and broomrapes, which can cause entire crops of grain to fail, making thorough research essential prior to commercial development. Scientists are still learning about the physiological roles played by this diverse group of hormones in plants. Until recently, manufacturing pure strigolactones for scientific study has been difficult and too costly for agricultural use.

“Our work provides a unique platform to investigate strigolactone biosynthesis and evolution, and it lays the foundation for developing strigolactone microbial bioproduction processes as alternative sourcing,” said corresponding author Yanran Li, a UC Riverside assistant professor of chemical and environmental engineering.

Together with co-corresponding author Kang Zhou at National University Singapore, Li directed a group that inserted plant genes associated with strigolactone production into ordinary baker’s yeast and nonpathogenic Escherichia coli bacteria that together produced a range of strigolactones.

Producing strigolactones from yeast turned out to be very challenging. Although engineered yeast is known to modify the strigolactone precursor, called carlactone, it could not synthesize carlactone with any of the specific genes used by the researchers.

“This project started in early 2018, yet for over 20 months there was basically no progress. The gatekeeping enzyme DWRF27 is not functional no matter how we try in yeast,” Li said. “Kang developed a microbial consortium technique to produce a Taxol precursor in 2015 and that inspired this wonderful collaboration.”

The team turned toward E. coli, which had already been shown capable of producing carlactone. The carlactone it produced, however, was unstable and could not be further modified by engineered E. coli into any strigolactones. Li’s group managed to optimize and stabilize the carlactone precursor.

To their delight, when the yeast and bacteria were cultured together in the same medium, the E. coli and yeast worked as a team: E. coli made carlactone, and the yeast transformed it into various final strigolactone products. The method also produced enough strigolactones to extract and study. Using this platform, the group identified the function of multiple strigolactone biosynthetic enzymes, showing that sweet orange and grape have the potential to synthesize orobanchol-type strigolactones.

The team also engineered microbe metabolism to boost strigolactone production threefold to 47 micrograms per liter, enough for scientific study. Though commercial production of strigolactones is still a long way off, the new method for biosynthesizing them from a yeast-bacterium consortium will help scientists learn more about this important group of plant hormones, especially the enzymes involved.

Enzymes are protein catalysts and are responsible for modification of carlactone by yeast. Because carlactone is unstable, it cannot be purchased from commercial sources. As a result, many plant scientists have difficulty studying new enzymes that may work to transform carlactone into strigolactones.

“The new yeast-bacterium co-culture provides a convenient way for scientists to complete such works because the bacterium makes carlactone in situ,” Zhou said. “With discovery of more enzymes and optimization of the microbial consortium, we can manufacture strigolactones in quantity in the future.”

Li and Zhou were joined in the research by Sheng Wu, Anqi Zhou, and Alex Valenzuela of UC Riverside; and Xiaoqiang Ma at the Singapore-MIT Alliance for Research and Technology. The paper, “Establishment of strigolactone-producing bacterium-yeast consortium,” is available here.

“Something didn’t seem right, but I didn’t know what to say at the time. I just went on to the next question of the assessment,” said Bullock, now a professor emerita at the University of Missouri Sinclair School of Nursing. “We stopped her labor and sent her home, but I will bet my last dollar I sent her back to an abusive relationship, and it sparked my interest in helping other nurses assist battered women. What we didn’t know at the time was the impact violence had on the baby.”

Bullock helped implement the Domestic Violence Enhanced Perinatal Home Visits (DOVE) program in rural Missouri, which empowered safety planning and reduced domestic violence for hundreds of abused pregnant women. After learning from home health visits that many of the abused women had up to nine different romantic partners during and following pregnancy, Bullock conducted a study to examine the impact of multiple father figures on the cognitive development of the newborn infants.

After administering neurodevelopmental tests during home visits three, six and 12 months after birth, she was surprised to find the infants of women who had only one male partner who abused them had worse cognitive outcomes compared to infants of women with multiple male partners, only some of whom were abusive.

“The findings highlight the variety of ways the multiple father figures may have been helping the mom support her baby, whether it was providing food, housing, childcare or financial benefits,” Bullock said. “For the women with only one partner who abused them, the infant’s father, the father may not have provided any physical or financial support or played an active role in the child’s life. It can be difficult for busy, single moms struggling to make ends meet to provide the toys and stimulation their infants need to reach crucial developmental milestones.”

Bullock added that infants coming from homes with domestic violence often go on to have worse academic outcomes in school due to neurodevelopmental lags and a higher risk for a variety of health issues, including gastrointestinal distress, trouble eating and sleeping, as well as stress and illness.

“When nurses are visiting homes to check in on pregnant women and their developing babies, we want them to be trained in recognizing the warning signs of potential intimate partner violence,” Bullock said. “I still think back to 1983 when I sent that lady back home into a terrible situation, and I am passionate about making sure I can help nurses today not make the same mistake I made.”

“Children exposed to intimate partner violence: Impact of multiple father figures” was recently published in Maternal Child Health Journal. Funding for the study was provided by the National Institutes of Nursing Research. The study involved collaborators from Johns Hopkins University and University of Virginia.

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The findings will be published online Sept. 17 in JAMA Network Open.

“We wanted to understand the spectrum of allergies to the new vaccines and understand what was causing them,” said the study’s senior author, Kari Nadeau, MD, PhD, the Naddisy Foundation Professor in Pediatric Food Allergy, Immunology, and Asthma.

The study analyzed 22 potential allergic reactions to the first 39,000 doses of Pfizer and Moderna COVID-19 vaccines given to health care providers at Stanford soon after the vaccines received emergency use authorization from the Food and Drug Administration.

Most of those in the study who developed reactions were allergic to an ingredient that helps stabilize the COVID-19 vaccines; they did not show allergies to the vaccine components that provide immunity to the SARS-CoV-2 virus. Furthermore, these allergic reactions occurred via an indirect activation of allergy pathways, which makes them easier to mitigate than many allergic responses.

“It’s nice to know these reactions are manageable,” said Nadeau, who directs the Sean N. Parker Center for Allergy and Asthma Research at Stanford. “Having an allergic reaction to these new vaccines is uncommon, and if it does happen, there’s a way to manage it.”

The study’s lead author is former postdoctoral scholar Christopher Warren, PhD, now an assistant professor at Northwestern University Feinberg School of Medicine.

The research also suggests how vaccine manufacturers can reformulate the vaccines to make them less likely to trigger allergic responses, Nadeau said.

Delivery of protein-making instructions

The mRNA-based COVID-19 vaccines provide immunity via small pieces of messenger RNA that encode molecular instructions for making proteins. Because the mRNA in the vaccines is fragile, it is encased in bubbles of lipids — fatty substances — and sugars for stability. When the vaccine is injected into someone’s arm, the mRNA can enter nearby muscle and immune cells, which then manufacture noninfectious proteins resembling those on the surface of the SARS-CoV-2 virus. The proteins trigger an immune response that allows the person’s immune system to recognize and defend against the virus.

Estimated rates of severe vaccine-related anaphylaxis — allergic reactions bad enough to require hospitalization — are 4.7 and 2.5 cases per million doses for the Pfizer and Moderna vaccines, respectively, according to the federal Vaccine Adverse Event Reporting System. However, the federal system doesn’t capture all allergic reactions to vaccines, tending to miss those that are mild or moderate.

For a more complete understanding of allergic reactions to the new vaccines — how common they are, as well as how severe — the research team examined the medical records of health care workers who received 38,895 doses of mRNA-based COVID-19 vaccines at Stanford Medicine between Dec. 18, 2020, and Jan. 26, 2021. The vaccinations included 31,635 doses of the Pfizer vaccine and 7,260 doses of the Moderna vaccine.

The researchers searched vaccine recipients’ medical records for treatment of allergic reactions and identified which reactions were linked to the vaccines. Twenty-two recipients, 20 of them women, had possible allergic reactions, meaning specific symptoms starting within three hours of receiving the shots. The researchers looked for the following symptoms in recipients’ medical records: hives; swelling of the mouth, lips, tongue or throat; shortness of breath, wheezing or chest tightness; or changes in blood pressure or loss of consciousness. Only 17 of the 22 recipients had reactions that met diagnostic criteria for an allergic reaction. Three recipients received epinephrine, usually given for stronger anaphylaxis. All 22 fully recovered.

Of the 22 recipients, 15 had physician-documented histories of prior allergic reactions, including 10 to antibiotics, nine to foods and eight to nonantibiotic medications. (Some recipients had more than one type of allergy.)

The researchers performed follow-up laboratory testing on 11 individuals to determine what type of allergic reaction they had, as well as what triggered their allergy: Was it one of the inert sugar or lipid ingredients in the bubble, or something else in the vaccine?

The study participants underwent skin-prick tests, in which a clinician injected small amounts of potential allergens — the lipids, sugars (polyethylene glycol or polysorbates) or entire vaccine — into the skin. Skin-prick testing detects allergic reactions mediated by a form of antibody known as immunoglobin E, or IgE; these reactions are generally associated with the severest allergies.

None of the recipients reacted on skin-prick tests to the inert ingredients in the vaccines, and just one recipient’s skin reacted to the whole COVID-19 vaccine. Follow-up blood tests showed that the vaccine recipients did not have significant levels of IgE antibodies against the vaccine ingredients.

Since the skin tests did not explain the mechanism of recipients’ allergic reactions, the investigators proceeded to another type of diagnostic test. Vaccine recipients provided blood samples for tests of allergic activation of immune cells known as basophils. The blood samples from 10 of the 11 participants showed a reaction to the inert ingredient polyethylene glycol (PEG), which is used in both the Pfizer and Moderna vaccines. In addition, all 11 recipients had basophil activation in response to the whole mRNA vaccine when it was mixed with their own basophils.

All 11 subjects had high levels of IgG antibodies against PEG in their blood; IgG antibodies help activate basophils under some conditions, and this finding suggests the individuals were likely sensitive to PEG before receiving their vaccines.

“What’s important is what we didn’t find, as much as what we did find,” Nadeau said. “It does not seem that the mRNA itself causes the allergic reactions.”

In addition, the data suggest that reactions to the COVID-19 vaccines were generally not the most severe form of allergic reaction, which is good news in terms of vaccine safety, she said. Allergic reactions mediated by IgG and basophils can be managed with antihistamines, fluids, corticosteroids and close observation, meaning that many individuals who have had a reaction to their first vaccine dose can safely receive a second dose under medical supervision.

PEG is widely used as a stabilizer in household products, cosmetics and medications, with women more likely to be exposed to large quantities of the substance, possibly explaining why more vaccine allergies have been seen among women. (Repeated exposures to a substance can sometimes sensitize the immune system and provoke allergies.) Because most reactions were to PEG rather than the vaccine’s active ingredients, it is likely that vaccine manufacturers can reformulate the vaccines with different stabilizers that are less likely to cause allergies, Nadeau said.

The study’s other Stanford authors are research assistants Theo Snow, Alexandra Lee, Mihir Shah, Eric Smith, Evan Do and Iris Chang; Andra Blomkalns, MD, professor of emergency medicine; Brooke Betts, PharmD, clinical pharmacist; medical student Anthony Buzzanco; graduate student Joseph Gonzalez; Sharon Chinthrajah, MD, associate professor of medicine and of pediatrics; lab manager Diane Dunham; Grace Lee, MD, professor of pediatrics; Ruth O’Hara, MD, PhD, dean of research and professor of psychiatry and behavioral sciences; Helen Park, PharmD, clinical pharmacist at the Veterans’ Affairs Palo Alto Health Care System; Lisa Schilling, RN, MPH, vice president of quality, safety and clinical effectiveness and chief quality officer with Stanford Health Care; Sayantani Sindher, MD, clinical associate professor of medicine and of pediatrics; Deepak Sisodiya, PharmD, administrative director of pharmacy services at Stanford Health Care; Mindy Tsai, DMSc, senior research scientist in pathology; and Stephen Galli, MD, professor of pathology and of microbiology and immunology.

Nadeau is a member of the Stanford Institute for Immunology, Transplantation and Infection; senior fellow at the Stanford Woods Institute for the Environment; a fellow at the Stanford Center for Innovation and Global Health; and member of the Bill Lane Center for the American West at Stanford. Nadeau and Galli are members of Stanford Bio-X. Nadeau, O’Hara and Galli are members of the Stanford Cardiovascular Institute. Nadeau and O’Hara are members of the Wu Tsai Neurosciences Institute at Stanford. O’Hara, Nadeau, Chinthrajah, Grace Lee, Sindher and Galli are members of the Stanford Maternal and Child Health Research Institute. Galli is a member of the Stanford Cancer Institute.

Researchers from the Swiss Institute of Allergy and Asthma Research at the University of Zurich; the Department of National Heart and Lung Institute at Imperial College London; and the Centre in Allergic Mechanisms of Asthma, London, also contributed to this research.

The research was supported by the Asthma and Allergic Diseases Cooperative Research Centers (grant U19AI104209), the National Institutes of Health (grant R01AI140134), the National Institute of Allergy and Infectious Disease SARS Vaccine study (grant UM1AI10956508), the Parker Foundation, the Crown Foundation and the Sunshine Foundation.

The researchers studied the impact of deleting specific proteins in immune cells that were responsible for controlling the ability of cells to silence or switch off genes.

They were surprised to find that one population of ‘sentinel’ immune cells was affected by deletion of a component of the machinery, causing the cells to disappear from skin and lungs completely. This suggests that drugs which inhibit this component to treat diseases, such as cancer, could have unintended consequences for the immune system.

The research was led by Dr Yifan Zhan, Dr Yuxia Zhang, Mr Shengbo Zhang, Dr Michael Chopin, Professor Stephen Nutt and colleagues, and was published in Science Immunology.

A complex issue

The research team studied the role of the polycomb repressive complex 2 (PRC2) in frontline responder immune cells.

Dr Chopin said the PRC2 was responsible for ‘switching off’ genes, including in immune cells, which was essential for maintaining their numbers and normal function.

“Our laboratory investigates gene regulation, or the molecular processes inside cells that control how and when the genes encoded by our DNA are used,” he said.

“We studied the function of the PRC2 in two immune cell populations that form the first line of defence against infection. These cells provide a critical immune barrier to the external environment, protecting the skin and lungs from microbial invasion.”

The research team removed two components of the complex, an enzyme called EZH2 and a structural protein called Suz12, to see how it impacted immune cell development, populations and function.

Deleting EZH2 had no impact on the biology or function of either cell population — with the cells still able to respond to viral infection effectively.

“We surprised to find that the immune cells were largely unaffected by deleting EZH2,” Dr Chopin said.

In contrast, when Suz12 was deleted, certain populations of macrophages, such as those that reside in our skin and lungs, completely disappeared.

“These tissue-resident macrophages are responsible for detecting and ridding the body of a variety of infiltrating bacteria and virus-infected cells, and alerting the body that it is under attack by stimulating the production of inflammatory signals,” Dr Chopin said.

“Tissue-resident macrophages have the unique property of being able to independently maintain their numbers throughout adult life. Our research highlights a key role for Suz12 and PRC2 in controlling this regulatory program of these immune cells.”

Unexpected effects

Professor Nutt said it was important to understand the potential knock-on effects of drugs that interfere with the proteins that switch genes off.

“PRC2 has been implicated in many cancers, such as lymphoma. There is significant work being undertaken around the world to develop drugs that target components of the complex to treat cancer.

He said at least one drug already approved for treating a rare type of sarcoma inhibited components of the complex.

“We need to study more closely whether drugs that inhibit the function of EZH2 and Suz12 could have unintended consequences for the immune system,” he said.

On the flipside, Professor Nutt said, it was also important to understand what redundancies exist that might prevent drugs having their desired effect.

“The current belief is that inhibiting EZH2 will dampen the immune response, for example if you are wanting to treat immune or inflammatory diseases,” Professor Nutt said. “Our research shows that, at least with these specific frontline immune cells, that are active early in infection and trigger other elements of the immune system, that is unlikely to be the case.”

Professor Nutt said the research was part of the team’s broader focus on gene regulation at a molecular level.

“The normal function of the cells in our bodies relies on each cell’s ability to use the appropriate combination of genes from the tens of thousands of genes encoded in our DNA in the right place and at the right time,” he said.

“The molecular controls that prevent genes from being used are essential to life.”

The research was supported by the Australian National Health and Medical Research Council, WEHI Innovation Grant and the Victorian Government.

In Singapore, the prevalence of childhood SLE has been reported to be 14.2 per 100,000 children, while that of adult SLE is 40 per 100,000 adult population. Cognitive dysfunction is common in patients with SLE. Earlier studies have shown that 25% of SLE patients were found to have cognitive dysfunction, compared to 7.3% in age- and gender-matched healthy individuals. Common cognitive dysfunction demonstrated by SLE patients includes impairment of simple reaction time, sustained and selected attention, memory search, working memory, and short-term memory for learnt associations, which result in reduced health-related quality of life and a negative impact on vocational capability.

The neural mechanism leading to cognitive dysfunction in patients with SLE remains unknown. Researchers at the NUS Yong Loo Lin School of Medicine attempted to unravel such mechanisms by adopting non-invasive diffusion magnetic resonance imaging (MRI) to study the brains of SLE patients, particularly the white matter, coupled with computerised neuropsychological assessment. White matter lies beneath the grey matter cortex in the human brain and comprises millions of bundles of nerve fibres that transmit signals to different brain regions.

Led jointly by Associate Professor Juan Helen Zhou, from the Centre for Sleep and Cognition and Deputy Director for the Centre for Translational Magnetic Resonance Research at NUS Medicine, and Associate Professor Anselm Mak, a clinician scientist with the Division of Rheumatology at the Department of Medicine, the group investigated brain white matter free water changes in SLE. White matter free water refers to water molecules surrounding white matter in the brain that are able to diffuse unhindered

In the paper published in Rheumatology, a Tier 1 journal in the field of Rheumatology with the Oxford University Press, they compared the free-water signals in SLE patients without clinically overt neuropsychiatric manifestations with a group of matched healthy participants using the novel free water diffusion MRI technique. They discovered that patients with SLE had significantly higher white matter free water than their healthy counterparts, suggesting possible microvascular degradation and/or inflammation. Such increases in free water were significantly related to cognitive dysfunction, especially sustained attention, as well as cumulative dosage of medical steroids.

“The clinical implications of the study would indicate to physicians that steroids should be judiciously prescribed, aiming for the lowest possible dose for the shortest possible duration. While systemic use of steroids will continue to be the mainstay of treatment for moderate to severe SLE-related inflammation, there are other therapeutic options that could produce similar results: these should be considered first in order to reduce steroid use or shorten the necessary course,” said Assoc Prof Anselm Mak.

He also added that there are other SLE manifestations that could be symptomatically treated without the prescription of steroids. For example, non-steroidal anti-inflammatory drugs could be used for milder inflammation, topical treatment for hair loss and topical analgesics for oral ulcers.

SLE patients on long-term steroid treatments should also be regularly assessed and monitored for cognitive dysfunction. The researchers noted that the use of the Automated Neuropsychiatric Assessment Matrix (ANAM), which has been validated for use in adult and paediatric SLE patients, is an efficient and effective tool for these regular evaluations.

Further research will have to be conducted to find out if a reduction of steroid dosage would be related to reduction of white matter free water that would lead to an improvement to cognitive function in SLE patients. The team is also keen to further investigate the mechanism of the increase in white matter free water underlying cognitive decline using multimodal imaging, behavioral, and blood assays in SLE patients longitudinally.

Under the guidance of Mechanical Engineering Professor Hod Lipson, the “Digital Food” team of his Creative Machines Lab has been building a fully autonomous digital personal chef. Lipson’s group has been developing 3D-printed foods since 2007. Since then, food printing has progressed to multi-ingredient prints and has been explored by researchers and a few commercial companies.

“We noted that, while printers can produce ingredients to a millimeter-precision, there is no heating method with this same degree of resolution,” said Jonathan Blutinger, a PhD in Lipson’s lab who led the project. “Cooking is essential for nutrition, flavor, and texture development in many foods, and we wondered if we could develop a method with lasers to precisely control these attributes.”

In a new study published Sept. 1, 2021, by npj Science of Food, the team explored various modalities of cooking by exposing blue light (445 nm) and infrared light (980 nm and 10.6 μm) to chicken, which they used as a model food system. They printed chicken samples (3 mm thick by ~1in² area) as a test bed and assessed a range of parameters including cooking depth, color development, moisture retention, and flavor differences between laser-cooked and stove-cooked meat. They discovered that laser-cooked meat shrinks 50% less, retains double the moisture content, and shows similar flavor development to conventionally cooked meat.

“In fact, our two blind taste-testers preferred laser-cooked meat to the conventionally cooked samples, which shows promise for this burgeoning technology,” Blutinger said.

While Lipson and Blutinger are excited about the possibilities of this new technology, whose hardware and software components are fairly low-tech, they note that there is not yet a sustainable ecosystem to support it. Lipson states that “what we still don’t have is what we call ‘Food CAD,’ sort of the Photoshop of food. We need a high level software that enables people who are not programmers or software developers to design the foods they want. And then we need a place where people can share digital recipes, like we share music.”

Still, says Blutinger, “Food is something that we all interact with and personalize on a daily basis — it seems only natural to infuse software into our cooking to make meal creation more customizable.”

Video on Robots that Cook: precision cooking with multiwavelength lasers: https://www.youtube.com/watch?v=jct3f92rIOE&t=42s

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Twelve newly sequenced ancient Japanese genomes show that modern day populations do indeed show the genetic signatures of early indigenous Jomon hunter-gatherer-fishers and immigrant Yayoi farmers — but also add a third genetic component that is linked to the Kofun peoples, whose culture spread in Japan between the 3^rd and 7^th centuries.

Rapid cultural transformations

The Japanese archipelago has been occupied by humans for at least 38,000 years but Japan underwent rapid transformations only in the last 3,000 years, first from foraging to wet-rice farming, and then to a technologically advanced imperial state.

The previous, long-standing hypothesis suggested that mainland Japanese populations derive dual-ancestry from the indigenous Jomon hunter-gatherer-fishers, who inhabited the Japanese archipelago from around 16,000 to 3,000 years ago, and later Yayoi farmers, who migrated from the Asian continent and lived in Japan from around 900 BC to 300 AD.

But the 12 newly sequenced ancient Japanese genomes — which came from the bones of people living in pre- and post-farming periods — also identify a later influx of East Asian ancestry during the imperial Kofun period, which lasted from around 300 to 700 AD and which saw the emergence of political centralisation in Japan.

Shigeki Nakagome, Assistant Professor in Psychiatry in Trinity College Dublin’s School of Medicine, led the research, which brought together an interdisciplinary team of researchers from Japan and Ireland. Professor Nakagome said:

“Researchers have been learning more and more about the cultures of the Jomon, Yayoi, and Kofun periods as more and more ancient artefacts show up, but before our research we knew relatively little about the genetic origins and impact of the agricultural transition and later state-formation phase.”

“We now know that the ancestors derived from each of the foraging, agrarian, and state-formation phases made a significant contribution to the formation of Japanese populations today. In short, we have an entirely new tripartite model of Japanese genomic origins — instead of the dual-ancestry model that has been held for a significant time.”

Genomic insights into key Japanese transformations

In addition to the overarching discovery, the analyses also found that the Jomon maintained a small effective population size of around 1,000 over several millennia, with a deep divergence from continental populations dated to 20,000-15,000 years ago — a period which saw Japan become more geographically insular through rising sea-levels.

The Japanese archipelago had become accessible through the Korean Peninsula at the beginning of the Last Glacial Maximum, some 28,000 years ago, enabling movement between. And the widening of the Korea Strait 16,000 to 17,000 years ago due to rising sea-levels may have led to the subsequent isolation of the Jomon lineage from the rest of the continent. These time frames also coincide with the oldest evidence of Jomon pottery production.

“The indigenous Jomon people had their own unique lifestyle and culture within Japan for thousands of years prior to the adoption of rice farming during the subsequent Yayoi period. Our analysis clearly finds them to be a genetically distinct population with an unusually high affinity between all sampled individuals — even those differing by thousands of years in age and excavated from sites on different islands,” explained Niall Cooke, PhD Researcher at Trinity. “These results strongly suggest a prolonged period of isolation from the rest of the continent.”

The spread of agriculture is often marked by population replacement, as documented in the Neolithic transition throughout most of Europe, with only minimal contributions from hunter-gatherer populations observed in many regions. However, the researchers found genetic evidence that the agricultural transition in prehistoric Japan involved the process of assimilation, rather than replacement, with almost equal genetic contributions from the indigenous Jomon and new immigrants associated with wet-rice farming.

Several lines of archaeological evidence support the introduction of new large settlements to Japan, most likely from the southern Korean peninsula, during the Yayoi-Kofun transition. And the analyses provide strong support for the genetic exchange involved in the appearance of new social, cultural, and political traits in this state-formation phase.

“The Japanese archipelago is an especially interesting part of the world to investigate using a time series of ancient samples given its exceptional prehistory of long-standing continuity followed by rapid cultural transformations. Our insights into the complex origins of modern-day Japanese once again shows the power of ancient genomics to uncover new information about human prehistory that could not be seen otherwise,” added Dan Bradley, Professor of Population Genetics in Trinity’s School of Genetics and Microbiology, who co-led the project.