Category Archives: Human Genetics

Verona High School senior Christopher Lakin has made it to the final round of the Breakthrough Junior Challenge, though he did not win the Popular Vote part of the global science video contest. That honor went to a video on cryptography by Branko Malaver-Vojvodic of Peru. As we reported earlier this month, Lakins video is on the role of quantum physics in making solar power cells more efficient.

Lakin is now one of just 16 teenagers from all over the worlddown from more than more than 11,000 registrantswho are competing to win a grand prize valued at $400,000. On November 3, we will learn whether Lakin has succeeded in his effort to win $50,000 for Alexander Cali, the VHS teacher who inspired his thinking, another $100,000 for a new science lab at VHS and $250,000 to pay for his college education.

Over the next month, Lakins video, and those of the other contestants, will be reviewed by a committee that includes Salman Khan, the founder and CEO of Khan Academy; author and educator Lucy Hawking; Dr. Mae Jemison, science literacy expert, former astronaut, and principal, 100 Year Starship; retired NASA Astronaut Scott Kelly; Nima Arkani-Hamed, a professor of physics at the Institute for Advanced Study and Breakthrough Prize in Fundamental Physics Laureate; Rachel Crane, space and science correspondent for CNN; Huda Zoghbi, professor of pediatrics and professor of neuroscience and molecular and human genetics at Baylor College of Medicine and Breakthrough Prize in Life Sciences Laureate; Ijad Madisch, CEO and co-founder of ResearchGate; Jason Silva, a host on National Geographic Channel Television; Pete Worden, chairman of the Breakthrough Prize Foundation and executive director, Breakthrough Starshot; Esther Wojcicki, founder of the Palo Alto High Media Arts Center; and Terence Tao, professor of mathematics at UCLA and Breakthrough Prize in Mathematics Laureate.

All Lakin can do now is wait for the results.

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Lakin Named Finalist In Global Science Video Contest - My veronanj

It took almost 15 years for scientists to sequence and publish a complete accounting of the human genetic code the 3 billion base pairs along the double strands of DNA that serve as a blueprint for the bodys functions and pass traits from parents to offspring.

Now, approximately 15 years after the human genome was first sequenced, current discoveries represent just the beginning when it comes to the genetic origins of disease and the ever-expanding number of individual human genome sequences available to study. Researchers currently utilize what are called genome-wide association studies (GWAS) to discover hundreds of associations between genetic variations and specific diseases and disorders shared among individuals. But to date, very few researchers have fully explored how correlations between genes and disease may be different in women and men.

Dr. Hongyu Zhao, an internationally known expert in the field of statistical genetics, has collected preliminary data to suggest that genetic pathways may relate to some diseases differently in women and men.

Many human traits and diseases have sex or gender differences, and many diseases have a significant genetic component, said Zhao, Department Chair and Ira V. Hiscock Professor of Biostatistics at Yale School of Medicine. However, most analyses of genetic data assume the same effect for both women and men or use a methodology that is not calibrated to detect potential sex differences.

With a grant from WHRY, Zhao and his team are now building upon new statistical methods they have developed to detect such differences. What is key to Dr. Zhaos work is that the methods developed by his group will have more statistical power to explore sex differences than other methods.

For example, the published results in the literature suggest sex differences in the genetic basis for Alzheimers disease, an area he is eager to pursue further. His work will seek to better define which areas of the genome are contributing to Alzheimers disease differently in women and men and will potentially identify new genes involved in Alzheimers disease for further study. By better understanding first and foremost which genes contribute to Alzheimers disease, researchers will be better able to understand how these genes are functioning in women and men, and ultimately, use this insight to inform treatment or prevention strategies.

Members in Dr. Zhaos lab will work with him to inspect large databases (in particular, the UK Biobank featuring health and genetic data on more than 500,000 participants in the United Kingdom) and focus on diseases and traits with a significant impact on the health of women. In addition to Alzheimers disease, the project will include coronary artery disease and autoimmune disease.

The researchers will then develop sex-specific genetic risk models and build a foundation to support an application for external funding to further develop and apply these methods to transform our understanding of disease.

We seek to establish statistical methods tailored to detect sex differences in genetic contributions to human traits and diseases, which will potentially provide candidate genes and proteins for further study in relation to disease, Zhao said. Follow-up studies may improve our ability to identify high-risk individuals for prevention and screening, ultimately improving the effectiveness of disease treatment.

Originally posted here:
The Genetic Origins of Sex Differences in Disease - Yale News

(more about Power Words)

cancerAny of more than 100 different diseases, each characterized by the rapid, uncontrolled growth of abnormal cells. The development and growth of cancers, also known as malignancies, can lead to tumors, pain and death.

Cas9An enzyme that geneticists are now using to help edit genes.It can cut through DNA, allowing it to fix broken genes, splice in new ones or disable certain genes. Cas9 is shepherded to the place it is supposed to make cuts by CRISPRs, a type of genetic guides. The Cas9 enzyme came from bacteria. When viruses invade a bacterium, this enzyme can chop up the germs DNA, making it harmless.

cellThe smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall. asyeasts, molds, bacteria and some algae, are composed of only one cell.

clinicaltrialA research trial that involves people.

CRISPRAn abbreviation pronounced crisper for the term clustered regularly interspaced short palindromic repeats. These are pieces of RNA, an information-carrying molecule. They are copied from the genetic material of viruses that infect bacteria. When a bacterium encounters a virus that it was previously exposed to, it produces an RNA copy of the CRISPR that contains that virus genetic information. The RNA then guides an enzyme, called Cas9, to cut up the virus and make it harmless. Scientists are now building their own versions of CRISPR RNAs. These lab-made RNAs guide the enzyme to cut specific genes in other organisms. Scientists use them, like a genetic scissors, to edit or alter specific genes so that they can then study how the gene works, repair damage to broken genes, insert new genes or disable harmful ones.

disorder(in medicine) A condition where the body does not work appropriately, leading to what might be viewed as an illness. This term can sometimes be used interchangeably with disease.

DNA(short for deoxyribonucleic acid) Along, double-stranded and spiral-shaped molecule inside most living cells that carries genetic instructions. It is built on a backbone of phosphorus, oxygen, and carbon atoms. In all living things, from plants and animals to microbes, these instructions tell cells which molecules to make.

engineerA person who uses science to solve problems. As a verb, to engineer means to design a device, material or process that will solve some problem or unmet need.

gene(adj. genetic) A segment of DNA that codes, or holds instructions, for a cells production of a protein. Offspring inherit genes from their parents. Genes influence how an organism looks and behaves.

geneticHaving to do with chromosomes, DNA and the genes contained within DNA. The field of science dealing with these biological instructions is known as genetics. People who work in this field are geneticists.

hemoglobinA molecule that binds to oxygen in the blood, carrying it around to tissues.

immune(adj.) Having to do with the immunity. (v.) Able to ward off a particular infection.Alternatively, this term can be used to mean an organism shows no impacts from exposure to a particular poison or process. More generally, the term may signal that something cannot be hurt by a particular drug, disease or chemical.

insightThe ability to gain an accurate and deep understanding of a situation just by thinking about it, instead of working out a solution through experimentation.

multiplemyelomaThis cancer starts in a type of white blood cells known as plasma cells. Part of the immune system, they help guard the body from germs and other harmful substances.

muscleA type of tissue used to produce movement by contracting its cells, known as muscle fibers. Muscle is rich in protein, which is why predatory species seek prey containinglots of this tissue.

mutation(v. mutate) Some change that occurs to a gene in an organisms DNA. Some mutations occur naturally. Others can be triggered by outside factors, such as pollution, radiation, medicines or something in the diet. A gene with this change is referred to as a mutant.

nerveA long, delicate fiberthat transmits signalsacross the body of an animal. An animals backbone contains many nerves, some of which control the movement of its legs or fins, and some of which convey sensations such as hot, cold or pain.

neuronAn impulse-conducting cell. Such cells are found in the brain, spinal column and nervous system.

oxygenA gas that makes up about 21 percent of Earth's atmosphere. All animals and many microorganisms need oxygen to fuel their growth (and metabolism).

pharmaceuticalsMedicines, especially prescription drugs.

plasma (in medicine) The colorless fluid part of blood.

proteinA compoundmade from one or more long chains of amino acids. Proteins are an essential part of all living organisms. They form the basis of living cells, muscle and tissues; they also do the work inside of cells. Among the better-known, stand-alone proteins are thehemoglobin (in blood) and the antibodies (also in blood) that attempt to fight infections. Medicines frequently work by latching onto proteins.

redblood cellColored red by hemoglobin, these cells move oxygen from the lungs to all tissues of the body. Red blood cells are too small to be seen by the unaided eye.

retinaA layer at the back of the eyeball containing cells that are sensitive to light and that trigger nerve impulses that travel along the optic nerve to the brain, where a visual image is formed.

RNAA molecule that helps read the genetic information contained in DNA. A cells molecular machinery reads DNA to create RNA, and then reads RNA to create proteins.

sarcomaA family of more than 70 cancers that begin in bones or in connective tissues.

technologyThe application of scientific knowledge for practical purposes, especially in industry or the devices, processes and systems that result from those efforts.

therapy(adj. therapeutic) Treatment intended to relieve or heal a disorder.

variantA version of something that may come in different forms. (ingenetics) A gene having a slight mutation that may have left its host species somewhat better adapted for its environment.

wombAnother name for the uterus, the organ in mammals in which a fetus grows and matures in preparation for birth.

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Genetics CRISPR enters its first human trials - Science News for Students

For more than a century, the humble and ubiquitous fruit fly has helped scientists shed light on human genetics, disease, and behavior. Now a new study by the University of Miami researchers reveals that the tiny, winged insects have an innate time- and color-dependent preference for light, raising the intriguing possibility that our own color choices depend on the time of day.

In a study published in the journal Nature on Wednesday, the researchers made two unexpected discoveries. First, they found that, given a choice, fruit flies are drawn to green light early in the morning and late in the afternoon, when they are most active, and to red, or dim light, in midday, when like many humans, they slow down to eat and perhaps take a siesta.

Much to the researchers' surprise, they also found that fruit flies, Drosophila melanogaster, demonstrate a "robust avoidance" for blue light throughout the day, a finding that turns a decades-long assumption on its head. Previous experiments dating back to the 1970s determined that fruit flies are attracted to blue light, the main driver for the circadian clock, or the genetic 24-hour timekeeper that controls the lives of humans and most other animals.

"If given a choice, the fact that flies would not choose blue is surprising, but the most surprising thing, which is relevant not just to flies, but to color preference in general, is the fact that color preference changes with time of day," said senior author Sheyum Syed, assistant professor of physics, who conceived and designed the study with post-doctoral student Stanislav Lazopulo. "This finding opens the possibility that human color preference also changes with the time of day, which may explain why it's been so difficult to nail down how color guides our choices."

Added study coauthor James D. Baker, a research assistant professor of biology who helped supervise the study, "Stan has shown that these animals have a very clear preference for different colors of light at different times of day that's repeatable day to day, individual to individual, genotype to genotype. Our research community didn't have any idea that was happening."

Four years ago, while a graduate student in Syed's lab, Lazopulo set out to determine how Drosophila would respond to the colored light they would experience at their leisure in nature. If given a choice, what light would they choose? Would there be a pattern? Would their choices be guided by the circadian clock that guides all organisms?

With assistance from his brother, Andrey, he created an elaborate set of behavioral experiments that involved placing hundreds of single flies into tiny multicolored tubes that had a stopper on one end, food at the other end, and three distinct "rooms"--one green, one red, and one blue--that the insects could freely navigate.

Then he recorded their movements around the clock, through 12 hours of constant light and 12 hours of complete darkness, for as many as two weeks at a time. When Lazopulo reviewed the initial computer analysis of the recordings, he thought he had miscoded the computer program.

"They actually don't like blue light. They run away from blue light," he said. "It was absolutely an unexpected result. Based on all the previous knowledge we were not expecting to have such a preference for green, an avoidance for blue, and such robust patterns in this behavior."

But neither the computer program, nor the video, nor his eyes were flawed. During the day, the flies consistently avoided the blue zones, even when their food was placed in one. Under those circumstances, they would make brief incursions into a blue zone, but only to feed.

In contrast, the flies began to occupy the green zones about two hours after the lights came on in the morning. By midday, their preference for green and their activity diminished, with about half the population split between the green and red, or dim, zones. Then, about an hour before the lights turned off, the flies returned to the green zones and their more active state. Later, during the lights-off phase, the flies randomly distributed themselves across the three zones, indicating, the researchers said, "that light is essential for generating the observed pattern."

Lazopulo and Syed, whose lab studies fruit fly behavior to better understand animal sleep, grooming, and color preferences, attributed the disparate results from earlier studies to improvements in long-term tracking methods and to the differences in the design of the experiments, particularly the difference in the time and conditions that the flies had to choose their color preference.

Past researchers, Syed said, tested Drosophila's color preference by releasing the flies into the bottom of a T-shaped vial and giving them 30 seconds to decide which arm of the T to exit--one with a green light and the other with a blue. The UM researchers suspect the flies chose blue under duress, as "an avoidance response to a noxious stimulus."

But now they know that, at their leisure and under more natural conditions, Drosophila prefers green, like the leaves of the fruit trees where, to the frustration of many a farmer, they like to lay their eggs.

Through what Baker called a "tour de force set of experiments" that included a series of genetic manipulations, the researchers also discovered that the fruit fly's color-driven behavior doesn't depend just on its visual system, as previously documented, but also on light-sensitive cells in the insect's abdomen that sense blue. Their internal clock guides the decision to stay in green or choose dim light in the middle of the day. Delete the clock genes, and the fruit flies always stay in the green, never switching to dim light in midday.

But even without the clock, they still avoid blue, thanks to those abdominal cells that signal independently of the clock genes.

What this means for humans remains to be seen. But 110 years after embryologist Thomas Hunt Morgan began breeding fruit flies to confirm how genetic traits are inherited, UM researchers have shown there's still much to learn from the common pest that has evolved into the most studied and written about the animal on the planet. In all, 10 scientists have earned six Nobel Prizes for their groundbreaking biological discoveries using fruit flies, whose genetic and physiological makeup is far simpler than humans, yet very similar.

In 1933, Morgan earned the first Nobel for discovering the role chromosomes play in heredity; in 2017, a trio of scientists earned the latest one, for isolating the circadian clock genes that control the rhythm of nearly every organism's daily life--not just in the brain, but in almost every cell in the body.

2018 NatureWorldNews.com All rights reserved. Do not reproduce without permission.

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Study Gives the Green Light to the Fruit Fly's Color Preference - Nature World News

A doctors race against time to find a cure to his rare disease

Dr. David Fajgenbaum was a third-year medical student when he suddenly fell ill and was diagnosed with Castleman disease. Determined not to give up on life, the doctor relapsed four times before he took it upon himself to find a cure for his disease. Fajgenbaum sits down with Fox News Dr. Manny Alvarez to talk about his miraculous journey of survival.

An otherwise healthy medical student wasnt going to let a rare disease stop him from living life to the fullest.

Dr. David Fajgenbaum was in his third year of medical school when he got so sick he had to be hospitalized for five months. Doctors told him his liver, kidney and other organs were shutting down.

At 25 years old, Fajgenbaum was diagnosed with Castleman disease, a condition that acts like a cross between cancer and an autoimmune disorder. According to the National Organization for Rare Disorders (NORD) there are about 5,000 people diagnosed with Castleman disease in the U.S. each year, making it roughly as common as Lou Gehrigs disease, also known as ALS.

People who haveCastleman disease can experience such things asflu-like symptoms and abdominal pain to the complete failure of multiple organ systems.

The diagnosis took about 11 weeks, and most of that time I was in the intensive care unit, Fajgenbaum told Fox News. I had a retinal hemorrhage and went blind in my left eye. I gained about 70 pounds of fluid and I was so sick that I had my last rites read to me right around the time the diagnosis was made.

TEXAS GIRL WHO CONTRACTED BRAIN-EATING AMOEBA DIES, FAMILY SAYS

Having a rare disease often means limited information and few if any treatment options.

When Fajgenbaum was diagnosed with Castleman disease there was only one drug currently approved by the U.S. Food and Drug Administration (FDA), butthat he relapsed on, leaving him with no other therapy choices.

I promised my dad, my sisters, and my now wife that I would dedicate the rest of my life, however long that may be, to trying to cure this disease

When I relapsed on the only drug in development and my doctor told me that there was nothing coming down the pipeline and there were no promising leads, that's when I promised my dad, my sisters, and my now wife that I would dedicate the rest of my life, however long that may be, to trying to cure this disease, Fajgenbaum said.

In a little more than three years,Fajgenbaum relapsed fourtimes, nearly missing death each time.

Yet with the help of chemotherapy keeping his disease at bay, Fajgenbaum was able to finish medical school and propose to his college sweetheart. But instead of starting a residency, he founded theCastleman Disease Collaborative Network (CDCN), to drive forward research internationally but also to begin conducting laboratory work.

We've made a lot of progress in the last seven years since I started the CDCN and we've invested about $1 million into research, which has led to an additional $7 million in external funding from the government and from non-profits, Fajgenbaum said.

With experts collaborating together from around the globe and a relatively limited amount of funding Fajgenbaum and his organization identified the first novel drug target in 25 years.

That drug target that we identified, I actually identified it in my lab using my own samples, said Fajgenbaum, who is also an assistant professor of medicine in the division of Translational Medicine & Human Genetics at the University of Pennsylvania. I started myself on this drug Sirolimus about five and a half years ago and I've been in remission ever since.

Fajgenbaum was the first patient to try Sirolimus as a treatment for Castleman disease, but he and his team will test the treatment in a clinical trial scheduled to begin at the University of Pennsylvania later this year.

Fajgenbaum, now 34 years old, with a wife and 1-year-old daughter, chronicled his journey to a cure in a new book, Chasing My Cure: A Doctors Race to Turn Hope into Action.

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I wrote this book because there's lessons that I've learned about life, lessons about living from nearly dying five times, lessons that hopefully will inspire people to turn their hopes into action and create silver linings in the midst of tough times, Fajgenbaum said.

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Medical student with rare disease finds possible cure from studying his own blood samples - Fox News

UK-based Oxford Nanopore has obtained a licence to CRISPR-Cas9 IP for nanopore sequencing, a third-generation approach used in the sequencing of biopolymers.

Oxford Nanopore, which specialises in DNA/RNA sequencing technology, announced the non-exclusive licence agreement with biotech company Caribou Biosciences yesterday, September 19.

Caribou was founded by scientists from the University of California, Berkeley, including CRISPR pioneer Jennifer Doudna.

Gordon Sanghera, CEO of Oxford Nanopore, said: The Cas9 technique will enable users to select and isolate the regions of the genome they are most interested in, including those not available to existing methods, ready for rapid analysis using our long-read, real-time sequencing technology.

According to the company, Cas9 enrichment with Oxford Nanopore sequencing enables scientists to cost-effectively sequence targeted regions that were not accessible previously.

Sanghera added: The entire library preparation process takes less than two hours so if combined with our portable sequencer MinION, this has the potential to open up fast-turnaround, near-sample testing in new ways.

In October last year, Amgen invested 50 million ($66 million) in Oxford Nanopore, as part of Amgens focus on using human genetics to deliver new medicines to patients.

Earlier in 2018, Oxford Nanopore announced it had raised 100 million from global investors, to be used to support the companys next phase of commercial expansion, including a new high-tech manufacturing facility in Oxford.

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Oxford Nanopore, CRISPR-Cas9, Caribou Biosciences, Jennifer Doudna, gene-editing, genetics, nanopore, University of California,

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Oxford Nanopore signs CRISPR licence - Life Sciences Intellectual Property Review

Overnutrition during early infancy can have adverse health consequences later in life. Although researchers have known this for quite some time, the explanations have been hard to come by. At Baylor College of Medicine, the laboratory of Dr. Robert A. Waterland has provided a new answer to this old question.

Its been known for several decades that mice that are overnourished during the suckling period remain overweight and will be prone to disease for their entire lives. Particularly, they have problems regulating their blood sugar levels, said corresponding author Dr. Robert A. Waterland, professor of pediatrics nutrition at the USDA/ARS Childrens Nutrition Research Center at Baylor College of Medicine and Texas Childrens Hospital and of molecular and human genetics at Baylor.

Previous studies also have shown that patients with Type-2 diabetes have altered DNA methylation, the addition of methyl chemical groups, in their insulin-producing pancreatic islets. These alterations have been linked to islet malfunction and the onset of diabetes, but how they occur remains a mystery.

Looking to shed light on this important topic, Waterland and his colleagues investigated whether early postnatal overnutrition could alter epigenetic development in murine pancreatic Islets of Langerhans, which produce insulin and other hormones.

Epigenetics refers to molecular mechanisms that determine which genes will be turned on or off in different cell types. Think of ones DNA as the computer hardware, and epigenetics as the software that determines what the computer can do. Epigenetics works by adding or removing chemical tags on genes to mark those that should be used. DNA methylation is one of the better studied tags and plays an important role in development.

The researchers worked with two groups of mice, one was overnourished during infancy and the other was not and represented the control group.

Adjusting litter size during the suckling period provides a natural means to overnourish mouse pups, said Waterland, who is a member of the Dan L Duncan Comprehensive Cancer Center at Baylor. Normal size litters have about 10 mice, and served as our control group. The overnourished group came from moms whose litters were reduced to only four pups each. These pups get an all you can eat buffet and become overweight by the time of weaning.

But weight was not the only difference between the two groups of pups. The researchers applied genome-scale DNA methylation profiling to islets of overnourished and control mice at both 21 days (weaning) and 180 days after birth (considered middle-age for mice).

The results revealed that islets from control mice tended to gain DNA methylation as they aged. Compared to controls, however, islets of overnourished mice showed increased DNA methylation right at weaning. Unexpectedly, there was a substantial overlap between the DNA methylation profile of middle-aged controls and that of the much younger 21 day old overnourished mice.

By the age of weaning, islets of overnourished mice show an epigenetic profile resembling that of much older mice, Waterland said.

Our interpretation is that postnatal overnutrition causes accelerated epigenetic aging in the islets. Since the ability to regulate blood sugar declines with age, this premature epigenetic aging may help explain how overnutrition during infancy increases the risk of diabetes later in life.

Diabetes is a serious, pervasive health concern worldwide. According to a 2017 report from the Centers for Disease Control and Prevention, 9.3 percent of the U.S. population about 30 million people are afflicted with the condition, which increases the risk of serious health complications including premature death, vision loss, heart disease, stroke, kidney failure and amputation of toes, feet or legs.

In these days of escalating pediatric overnutrition and obesity, we urgently need to understand the adverse consequences of overnutrition in human infancy. I believe that optimizing nutrition during these critical periods of development will prove to be an effective approach to prevent adult disease, Waterland said.

Read all the details of this work in the journal Environmental Epigenetics.

Other contributors to this work include first author Ge Li, Tihomira D. Petkova, Eleonora Laritsky, Noah Kessler, Maria S. Baker and Shaoyu Zhu, all at Baylor.

This project was supported by grants from NIH/NIDDK (1R01DK081557), USDA (CRIS 3092-5-001-059) and from the Thrasher Research Fund (NR-0136).

By Ana Mara Rodrguez, Ph.D.

Originally posted here:
Early postnatal overnutrition sets the body on a fast-track to aging - Baylor College of Medicine News

Native Americans have been visiting Calvert Island off the Canadian coast for more than 10,000 years. (Credit: Pacific Northwest Sailing/Shutterstock)

Humans have long found comfort on Calvert Island, just off the coast of mainland British Columbia. For millennia, they have climbed the islands rocky outcrops, walked through its rainy conifer forests, and waded through its chilly intertidal pools to collect crabs, mussels, and other marine life.

There, in 2014, a group of Canadian researchers uncoveredhuman footprintspressed into a prehistoric layer of soil. The footprints, 29 in total, are the oldest found in North America. They suggest an intimate scene in which, 13,000 years ago, at least three people may have hopped out of a boat onto the damp shore. One person appears to have slipped as the group walked toward drier land. The footprints also speak to a much larger and contested storythe tale of the humans who first set foot in North America.

North and South America were relatively lonely places for our species 13,000 years ago. The continents were the last major landmasses in the world to be populated byHomo sapiens. But the explanation of how and when this peopling happened has needed to be heavily revised in the last two decades.

This field is bonkers right now, says anthropological geneticist Jennifer Raff of the University of Kansas. I think theres a new important paper coming out every three or four months. Indeed, no tidy, new framework has arisen to take the place of older theories. Instead, new data, including genetic findings, continue to complicate the story of how these continents came to be peopled.

As San Diego State University archaeologist Todd Braje puts it, We know less about the peopling of the New World now than we did 20 years ago. (Or, as Raff puts it, we know more but are less united in a single consensus model.)

But such complications could be a good thing. The lack of consensus has pushed researchers to delve into evidence on the continental shelf and other unexpected places as they craft new narratives. In the process, non-Native scientists are also considering a long-neglected but critical perspective in this discussion: that of Native Americans.

Not so long ago, many researchers believed they had an adequate explanation for the peopling of the Americas. A single theory dominated much of the 20th centurys thinking on this question.

In 1932, geologist and archaeologist Edgar B. Howard got wind of noteworthy mammalian fossils coming from a site called Blackwater Draw in New Mexico. A construction crew had exposed an extensive deposit of bison and mammoth bones, and there Howard found spear points and other human artifacts scattered among the remains of extinct megafauna, including mammoths, camels, and bison.

Howards discoveries came at a time when researchers were only beginning to appreciate that humans were in the Americas during the last ice age, which ended around 10,000 years ago. In the years to follow, archaeologists would unearth sleek, fluted spear points, just like the ones found at Clovis, across North America. These artifacts came to be known asClovis pointsand were the ice age equivalent of the spread of Coca-Cola or baseball caps, as archaeologist Tom Dillehay wrote in his bookThe Settlement of the Americas. The Clovis-style spear points thus came to be linked to people whom archaeologists considered the first Americans.

Where did the people responsible for these artifacts come from? It was long a commonplace belief among anthropologists that ancestral Native Americans descended from people living in Asia who crossed into the Americas over a now-submerged open tundra bridging Russia and Alaska, the Bering Land Bridge, also known as Beringia.

From there, these people were thought to have traversed a narrow passage between glaciers covering Alaska and Canada that only opened up about 13,500 years ago. The prevalence of Clovis-style spear points, which generally date between 13,250 and 12,800 years old, suggested that the first people in the Americas spread quickly after their arrival. Scientists broadly referred to this narrativeencompassing not just the cultural artifacts but also the time frame and land bridgeas the Clovis-first model.

The theory hit a steady stream of challenges in subsequent years, but most werent taken too seriously. More than 500 archaeological sites in North and South America had been claimed to have been older than Clovis, and each of them had a Warhol-esque 15 minutes of fame until some fatal flaw was detected, says Jim Adovasio, director of archaeology at the Senator John Heinz History Center in Pittsburgh, Pennsylvania.

Eventually, though, genuine cracks appeared in the Clovis-first model. In 1976, Dillehay was teaching at the Universidad Austral de Chile, Valdivia, when a student approached him with a mastodon molar found in a creek bed at the waterlogged site of Monte Verde in south-central Chile. Dillehay says he was initially uninterestedhe had come to study Andean ceramic culturesbut when the student returned with ribs that appeared to have cut marks and burn scars, Dillehay was intrigued. The bones suggested Monte Verde might be an archaeological site.

Years of subsequent excavation at Monte Verde uncoveredundeniable tracesof a human presence, preserved under peat. Researchers have confidently dated the most substantial cultural layer to about 14,500 years before the present dayat least 1,000 years older than the Clovis-first model would predict. We now know that people slept there under a long, tent-like structure made of wood and animal hides and sat around communal hearths eating potatoes and seaweed brought from trips to the coast.

Clovis-first, like any scientific theory, always had detractors. But until archaeologists confirmed the age of Monte Verde and other pre-Clovis sites in the Americas, the most vocal objections were generally outliers. In 1997, Monte Verde was inspected by a delegation of archaeologists, many of whom had questioned its purported age. They left in agreement. As Alex Barker, then chief curator of the Dallas Museum of Natural History, wrote in his report: Monte Verde is real. Its old. And its a whole new ball game.

In the last two decades, a handful of other sites, in North America especially, have gained wide acceptance as authentically pre-Clovis. Unlike the Clovis sites, most of these older sites have no distinct artifacts to connect them.

At Oregons Paisley Caves, archaeologists have dated fossilized human feces to 14,300 years ago. The Meadowcroft Rockshelter in Pennsylvania, which Adovasio began excavating in the 1970s, has a human history that may stretch back at least 16,000 years. Beneath the Clovis layers along the shores of Buttermilk Creek in Texas, researchers have found thousands of stone tool fragments dating back 15,500 years. At a site called Arroyo Seco 2 in the Pampas grasslands of Argentina, archaeologists have found 14,000-year-old butchered animal bones.

As researchers validate these finds, studies are chipping away at the story many of us read in textbooks. For one, the idea of a single pioneering population may have been a mistake. Its probably more like a dripping faucet where people are coming in at different times, from different directions, Dillehay says.

Most archaeologists would now agree that there were widely scattered, small but culturally diverse groups of people living in the Americas at least one or two millennia before the emergence of Clovis spear points. That estimate, then, placing people in the Americas roughly 15,000 years ago, is among the most conservative.

As the Clovis-first model has fallen out of favor, evenbolder chronologieshave emerged. For example, one group of scientists has made a case that they have uncovered evidence ofhumans butchering megafauna130,000 years ago at what is now called the Cerutti mastodon site in Southern Californiathough many archaeologistshave contestedthat argument. In anarticle forScience, Braje, Dillehay, and a few other colleagues wrote that the collapse of the Clovis-first paradigm has opened a Pandoras box of alternative scenarios for the peopling of the Americas, with some scholars and members of the general public quick to accept implausible claims based on limited and equivocal evidence. They cited the Cerutti mastodon site as one such example.

Genetics, meanwhile, has brought a daunting deluge of new findings, which also shed light on how and when entire lineages of people moved across continents. Genetic markers from theDNA of a childburied in what is now Alaska around 11,500 years ago, for instance, recently revealed that she shared equal DNA with all Indigenous populations in the Americas. The authors concluded she was likely descended from a population that stayed in Beringia, instead of spreading through the lower continents.

Genetics, meanwhile, has brought a daunting deluge of new findings.

The basic story some geneticists have gleaned from this and other finds is that a so-called Beringian population would have diverged from Siberian populations around 36,000 years ago. About 25,000 years ago, the Beringians became isolated, and a new genetic population emerged, one that scientists have confirmed relates to contemporary Native American people, splitting into two main lineages around 17,000 years ago.

Still, the genetic record is limitedthere are only a handful of ice age human remains that have been studiedand archaeological data are needed to both confirm that story and fill in the ancient roadmap that humans first took across these continents.

For example, theres a curious snag: The genetic data suggest one population may have spent thousands of years in Beringia, a period known as theBeringian standstill, before spreading into the Americas sometime during the Last Glacial Maximum between 27,000 and 19,000years ago.

Yet were not finding archaeological evidence of that, says genetic anthropologist Ripan Malhi of the University of Illinois, Urbana-Champaign. Without archaeological finds to back this standstill up,some researchers remain skepticalof the genetic evidence.

The route that people took is also a matter of debate. Some archaeologists remain firm that humans could have walked into North America over land, although some maintain that this route would have been prohibitively ice-covered more than 13,500 years ago.

An alternate scenario has gained traction, one that claims people first arrived on boats. According to this coastal migration theory, some 16,000 years ago the ice had retreated from the coastlines of the Pacific Northwest, such that seafaring people could take advantage of coastal resources like kelp forests to navigate all the way down the shores of California, eventually reaching sites like Monte Verde in Chile.

Proving the coastal theory is tricky. No wooden boats from that era have been found along the shore. The earliest campsites along the ancient Pacific coastline may be lost for good due to erosion and sea level rise. Yet scholars have some clues that people were living along the Pacific coast, including the footprints at Calvert Island.

Evidence of human habitation from at least 13,000 years ago on the Channel Islands in California suggests that people had the skills to build boats and reach these land masses, which were islands even then. In the last 15 years, archaeologists at Cedros Island off the coast of Baja California in Mexico have found traces of a nearly 13,000-year-old settlement. Some archaeologists, such as Loren Davis of Oregon State University, are turning to methods such as coringremoving of a long column of soilto search for hints of now-underwater prehistoric sites along the Pacific continental shelf.

Finally, many non-Native scientists are starting to appreciate that their findingshave implicationsfor Native American communities, who have had to square theirown cultural narrativesand more recent stories of displacement with scientific messages of how their distant ancestors came to the continents.

Native American scholars and activists were among the most vocal critics of the Clovis-first modelin particular the implication that Native Americans came to the continents over the Bering Land Bridgefrom the time it was first proposed. For example, in his 1995 bookRed Earth, White Lies, Vine Deloria Jr., the late Standing Rock Sioux lawyer and scholar, dismissed that migration description as scientific folklore.

Language creates reality for the world, Kim TallBear says.

To some, the scientific origin story was perceived as a means to undermine the long-term presence of Indigenous peoples on the land. After all, emphasizing how people first migrated to the Americas from elsewhere can be used to subtly imply a similarity between the ancestors of Native Americans and the European explorers millennia later. The science can be twisted to imply the land was not really that of the Indigenous peoples. Doing so downplays the real trauma and theft that occurred when European colonists took the lands of Indigenous peoples.

I think subconsciously or not so subconsciously theres this immigrant narrative, that we are all immigrants, that drives the possibilities for how scientists and how a lot of non-Indigenous people see human history on this continent, and they are really stuck in that narrative, says Kim TallBear, of the University of Alberta, who has studied the politics of tribal genetics and is a member of the Sisseton Wahpeton Oyate.

TallBear would also like to see non-Native scientists and writers think through their choice of words. Language creates reality for the world, she says. For example, referring to certain ancestral populations as first Americans or to the land as the New World can reinforce the narrative that, on some level, the Indigenous people of the Americas came from somewhere else in the recent past.

Furthermore, narratives about the first people in the Americas, TallBear notes, whether written by scientists or science journalists, tend to focus on very mechanistic and simplistic motivations for the migration, such as a search for food. She citesan articleinMacleansmagazine, for example, that presented the earliest arrivals in North America as a bedraggled group that trudged across a submerged Bering land bridge.

Intellectual reasons or reasons of curiosity, TallBear says, are ignored, as though these people had no inner life. Theres all this language that paints people on the move and migrating as if they werent these fully self-actualized human beings who also had curiosity, who laughed, who had interesting kinship dynamics, who had joy in their lives.

Fortunately, some non-Native archaeologists and geneticists arebecoming more sensitiveto the concerns of Indigenous people. My job is not to tell Native groups who they are, Davis says. They already have their own origin stories that they have been in this place forever and ever.

Scientists, Davis observes, try to fill those stories with numbers, quantifying how many years ago, for instance, people came to the Americas. From the perspective of human existenceits like, 15,000 years? I have a hard time wrapping my head around what it means to live in a place that long. That sounds qualitatively like forever, he says.

By working with Indigenous communitiesand by increasing the number of Indigenous people who are archaeologistsscientists can avoidsome of the pitfallsandnarrative blind spotsof their predecessors. These changes can also significantly further science, as the Calvert Island findings illustrate.

When scientists from the Hakai Institute and the University ofVictoria started excavations on the island, they did so alongside representatives of the Heiltsuk and the Wuikinuxv people. Those Indigenous groups have oral histories about a strip of coast that never froze and helped their ancestors survive at a time when much of the land was covered in ice. The discovery of the footprints reaffirmed this tradition. One member of the Heiltsuk NationtoldThe Washington Posthe imagined the people visiting the beach were a father, mother, and child.

Its impossible to know what they were thinking or doing that day, 13,000 years ago. Maybe the mother paused to help her child out of the boat. Maybe she laughed when her partner slipped on the damp clay. Perhaps she caught his fall. Maybe she sniffed the air that stank of low tide and squinted at the ice-covered land in the distance. Maybe she had been to this beach many times before or had heard stories about it from other members of her tribe. Or maybe, as she looked inland, she wondered if she was the first person to set foot on this shore.

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When Did Humans Reach North America? The Question Keeps Growing More Complex - The Crux - Discover Magazine

The Hinckley Institute Radio HourThis week on the program, we bring you a forum on the Abuelas de la Plaza de Mayo, a group formed in 1977 to locate and reunify with their grandchildren disappeared during the Argentinian dictatorship. This organization of women championed a matriarchal politics and began a legal, psychological and scientific movement to address the injustices and intergenerational traumas of the past. Critical to this effort was the combination of humanitarian justice, cutting edge genetic testing and international scientific exchanges that found 128 of the lost children.

This movement stands out as one in which the quest for human rights fueled scientific development and technological advancement. The genetic research conducted in Argentina would go on to advance the global study of genetic and forensic testing, popularized today by DNA testing companies like 23andMe and AncestryDNA. For their work in defense of human rights, the Abuelas de la Plaza de Mayo received the Flix Houphout-Boigny Peace Prize in Paris in September of 2011.

Giving the talk is Alexandra Minna Stern, Professor and Chair of American Culture, Professor in History, Womens Studies, Obstetrics and Gynecology in the College of Literature, Science and the Arts at the University of Michigan.

This forum was presented by the International Studies Programs Health, Medicine, and the Environment Lecture Series and made possible thanks to the support from the Center for Latin American Studies.

This forum was recorded on April 8, 2019.

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Genetics and Justice: DNA Identification Technologies in Post-Dictatorial Argentina - KCPW

SOUROUKOUDINGA: Scientists in Burkina Faso have deployed a new weapon in the fight against malaria, and waded into a thorny bioethics debate, by letting loose thousands of genetically sterilized mosquitoes.

Their experiment is the first outside the lab to release genetically altered mosquitoes in the hope of reducing their ability to spread the often deadly disease.

It works using a technique called a gene drive, which edits and then propagates a gene in a population - in this case to prevent males from producing offspring.

Investments in anti-malarial drugs, mosquito nets and insecticides have slowed malaria over the past two decades in Africa, which accounts for more than 90% of global cases.

But malaria still killed more than 400,000 people across the continent in 2017, and the World Health Organization says progress against the disease is stalling, leading researchers to push for fresh approaches.

"The conventional tools that we have at our disposal today have reached their limit," said Dr Abdoulaye Diabate, who is running the experiment for Target Malaria, a research consortium backed by the Bill & Melinda Gates Foundation.

One hot evening in July, Diabate's researchers peeled off mesh nettings from wire-rimmed containers to release about 5,000 male mosquitoes into Souroukoudinga, a village in western Burkina Faso.

The mosquitoes had been injected as embryos with an enzyme that sterilizes them.

"Our objective is not to eradicate mosquitoes," said Diabate, noting the enzyme targets only the three main species - out of more than 3,500 worldwide - that carry malaria. "The objective is . . . to reduce the density of these mosquitoes."

Target Malaria is also developing an enzyme preventing male mosquitoes from passing on X chromosomes. This results in male offspring, reducing malaria since only female mosquitoes bite - males mostly feed off plant honeydew.

Diabate said he hoped the new approaches would win approval from national regulators in the coming years for widespread use.

Using a gene drive proved effective in lab experiments at Imperial College London, where researchers last year said they had succeeded in wiping out populations of caged mosquitoes within 11 generations.

"GUINEA PIGS"

Activists in Burkina fear unintended environmental consequences.

They point to Burkina's experiment with genetically-modified cotton a few years ago, which farmers said had lowered quality and was ultimately abandoned in favor of conventional seeds.

"We are not going to allow Burkinabes to be used as guinea pigs," said Ali Tapsoba, a Burkinabe activist.

"If we intoxicate one link in the food chain, we are going to intoxicate the next link."

Those concerns echo beyond Burkina. Last November, signatories of a United Nations convention on biodiversity noted "uncertainties regarding engineered gene drives."

Critics of gene drives fear they could be used to manipulate human genetics, or develop a bio-weapon.

Researchers in Brazil have also released genetically modified mosquitoes in an attempt to control diseases like yellow fever and Zika, but it is not clear how effective that has been.

Target Malaria says it consults with communities and that research is overseen by national regulatory authorities and an independent ethics committee.

Two months after the mosquitoes were released, Souroukoudinga chief Pascal Traore told Reuters villagers were happy with the experiment's progress.

"We all believe that the project could reduce the malaria that kills our sons and daughters," he said. "This project is not just for us, but for the entire world."

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Scientists Release Sterile Mosquitoes in Burkina to Fight Malaria - News18