Showing posts with label DNA. Show all posts

Thursday, September 12, 2024

DNA suggests that the Rapa Nui arrived in the Americas two centuries before Columbus

Several moai sculptures at sunset on Easter Island.NATALIA SOLAR

DNA suggests that the Rapa Nui arrived in the Americas two centuries before Columbus

The study of 15 ancient corpses debunks the myth of the collapse of Easter Island due to overexploitation

NUÑO DOMÍNGUEZ

SEP 11, 2024

DNA extracted from 15 corpses stored in a Paris museum has yielded a monumental surprise: the Rapa Nui, inhabitants of Easter Island, the most isolated place on Earth, reached the Americas by sailing two centuries before the caravels captained by Christopher Columbus. The study provides a mind-blowing twist to the history of the tiny territory lost in the immensity of the Pacific. To the east, Easter Island is more than 3,500 kilometres (2,175 miles) from Chile, the country to which it belongs. In the opposite direction, the nearest land is the Pitcairn Islands, 1,900 kilometres (1,180 miles) away.

The first inhabitants of Easter Island were originally from Polynesia, from where they are believed to have arrived by boat around the year 1200 A.D. From that moment on, and without anyone quite knowing how, the Rapa Nui carved, transported and erected more than 900 moai, imposing human torsos that reach 10 metres in height and weigh 80 tons. DNA analysis of current members of the Rapa Nui shows that they are 90% Polynesian and 10% American. But, in 2017, the study of the remains of Rapa Nui who had lived centuries ago found no trace of American DNA, adding to the mystery.

Since 2014, Víctor Moreno-Mayar, a Mexican evolutionary anthropologist, has been studying the origin and history of the Rapa Nui. It is a difficult task, as the island community does not allow the analysis of remains of ancestors buried on the island. Moreno-Mayar’s team found a unique opportunity in boxes containing bones of supposed Rapa Nui collected by French sailors in the 19th century, which were stored in the National Museum of Natural History in Paris.

The results, published Wednesday in Nature, confirm that all of them were originally from Easter Island and lived between 1670 and 1900. Their genetic profile shows 90% Polynesian DNA and 10% American, which supports previous, smaller studies by the same team.

Whenever two people have children, their genome is split into portions and recombines, like shuffling a deck of cards. “Since we know this biological process, we can see the lengths of these blocks of American DNA and ask when they entered the Polynesian population of Rapa Nui,” Moreno-Mayar, who is currently working at the University of Copenhagen in Denmark, told this newspaper. In addition, these blocks can indicate the date when the Rapa Nui and Native Americans met and had children. “The shorter, the older the interbreeding event” and vice versa, explains the Mexican geneticist. His team’s calculations suggest that interbreeding between Polynesians and Native Americans first took place around 1300 A.D., approximately two centuries before the three vessels sent by Spain’s Catholic Monarchs and captained by Columbus reached the Caribbean coasts of the Americas in 1492, and four centuries before Europeans discovered Easter Island, in 1722.

Moais on Easter Island (Chile).GRAFISSIMO (GETTY IMAGES)

DNA does not clarify whether it was the Rapa Nui who reached the Americas or vice versa, but the former is more plausible, Moreno-Mayar’s team reasons, given the Polynesian people’s skill at navigation, often heading east and against the wind. In less than a century, the Polynesians managed to reach Easter Island and from there, the shores of South America, an astonishing achievement that leaves many questions open.

The genetic material recovered in Paris is not enough to determine how many Rapa Nui reached the Americas, or whether there were one or more arrivals. Nor, of course, what their boats were like. The data only indicate that they crossed paths with inhabitants from the west of the Andes; it is impossible to be more specific.

A navigation experiment determined that a vessel similar to the one used by the inhabitants of Easter Island to travel toward the continent would have reached the coasts near Guayaquil in Ecuador, explains Moreno-Mayar. “We have no DNA from this region, neither current nor ancient, because this molecule degrades over time, and the worst conditions for its preservation are heat and humidity,” he explains. Finding the “mirror population” of the Polynesian pioneers, descendants of these crossbreeding events, with 90% American DNA and 10% Polynesian, is a very difficult task, due in part to the fact that in South America there is much less population genetic data than in Europe or the United States.

A researcher consults the anthropological collections containing human remains at the National Museum of Natural History in Paris.JCDOMENECH

The next step in the investigation is to obtain permission from the French government to repatriate the remains of the 15 Rapa Nui analyzed, which were collected by the explorer and ethnologist Alphonse Pinart around 1870. Until the study was carried out, these bones were stored and labelled, but without much further information about their origin, explains Moreno-Mayar. Throughout their work, the team has collaborated with the Rapa Nui community, which has launched a program to recover its ancestors stored in Western museums. For now, the Parisian museum has not received any requests for these remains, according to a spokesperson for the institution, who points out that, according to French law, it should be the Chilean government that requests the recovery and the French government that decides whether it is granted.

The myth of collapse

The study also debunks the theory that the Rapa Nui culture collapsed before the arrival of Europeans due to overexploitation of the island, wars, epidemics, and even cannibalism. The first European navigators who arrived on Easter Island — first the Dutchman Jacob Roggeveen, on Easter Day 1722, hence the Western name for the island, and then the Spanish captain Felipe González de Haedo in 1770, who drew a detailed map and located the moai — could not believe how a people who did not know of the wheel or metals, and who numbered only a few thousand, could have created such colossal sculptures. The idea that Easter Island had a prosperous past, with a population of around 15,000, only to be decimated by deforestation and resource abuse around 1600, later gained traction. Despite scant archaeological evidence, the narrative was championed by influential anthropologists such as Jared Diamond, who dedicated his book Collapse to the theory, in which he spoke of “ecocide,” as if these societies were to blame for their own destruction. The Rapa Nui became a perfect metaphor for the dangerous excesses of human beings in the face of climate change.

Geneticist Víctor Moreno-Mayar, of the University of Copenhagen (Denmark), co-author of the study.

EL PAÍS

Friday, August 30, 2019

Jeffrey Epstein Hoped to Seed Human Race With His DNA

Jeffrey Epstein

Jeffrey Epstein Hoped to Seed Human Race With His DNA

Jeffrey Epstein, acusado de tráfico sexual, tenía planes para ser la semilla genética del mundo

By James B. Stewart, Matthew Goldstein and Jessica Silver-Greenberg

July 31, 2019

Over the years, Jeffrey E. Epstein surrounded himself with many prominent scientists, including several affiliated with Harvard. — CreditCreditRick Friedman/Corbis, via Getty Images

Jeffrey E. Epstein, the wealthy financier who is accused of sex trafficking, had an unusual dream: He hoped to seed the human race with his DNA by impregnating women at his vast New Mexico ranch.

The 100 best nonfiction books / No 15 / The Double Helix by James D Watson (1968)

The 100 best nonfiction books: No 15 – The Double Helix by James D Watson (1968)

An astonishingly personal and accessible account of how Cambridge scientists Watson and Francis Crick unlocked the secrets of DNA and changed the world

Robert McCrumb
Monday 9 May 2016

‘Uncompromisingly honest’: James Watson in 2007. Photograph: Edmond Terakopian/PA

im Watson was just 24 when, in collaboration with Francis Crick, he decoded the structure of DNA, “the molecule of life”. This was a 20th-century watershed, the solution to one of the great enigmas of the life sciences that would revolutionise biochemistry. In human history, without exaggeration, nothing would ever be the same again.

Watson arrived at the Cavendish Laboratory, Cambridge University, during the autumn of 1951 looking for success, fame and the love of women. He was brash, brilliant and American; a graduate zoologist from the mid-west who dreamed of winning the Nobel prize. Watson, as arrogant as he was obscure, found himself working with an equally self-possessed but somewhat overlooked older man at the Cavendish, Francis Crick, a 35-year-old would-be biophysicist who had seen service as a scientist in the second world war. In his breezy, tactless way, Watson describes his new colleague as “totally unknown [and] often not appreciated. Most people thought he talked too much.”

Soon, however, they became inseparable, habitually meeting in the Eagle, a popular Cambridge pub, a test tube’s throw from their lab. It was here that they would chew over the science issues of the day. Crick and Watson both knew that the structure of deoxyribonucleic acid (DNA) and its role in human heredity was the unconquered Everest of contemporary biochemistry. Research teams in London, Europe and California had been struggling with this mystery for at least a decade. It was the postwar science story. Watson seems to have become the catalyst for Crick’s frustrated creativity. With a surprisingly modest combined experience of advanced biochemistry, this maverick duo set out to solve the 20th century’s greatest scientific conundrum: the secret of life itself.

Watson’s personal account of their quest is both uncompromisingly honest and extraordinarily exciting, a searing portrait of two young men taking on the Anglo-American scientific establishment and winning against the odds. As some wounded participants in this story later observed, Watson’s American brashness translates into the Pepys-like candour, even naivete, of “honest Jim”, of whom the best one can say is that he is almost as hard on himself as anyone else. The Double Helix portrays a young scientist who will pick your intellectual pocket while chatting you up at your laboratory bench, before haring off to chase another Cambridge au pair girl, or “popsy”, in his American slang. Crick himself never fell out with his colleague, but he did take issue with the reckless candour of Watson’s account – a unique, compelling, and partisan picture of a scientific community riven with rivalries, hatreds, feuds and ambitions. Peter Medawar, the best science writer of the 60s, identified it immediately as “a classic”.

From 1951 to 1953, Crick and Watson embarked on a race for immortality. They faced formidable but flawed competition. Linus Pauling in California and Maurice Wilkins in London had both been studying ways to crack DNA for years, and were close to a breakthrough. But Pauling, despite massive resources, was prone to catastrophic errors. Closer to home, Wilkins (a friend of Crick’s) was at loggerheads with his brilliant x-ray crystallographer, the troubled figure of Dr Rosalind Franklin. Could Crick and Watson, two carpetbaggers from the Cavendish, acquire enough data to begin the advanced thought-experiment required to demonstrate and verify the structure of DNA?

Watson, the inevitable protagonist of The Double Helix, managed to get himself invited to a Franklin lecture in London and saw at once that her x-ray crystallography work held the key to the mystery of DNA. With hindsight, Franklin was too close to her research to grasp its significance. She was also mired in a toxic professional relationship with Wilkins, her boss. Nevertheless, Watson’s account of Franklin, the tragic figure in this story, remains exceedingly distasteful: cruel, misogynist, and flippant.

Subsequently, a full-blown biography by Brenda Maddox, subtitled The Dark Lady of DNA, has described the degree to which Franklin, who died from ovarian cancer in 1958, had perhaps unwittingly established the context of the work that Crick and Watson would develop and conclude so triumphantly. In his tight-lipped epilogue, Watson acknowledges this, conceding that Franklin “definitely [established] the essential helical parameters [of the DNA molecule] and locating the ribonucleic chain halfway out from the central axis” – a crucial admission.

He also makes a belated kind of apology to her memory, conceding how he and Crick had come to appreciate “her personal honesty and generosity, realising years too late the struggles that the intelligent woman faces to be accepted by a scientific world which often regards women as mere diversions from serious thinking.”

With a sombre expression of feeling distinctly absent from his portrait of the woman he had nicknamed “Rosy”, Watson concludes that “Rosalind’s exemplary courage and integrity were apparent to all when, knowing she was mortally ill, she did not complain but continued working on a high level until a few weeks before her death.”

Slowly, the “helical theory” took shape. Proving this still-controversial working hypothesis was the problem. “Crick and the American”, as they were known in Cambridge, were hardly helped by their bosses. “Francis and I,” writes Watson, were told that they must “give up on DNA” because there was “nothing original” in their approach. Watson describes feeling “up the creek” after this decision. By the middle of 1951, he writes, the prospect “that anyone on the British side of the Atlantic would crack DNA looked dim”. Meanwhile, far away in California, Pauling was known to be making steady progress.

But Watson had not abandoned his quest for glory. Covertly, he continued to work after hours at the Cavendish on the “helical” structure of DNA. By late 1952, Pauling had still made no new announcement. This was encouraging. “If Pauling had found a really exciting answer,” writes Watson, “the secret could not be kept for long. One of his graduate students must certainly know what his model looked like, and the rumour would have quickly reached us.” As it turned out, the news from California was far better than the Cambridge team could have expected. When, finally, Pauling did publish his latest theory, it contained a basic and fundamental flaw. Watson could not conceal his exhilaration: “Though the odds still appeared against us, Linus had not yet won his Nobel.”

In retrospect, though progress seemed agonisingly protracted and uncertain, Crick and Watson’s breakthrough occurred at warp speed, driven by “the American’s” obsessive ambition. Watson, indeed, never stopped testing new hypotheses for the structure of DNA against Crick’s wiser scepticism. Eventually, chance took a hand. It was a casual conversation Watson had with “an American crystallographer”, who had fortuitously been assigned to his lab, that provided the germ of the idea that would survive Crick’s scrutiny. On Watson’s account, it was during the late winter of 1953 that “Francis winged into the Eagle to tell everyone that we had found the secret of life”.

The “double helix”, commissioned by Watson, confronting Crick as a model in the lab, was at once supremely beautiful, wonderfully elegant and fundamentally simple. In Watson’s words: “Immediately [Crick] caught on to the complementary relation between the two chains and saw how an equivalence of adenine with thymine and guanine with cystosine was a logical consequence of the regular repeating shape of the sugar-phosphate backbone.”

Towards the end of March 1953, Crick and Watson began to write the 900-word article for Nature that would change biochemistry for ever, and add their names to the roll call of great scientists: “We wish to suggest a structure for the salt of deoxyribonucleic acid (DNA). This structure has novel features which are of considerable biological interest.” Rarely have two English sentences contained so much exhilarated understatement.

Watson’s research career, described in The Double Helix, a wide-eyed, whirlwind account of unheated university lodgings, handwritten correspondence, chance encounters in pubs or on the Cambridge train and unexpected phone calls, is a world away from the science of today. It is more than slightly personal and unequivocally “heroic”; it celebrates contingency and chance and the unscientific qualities of pride, secrecy, chauvinism and low cunning. It is raw, rash and unputdownable. In taking an impossibly complex subject and rendering an account for the ordinary reader, it has inspired a generation of accessible science writing as well as, perhaps, the popularising work of writers such as Malcolm Gladwell (Blink; Outliers) and Michael Lewis (The New New Thing).

A signature sentence

“Excitedly, I pilfered Bernal and Fankuchen’s paper from the Philosophical Library and brought it up to the lab so that Francis could inspect the TMV X-ray picture.”