Charles Darwin may have been right in worrying that the ill health that plagued his family were a result of inbreeding. Darwin didn’t only marry his first cousin, Emma Wedgwood–in fact, the Darwins and the Wedgwoods made a habit of intermarrying (Darwin’s maternal grandparents were also third cousins). Now a new study, which crunched the numbers on first-cousin marriages over four generations of the two dynasties, suggests that his children had an elevated risk of health problems.
The degree of inbreeding among Darwin’s children, while not excessive, was enough to increase the risk of recessive diseases — ones that occur if a harmful version of a gene is inherited from both parents. Three of his 10 children died before age 10 — 2 of bacterial diseases. Childhood mortality from bacterial infections is associated with inbreeding. So, too, is infertility, and three of Darwin’s children who had long marriages left no children [The New York Times].
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Last week, Lee Berger unveiled for the world the stunningly intact fossil finds (that his 9-year-old son actually made while with his dad in South Africa) from what he is calling a new hominid species, Australopithecus sediba. Yesterday, he announced another surprise: Berger says that brain scans just finished in France show that insects that might have feasted on the person after death, and even possibly a piece of the hominid’s brain, may be preserved inside the recovered skull.
Experts at the European Synchrotron Radiation Facility (ESRF) in France have been analyzing the find. The ESRF uses a technique known as micro-tomography to assemble its images. This involves taking a series of a high-contrast, high-resolution X-ray radiographs of the target fossil in rotation to build up a 3D representation [BBC News]. The scientists were trying to study the teeth; the skull comes from a young boy, Berger says, and they hoped tooth analysis could help them pin down his exact age at death. But the 3-D representation revealed these other unexpected finds, including a low-density cavity in the skull that could—could—represent a brain remnant.
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When I was 9 years old I desperately wanted to be a paleontologist, but sadly, daydreams of unearthing dinosaurs led to no significant fossil finds in my backyard. So I must confess unending respect for Matthew Berger, who, at age 9, quite by accident made a stunning scientific find. In the journal Science this week, Matthew’s father paleoanthropologist Lee Berger describes the fossils of a brand-new hominid species that they turned up in South Africa: Australopithecus sediba, which dates back to between 1.78 and 1.95 million years and could offer new hints about that era of human evolution.
Matthew was chasing his dog near a site where his father had long hunted for fossils when he tripped over the find. The bones belong to a pre-teenage boy and a woman estimated to be in her late 20s or early 30s; the individuals died at about the same time, and before their remains had fully decomposed, they were entombed in an avalanche of sediment and nearly perfectly preserved deep in the Malapa cave north of Johannesburg, South Africa [TIME]. As a result, Lee Berger says, the bones are in an astonishing state for their nearly 2-million-year age.
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Former Roman Catholic priest and respected evolutionary biologist Francisco Ayala has won this year’s Templeton Prize. The $1.53 million award honors a living person “who has made an exceptional contribution to affirming life’s spiritual dimension, whether through insight, discovery, or practical works.” The John Templeton Foundation cited Ayala’s dogged work through the years advocating the peaceful co-existence of science and religion in its decision. The somewhat controversial prize is often given to scientists who find common ground between religion and science, but previous winners have also included more traditional spiritual leaders like Mother Teresa and televangelist Billy Graham.
Ayala is the former president of the American Association for the Advancement of Science and is respected for his research into the evolutionary history of the parasite scientists have associated with malaria, with an eye toward developing a cure for the disease. He also pioneered the use of an organism’s genetic material as molecular clocks that help track and time its origins [The Christian Science Monitor]. But he is known best, perhaps, for being an expert witness in the 1981 federal court trial that led to the overturning of an Arkansas law mandating the teaching creationism with evolution in science class. In 2001, he was awarded the National Medal of Science.
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In 2008, archeologists working at the Denisova Cave in Siberia’s Altai Mountains discovered a tiny piece of a finger bone, believed to be a pinky, buried with ornaments in the cave. Scientists extracted the mitochondrial DNA (genetic material from the mother’s side) from the ancient bone and checked to see if its genetic code matched with the other two known forms of early hominids–Neanderthals and the ancestors of modern humans. What they found was a real surprise. The team, led by geneticist Svaante Paabo of the Max Planck Institute, discovered that the mtDNA from the finger bone matched neither–suggesting there might have been an entirely different hominid species that roamed the planet about 50,000 years ago.
Looking back at the region and the cave, where scientists earlier discovered artifacts from humans and Neanderthals, Paabo thinks that it is possible that all the three species (modern humans, Neanderthals and the mystery hominids) could have possibly met and interacted with each other. The findings, which were published in journal Nature, present an unexpected twist in the story of human evolution and migration.
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For years, scientists have debated where humanity’s sense of fairness came from. Some proposed it was a glitch in the brain’s wiring that causes people to be kind and fair to strangers, while others said it was a remnant of Stone Age thinking--that deep in our brains we see everyone we meet as part of our tiny family, and can’t imagine encountering someone who won’t ever be seen again [Wired]. But now, in a new study published in Science, scientists studying groups of people from different societies have suggested that our sense of fairness may depend on the type of society we live in.
The researchers found evidence that the more complex the society, the more developed those people’s sense of fairness. You can’t get the effects we’re seeing from genes,” said Joe Henrich, a University of British Columbia evolutionary psychologist and co-author of the study.” These are things you learn as a consequence of growing up in a particular place” [Wired].
For this study, scientists observed 2,100 people from different societies–from African herders, Colombian fishermen, and Missouri wage workers. The groups varied in size, and researchers also evaluated the people’s involvement in organized social activities like markets and religion–a common marker, scientists say, of the presence of a moral code that extends beyond kin. They then administered a series of games to study how group members viewed selfish behavior and how willing they were to punish it.
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A cache of ostrich eggshell fragments discovered by archaeologists in South Africa could be instrumental in understanding how humans approached art and symbolism as early as the Stone Age. The eggshells, engraved with geometric designs, may indicate the existence of a symbolic communication system around 60,000 years ago among African hunter-gatherers [Discovery News].
At a site known as the Diepkloof Rock Shelter, a team led by archaeologist Pierre-Jean Texier discovered fragments of 25 ostrich eggs that date back 55,000 to 65,000 years. In an online paper published in the Proceedings of the National Academy of Sciences, the archeologists revealed that the eggshell fragments were etched with several kinds of motifs, including parallel lines with cross-hatches and repetitive non-parallel lines [ScienceNow]. The scientists are confident that the markings are almost certainly a form of messaging — of graphic communication [BBC].
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With the genetics age coming into its own, the number of people who have had their genome sequenced could soon explode. But the genetic sequencing done so far has mostly left out African people, genetics researcher Stephan Schuster says. So he led a team that sequenced the genome of five people native to southern Africa—including famed anti-apartheid activist Archbishop Desmond Tutu—and found incredible genetic diversity compared to people in other parts of the world. The findings are in the journal Nature.
The genome of the archbishop, who is 79, was particularly important for the study because he is a Bantu descended from the Tswana and Nguni people, who account for around 80% of southern Africans [The Guardian]. The other four subjects were bushmen: One, named !Gubi, had his entire genome sequenced, while the other three were partially sequenced. (The exclamation point indicates a clicking sound in that Bushman language.) !Gubi is the first person from an African minority population to be fully sequenced, and comparing him to the other three men from the region shows as much genetic separation as you’d expect to find between European and Asian peoples. Says Schuster: “This is despite the fact that they sometimes live within walking distance of one another” [Nature News].
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Once again, to the bane of myth-makers and fans of historical intrigue, the simplest explanation may be the best: Scientists analyzing the DNA of the world-famous mummy of Tutankhamen say that he wasn’t done in by murder nor any of the exotic diseases put forth as explanations for his death at the age of 19. Rather, they say in the Journal of the American Medical Association, it was likely complications of malaria that killed King Tut, who was already frail thanks to royal inbreeding.
The team led by Egypt’s top archaeologist, Zahi Hawass, spent years taking CT scans and conducting genetic tests on mummies from the royal tombs. They say they confirmed that Tut was the son of Akhenaten, which is what scholars have long believed, but it hints at something else: It also identifies some of his grandparents and great-grandparents for the first time and suggests that his mother was Akhenaten’s sister [The Times]. A brother-sister pair wasn’t unusual during this period in ancient Egypt, medical historian Howard Markel says. Pharaohs were thought of as deities, so it makes sense that the only prospective mates who’d pass muster would be other deities [AP].
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Have you seen this man? Probably not: He lived 4,000 years ago.
The image to the left is not a wanted poster, but rather an artist’s impression of Inuk, the name given to him by the scientists who sequenced his genome. It’s the first time the genetic code of an ancient human has been deciphered this completely, and the researchers published their results this week in Nature.
Inuk died on an island off Greenland called Qeqertasussuk. Researchers don’t know the cause of death, but they do know he left bits of hair and bone that the permafrost preserved. Scientists found the thick clumps of hair—which could be the remnants of a 4,000-year-old haircut—in the 1980s, and stored them in the National Museum of Denmark. Today’s DNA sequencing technology allowed them to look back in time at what he may have been like. Inuk’s genes reveal he was a fairly young man, robustly built to exist in a frigid climate, with A-positive blood, dark skin, brown eyes, and thick, black hair on a scalp genetically susceptible to baldness [San Francisco Chronicle].
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Last year DISCOVER asked the question, “Did We Mate With Neanderthals, or Did We Murder Them?” Now, Zach Zorich at Archaeology magazine is asking another big question about our hominid siblings: Should we bring them back?
Thanks to a slew of recent advances, the possibility is getting closer. 80beats reported a year ago that researchers had published the rough draft of the Neanderthal genome. However, that’s likely to contain many errors because it’s so difficult to reconstruct ancient DNA. Within hours of death, cells begin to break down in a process called apoptosis. The dying cells release enzymes that chop up DNA into tiny pieces. In a human cell, this means that the entire three-billion-base-pair genome is reduced to fragments about 50 base-pairs long [Archaeology].
Even if scientists succeed in figuring out the entire Neanderthal genome, they’d be faced with another problem before they could even consider the possibility of cloning one of these ancient hominids: We don’t have any living Neanderthal cells to work with. Thus, researchers will have to figure out how to put DNA into chromosomes, and how to get those chromosomes into the nucleus of a cell. What about altering the DNA inside a living human cell, and tweaking our genetic code to match the Neanderthal’s? This kind of genetic engineering can already be done, but very few changes can be made at one time. To clone a Neanderthal, thousands or possibly millions of changes would have to be made to a human cell’s DNA [Archaeology].
Even if scientists manage to put Neanderthal DNA in a cell nucleus, their problems aren’t over. The next step in creating a baby clone is to move the cell nucleus into the egg of a related species in a technique called nuclear transfer, and then implanting the altered egg in a female who can bear it to term. But in this process, which has been extensively tested on animals, cells often get sick or die, causing fetuses to die in the womb or clones to die young. That’s why the vast majority of scientists oppose using this method on people. Even if nuclear transfer cloning could be perfected in humans or Neanderthals, it would likely require a horrifying period of trial and error [Archaeology].
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Brazil’s controversial plan to build the third-largest dam in the world right in Amazon rainforest got the go-ahead from the environmental ministry this week. The ministers approved the permits for the dam project, and now companies can begin to bid on the building rights. But whoever wins will have to pay out at least some money to protect the local environment.
The 11,000-megawatt Belo Monte dam is part of Brazil’s largest concerted development plan for the Amazon since the country’s military government cut highways through the rainforest to settle the vast region during its two-decade reign starting in 1964 [Reuters]. Nearly all huge dam projects raise environmental concerns because they flood vast areas and can change ecosystems so drastically. But the Belo Monte, to be built on the Xingu River, has the additional trouble of being in one of the most important habitats in world and near to populations of indigenous peoples. The Xingu is a tributary of the Amazon River.
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Don’t count out the Y chromosome just yet. Far from being in a state of decay, as some studies have suggested, a new study in Nature says the male chromosome in humans is actually evolving at a furious pace.
Study leader David Page of MIT sequenced the human Y chromosome back in 2003, and in the new study his team compares it to the male chromosome of chimpanzees. The scientists expected the two sequences to look very similar. However, while human and chimp DNA generally differ by less than 2 per cent, more than 30 per cent of the Y chromosome differed between the two species [The Times].
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Forget the myths about massive numbers of slaves or Jews building the great pyramids, Egypt‘s chief archaeologist argues this week. He says Egyptian researchers have found the tombs of more pyramid builders, and in those tombs more evidence that free men erected these monumental tributes to the ancient pharaohs.
Zahi Hawass this week unveiled new research on 4,000-year-old tombs found near the pyramids—tombs he says belonged to pyramid builders. Graves of the pyramid builders were first discovered in the area in 1990 when a tourist on horseback stumbled over a wall that later proved to be a tomb [Canadian Press]. These new ones stretch beyond those previously-discovered tombs, and contain a dozen skeletons.
What matters for the historical interpretation, Hawass stressed, is location, location, location. “These tombs were built beside the king’s pyramid, which indicates that these people were not by any means slaves,” said Mr Hawass. “If they were slaves, they would not have been able to build their tombs beside their king’s” [The Times]. In addition, Hawass says that the walls of the tombs (which the builders probably built for themselves) bear graffiti like “friends of Khufu (a pharaoh).”
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The jewelry in Spain speaks mainly to the brains (of Neanderthals). So says a team of archaeologists this week in the Proceedings of the National Academy of Sciences. Researchers led by João Zilhão have turned up artifacts they believe to be jewelry dating back 50,000 years—a time only Neanderthals and not early humans occupied Europe—suggesting to them that those Neanderthals were capable of the abstract thinking necessary to make symbolic art.
Zilhão’s team found shells and bones that showed evidence of craftsmanship, the scientists say. First, some of the shells were perforated and could have been strung and worn as a necklace. It’s not out of the question that those holes could be natural, but the team says the finds also appear to have been painted. If the researchers’ analysis is correct, the Neanderthals could have mixed up reddish goethite and hematite, yellow siderite and natrojarosite, black charcoal and sparkly pyrite to create a spectrum of paints [MSNBC].
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