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genetics

• Originally published 08/02/2013

  Archaeology: The milk revolution

  In the 1970s, archaeologist Peter Bogucki was excavating a Stone Age site in the fertile plains of central Poland when he came across an assortment of odd artefacts. The people who had lived there around 7,000 years ago were among central Europe's first farmers, and they had left behind fragments of pottery dotted with tiny holes. It looked as though the coarse red clay had been baked while pierced with pieces of straw.Looking back through the archaeological literature, Bogucki found other examples of ancient perforated pottery. “They were so unusual — people would almost always include them in publications,” says Bogucki, now at Princeton University in New Jersey. He had seen something similar at a friend's house that was used for straining cheese, so he speculated that the pottery might be connected with cheese-making. But he had no way to test his idea....

• Originally published 07/23/2013

  Adam & Albert May Rewrite the History of Man

  The DNA of Albert Perry may change the story of human origins. Perry, an African-American, approached a DNA testing company to find out more about his ancestry. The results would have come as quite a surprise (had he lived to see them), and have raised questions for geneticists around the world.It turns out that Perry carried a very different type of Y chromosome, never seen before. Every male has a Y chromosome, which is a piece of DNA inherited by sons from their fathers. But, unlike most DNA, the Y chromosome is not shuffled as it is passed down, and changes only slowly through mutation. Tracking these mutations allows scientists to create a genetic tree of fathers and sons going back through time.As a man may have several sons or none, some branches of the genetic tree die out each generation, while others become more common. Going back through time it is therefore inevitable that all modern Y chromosomes must descend from from one man at some point in the past. He has become known as “Y-chromosomal Adam”....

• Originally published 07/16/2013

  D.N.A. backs lore on pre-Columbian dogs

  BISHOPVILLE, S.C. — Inside a fenced acre on the swampy Lynches River flood plain in central South Carolina, seven of Don Anderson’s primitive dogs spring into high alert at approaching strangers. Medium-sized, they fan out amid his junkyard of improvised habitat: a few large barrels to dig under, an abandoned camper shell from a pickup, segments of black plastic water pipe and backhoed dirt mounds overgrown with waist-high ragweed....Some Carolina dogs still live in the wild, and local people have long thought they were one of the few breeds that predated the European arrival in the Americas: “Our native dog,” as Michael Ruano, another enthusiast who often works with Mr. Anderson, put it. “America’s natural dog.”

• Originally published 06/26/2013

  Genome of horse buried 700,000 years is recovered

  Researchers have reconstructed an ancient genome that is 10 times as old as any retrieved so far, and now say that DNA should be recoverable from animals that lived one million years ago. This would greatly extend biologists’ ability to understand the evolutionary past.The genome was that of a horse that lived some 700,000 years ago in what is now the Yukon Territory in Canada, and its reconstruction has already led to new insights. The researchers who sequenced it then analyzed DNA from a less ancient horse, one that lived 43,000 years ago, as well as five contemporary horse breeds and a donkey named Willy that resides in the Copenhagen zoo. They concluded that the genus that gave rise to modern horses, zebras and donkeys — Equus — arose about four million years ago, twice as far back as had been thought.Before this work, the oldest genome that had been recovered was that of a Denisovan human who lived 70,000 years ago. The new finding, if accepted, would extend by tenfold the reach of paleogenomics, the study of ancient genomes reconstructed from fossil bones. Within the last few decades this young science has become a powerful complement to paleontology, the study of fossils, as a way of reconstructing evolutionary history....

• Originally published 06/13/2013

  Is distinctive DNA marker proof of Irish genocide?

  Did you know Ireland has the highest concentration of men with the R1b DNA marker? No fewer than 84 per cent of all Irish men carry this on their Y chromosome....“The high prevalence rates have always perplexed Irish geneticists and historians,” says Alastair Moffat of IrelandsDNA. The firm’s research proposes a new hypothesis. There is already established evidence suggesting that the first farmers, (carrying the Y chromosome lineage of ‘G’, which can be found across Europe) arrived in Kerry about 4,350BC.According to IrelandsDNA, the so called ‘G-Men’ may have established farming in Ireland “but their successful culture was almost obliterated by what amounted to an invasion, even a genocide, some time around 2,500BC” (the frequency of G in Ireland is now only 1.5 per cent). “There’s a cemetery in Treille [France], where ancient DNA testing has been carried out and almost all men carry the ‘G’ marker but the women don’t,” says Moffat. They carry native/indigenous markers. This strongly suggests incoming groups of men. Because the R1b marker is still so prevalent in Ireland and is also frequently found in places like France and northern Spain we believed that around 2,500 BC, the R1b marker arrived in Ireland from the south.”...

• Originally published 05/14/2013

  Making of Europe unlocked by DNA

  A study of remains from Central Europe suggests the foundations of the modern gene pool were laid down between 4,000 and 2,000 BC - in Neolithic times.These changes were likely brought about by the rapid growth and movement of some populations.The work by an international team is published in Nature Communications.Decades of study of the DNA patterns of modern Europeans suggests two major events in prehistory significantly affected the continent's genetic landscape: its initial peopling by hunter-gatherers in Palaeolithic times (35,000 years ago) and a wave of migration by Near Eastern farmers some 6,000 years ago. (in the early Neolithic)...

• Originally published 03/29/2013

  First love child of human, Neanderthal found

  The skeletal remains of an individual living in northern Italy 40,000-30,000 years ago are believed to be that of a human/Neanderthal hybrid, according to a paper in PLoS ONE.If further analysis proves the theory correct, the remains belonged to the first known such hybrid, providing direct evidence that humans and Neanderthals interbred. Prior genetic research determined the DNA of people with European and Asian ancestry is 1 to 4 percent Neanderthal.The present study focuses on the individual’s jaw, which was unearthed at a rock-shelter called Riparo di Mezzena in the Monti Lessini region of Italy. Both Neanderthals and modern humans inhabited Europe at the time....

• Originally published 03/25/2013

  Ancient DNA challenges theory early migration

  Recent measurements of the rate at which children show DNA changes not seen in their parents -- the "mutation rate" -- have challenged views about major dates in human evolution.In particular these measurements have made geneticists think again about key dates in human evolution, like when modern non-Africans split from modern Africans. The recent measurements push back the best estimates of these dates by up to a factor of two. Now, however an international team led by researchers at the University of Tübingen and the Max Planck Institute for Evolutionary Anthropology in Leipzig, present results that point again to the more recent dates. The new study is published in Current Biology. The team, led by Johannes Krause from Tübingen University, was able to reconstruct more than ten mitochondrial genomes (mtDNAs) from modern humans from Eurasia that span 40,000 years of prehistory. The samples include some of the oldest modern human fossils from Europe such as the triple burial from Dolni Vestonice in the Czech Republic, as well as the oldest modern human skeletons found in Germany from the site of Oberkassel close to Bonn....

• Originally published 03/25/2013

  Rebecca Skloot: The Immortal Life of Henrietta Lacks, the Sequel

  Rebecca Skloot is the author of “The Immortal Life of Henrietta Lacks.”LAST week, scientists sequenced the genome of cells taken without consent from a woman named Henrietta Lacks. She was a black tobacco farmer and mother of five, and though she died in 1951, her cells, code-named HeLa, live on. They were used to help develop our most important vaccines and cancer medications, in vitro fertilization, gene mapping, cloning. Now they may finally help create laws to protect her family’s privacy — and yours.The family has been through a lot with HeLa: they didn’t learn of the cells until 20 years after Lacks’s death, when scientists began using her children in research without their knowledge. Later their medical records were released to the press and published without consent. Because I wrote a book about Henrietta Lacks and her family, my in-box exploded when news of the genome broke. People wanted to know: did scientists get the family’s permission to publish her genetic information? The answer is no.

• Originally published 03/20/2013

  Researchers publish Neanderthal genome

  Researchers in Germany have completed the first high-quality sequencing of a Neanderthal genome.The scientific data gleaned from remains of a Neanderthal toe bone found in a Siberian cave are being made freely available online. The Max Planck Institute for Evolutionary Anthropology in Leipzig said in a statement Tuesday the high quality of the genome meant its scientists were already able to determine which parts of DNA were inherited from its mother and father....

• Originally published 03/18/2013

  GM-potatoes criticized in Ireland

  Carlow, Ireland — Ewen Mullins is the face of modern Ireland: Young, cosmopolitan, highly educated, he is a plant scientist whose work on a genetically modified potato inherently looks to the future. But Mullins also must think back to one of Ireland’s darkest chapters, the Great Famine of the 1840s.“It’s always there,” he said. “It’s not something we forget or something we should be allowed to forget.”From his laboratory and greenhouse in a research farm outside Carlow, 42-year-old Mullins deals daily with a disease that not only afflicts his native land but haunts it: the potato blight, a pernicious rot caused by a fungus that still thrives in Ireland’s wet, cold climate....

• Originally published 02/04/2013

  Darwin’s birds get new look

  In 1855, Charles Darwin took up a new hobby. He started raising pigeons....Pigeon breeding, Darwin argued, was an analogy for what happened in the wild. Nature played the part of the fancier, selecting which individuals would be able to reproduce. Natural selection might work more slowly than human breeders, but it had far more time to produce the diversity of life around us.Yet to later generations of biologists, pigeons were of little more interest than they are to, say, New Yorkers. Attention shifted to other species, like fruit flies and E. coli.Now Michael D. Shapiro, a biologist at the University of Utah, is returning pigeons to the spotlight....

• Originally published 01/31/2013

  Aztec conquest altered Mexican genetics

  AUSTIN, Texas — For centuries, the fate of the original Otomí inhabitants of Xaltocan, the capital of a pre-Aztec Mexican city-state, has remained unknown. Researchers have long wondered whether they assimilated with the Aztecs or abandoned the town altogether.According to new anthropological research from The University of Texas at Austin, Wichita State University and Washington State University, the answers may lie in DNA. Following this line of evidence, the researchers theorize that some original Otomies, possibly elite rulers, may have fled the town. Their exodus may have led to the reorganization of the original residents within Xaltocan, or to the influx of new residents, who may have intermarried with the Otomí population.Using ancient DNA (aDNA) sampling, Jaime Mata-Míguez, an anthropology graduate student and lead author of the study, tracked the biological comings and goings of the Otomí people following the incorporation of Xaltocan into the Aztec empire. The study, published in American Journal of Physical Anthropology, is the first to provide genetic evidence for the anthropological cold case....

• Originally published 01/25/2013

  Clues to prehistoric human exploration found in sweet potato genome

  Europeans raced across oceans and continents during the Age of Exploration in search of territory and riches. But when they reached the South Pacific, they found they had been beaten there by a more humble traveler: the sweet potato. Now, a new study suggests that the plant's genetics may be the key to unraveling another great age of exploration, one that predated European expansion by several hundred years and remains an anthropological enigma.Humans domesticated the sweet potato in the Peruvian highlands about 8000 years ago, and previous generations of scholars believed that Spanish and Portuguese explorers introduced the crop to Southeast Asia and the Pacific beginning in the 16th century. But in recent years, archaeologists and linguists have accumulated evidence supporting another hypothesis: Premodern Polynesian sailors navigated their sophisticated ships all the way to the west coast of South America and brought the sweet potato back home with them. The oldest carbonized sample of the crop found by archaeologists in the Pacific dates to about 1000 C.E.—nearly 500 years before Columbus's first voyage. What's more, the word for "sweet potato" in many Polynesian languages closely resembles the Quechua word for the plant....