Mystery of Native Americans’ arrival

first_imgThe Americas’ first human settlers arrived in a complex series of migrations, pushing over the ancient land bridge from Asia at least three times but moving in both directions, with at least one group scrapping it all and bringing themselves and their genetic signature back home to Asia.Research conducted by an international team led by scientists from Harvard University and University College London illuminates the roots of today’s Native Americans through genetic analysis and by comparison with native groups in Siberia.The results, published in the July 11 issue of the journal Nature, examined genetic data from 52 Native American groups and 17 Siberian groups, and helped settle a debate among anthropologists over whether the Americas were settled just once or several times.The results not only show that multiple waves of settlers arrived on the continents’ shores from Asia, but that some groups reversed direction. In addition to those that headed home to Asia, another that made it to South America migrated back north to Central America.The work made no findings about the timing of settlement, but prior research indicates that the first humans reached North America some 15,000 years ago when the massive glaciers of the last ice age locked up enough water to lower sea levels and expose a 1,000-mile-wide land bridge between Siberia and Alaska.The current research, led by David Reich, professor of genetics at Harvard Medical School, and by Andres Ruiz-Linares of University College London, shows that the majority of the genetic signature of today’s Native Americans comes from an initial migration during which people, termed “First Americans” by the researchers, pushed south along the Pacific Coast from Alaska to the tip of South America.The second migration was smaller geographically but had a large impact on the native people of the far north. Today’s Aleut-Inuit populations owe about half of their genetic background to this second migration.The third migration contributed about 10 percent of the genetic background of Canada’s Chipewyan people, concentrated today around Hudson Bay.“The Americas are, of course, an important region of the world,” said Reich. “The native peoples of America have a fascinating and contentious history. It’s very important to understand how people first got here and how people dispersed within the Americas.”The return of some Native Americans to Asia was revealed only as researchers struggled to understand their data, Reich said. Early results clearly indicated the migration of First Americans along the coast to South America, but the results for North America were more complex. As researchers struggled to decipher the data, they traced their confusion to a false assumption: that the DNA signature from Asia was purely ancestral and contained no later recombination with Native American genes.Once they took that possibility into consideration, it became clear there had been at least three migrations from Asia to America and at least one back to Asia, contributing Native American genes to the Naukan and Chukchi people of northeastern Siberia.The four-year study involved 64 researchers from institutions around the world. Key to the work, Reich said, was access to genetic information on native peoples collected over many years by senior author Ruiz-Linares.In conducting the research, scientists studied more than 300,000 genetic changes called single-nucleotide polymorphisms, which are isolated changes in the molecules that make up DNA’s long, twisting structure.The work was further complicated by multiple genetic changes in native peoples since 1492, when the continents’ conquest and settlement by Europeans began, followed by the arrival of African slaves and of later immigrants. Using techniques refined in earlier research, Reich said researchers were able to isolate and study portions of the genome known to be of Native American origin.Though the research has settled one important question, the work is far from done, Reich said. Further investigation, particularly of native people of northern North America where sampling was thin, can further enrich the picture of the hemisphere’s original inhabitants.“No picture of human history is complete. The harder you look at it, the more there is to find,” Reich said. “What we’ve shown is that there were at least three streams of gene flow from Asia, but there could easily — perhaps are likely to have been — more. There’s just some that we can’t detect.”last_img read more

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Survivors of Beirut’s explosion endure psychological scars

first_imgBEIRUT (AP) — Beirut’s massive explosion in August killed more than 200 people and injured thousands, but it wreaked perhaps even wider damage to mental health among Lebanese. Many of those who lived through it struggle with depression or symptoms of post-traumatic stress disorder. Thunderstorms or the frequent sound of Israeli warplane flyovers cause terror among some, forcing them to relive the blast. The explosion was unique even for conflict-scarred Lebanon, with tens of thousands of people experiencing the same traumatic event. It comes on top of multiple other crises causing stress, including an economic meltdown and the pandemic. Demand for therapists has ballooned even as many are unable to get treatment.last_img read more

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Trojans dominate Gauchos in home opener

first_imgIt was a top-five matchup in the Uytengsu Aquatics Center on Saturday, when No. 4 USC took on No. 5 UC Santa Barbara. In the Trojans’ (12-2, 2-0 MPSF) first game at home this season after playing on the road for four straight weeks, the team took out the Gauchos by a final score of 14-5.Newbie · Freshman goalkeeper McQuin Baron continued his domination against the Gauchos, recording 12 saves. Baron now has 102 in his career. – Mariya Dondonyan | Daily TrojanUCSB opened the scoring with a 6-on-5 goal, but USC responded quickly with two goals of its own to take a 2-1 lead. The Trojans went on a 5-0 scoring run soon after, and their lead was 9-2 at the half. In the third, the Trojans and Gauchos split two goals apiece, making the score 11-4 at the end of the period. USC was in complete control in the fourth frame, scoring three goals to the Gauchos’ one.The last time the Trojans played UCSB, the match was much more contested and resulted in a 12-7 Trojan victory in the Kap7 NorCal Classic earlier this season.Head coach Jovan Vavic believes his team’s improved performance against the Gauchos is due to  differences in preparing for a tournament versus preparing for a single game.“I think we are a little bit more prepared today because when we played them last time, we didn’t know who we were going to play because it was dependent on what they did in the game before, so we really were not preparing for them,” Vavic said. “We were getting ready for any opponent.”In the first half of Saturday’s game alone, nine different Trojans scored each of the team’s goals. Vavic believes that sharing the wealth is key to his team’s success.“That is the strength of our team, and every coach likes to see more people score,” Vavic said. “Everybody knows [senior driver] Kostas [Genidounias] is our main guy, and everyone is going to try to shut him down, so having so many different people score was big. We hope we continue to do that.”It was a significant win for USC, but also for several of the Trojan players, including freshman goalie McQuin Baron. The last time the two teams played, Baron had a career-high 15 saves. On Saturday he picked up 12 more.Baron believes this success is rooted in his focus and discipline.“Every week I try and prepare as best I can, watch video on each shooter on their offense just what they’re doing, learn how they’re trying to play,” Baron said.Vavic is very happy with this rookie’s progress.“He did an excellent job today,” Vavic said. “He was very focused. He did a good job not only blocking the shots but making some good passes in the counterattack. Baron is a special talent. He’s the backbone of our defense. Very pleased with his performance today.”In addition to Baron’s big day, one of the game’s biggest moments came when Genidounias scored the first of his three goals and became USC’s second all-time leading scorer, breaking his tie with former Trojan Juraj Zatovic. Genidounias was humble about the achievement, however, saying that winning was his only priority.“Before the game it was on my mind, but it wasn’t as important as getting the win,” Genidounias said. “It was a team effort. I don’t score the goals by myself. Someone has to give me the pass, so it’s a good team effort and I scored a few goals, and I’m up there at number two. It’s good with me but not as important as winning.”The game was even more special because it was officially the first ever in the newly completed USC facility. Vavic was very pleased with the new arena.“It’s great,” Vavic said. “I think it’s a very special place now because it’s so beautiful, so perfect for water polo. We have been looking forward to playing here for a while now so it was exciting. You could tell our guys are excited the way they started the game.”USC will play in the SoCal Tournament hosted by UCLA next week. After Saturday’s win, the Trojans are confident they will perform better than they did in their last tournament, the NorCal Classic, which resulted in a fourth place finish.Genidounias believes he and his team can keep up the success they have had in the past two weeks.“We hope to go back to that tournament and have a better showing than in the NorCal tournament,” Genidounias said. “I think that now with all of our new players having a few extra games and learning the system, that’s a key for us for our new players to feel more comfortable in the system with each other. I think we’re going to be a little bit of a tougher team than we were in the NorCal Tournament.”Baron also believes that even two weeks more experience for him and his young team is invaluable.“I think we’re definitely more prepared now,” Baron said. “We had more time together. We’re a very young team, so we’re still learning how to play with each other and work as a unit. But we’re definitely coming together better day by day.”last_img read more

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Iowa to launch statewide rape kit tracking system

first_imgDES MOINES — After a recent survey found thousands of sexual assault evidence kits were left untested in Iowa, the state is launching a plan to keep close track of such rape kits in the future.Lynn Hicks, communications director for the Iowa Attorney General’s Office, says a sample-tracking software company is being hired to roll out its Track-Kit system to all regions of the state by mid-2020.Hicks says, “Basically, it will follow the rape kits from the time a kit is at the medical facility or hospital and used in an exam, and then all the way through the final disposition of the case.”According to Hicks, the system will connect more than 1,200 users at Iowa medical facilities, law enforcement agencies, crime laboratories, and county attorney’s offices.“Most important, it will allow that sexual assault survivor to be able to get information on the status and location of the kit,” Hicks says, “so they would be able to follow it throughout the process.”A survey in 2017 by the Iowa Attorney General’s Crime Victim Assistance Division found more than 4,200 untested rape kits in police departments and sheriff’s offices across Iowa. Efforts are being made, Hicks says, to tackle that backlog, but the new tracking system is also crucial.“We think this is going to be a big step forward,” Hicks says. “This software will increase the accountability and transparency throughout the process and ultimately will empower survivors of sexual assault.”Of the 4,200 untested rape kits found statewide, more than 1,600 have been sent to private labs for testing. From those, Hicks says 235 DNA profiles have been entered into CODIS, the FBI’s Combined DNA Index System. Of those, 127 were hits, or matches to DNA in the database, enabling the information to be forwarded on to prosecutors.last_img read more

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