A clue to biodiversity?

first_img Research on butterflies reveals genetic sharing Vivid details Scientists have found that some passion vine butterflies (Heliconius) share similar color patterns that help ward off predators because they actually share parts of their DNA as a result of hybridization somewhere in their ancestry.But a new study in Science provides evidence that the process of sharing DNA may be far more common than ever thought, offering a potential clue to how biodiversity took place.An analysis of 20 butterfly genomes found evidence that many butterfly species — including distantly related ones — show a surprisingly high amount of gene flow between them, said James Mallet, professor of organismic and evolutionary biology in residence and associate of population genetics in the Museum of Comparative Zoology, the senior author of the study.“DNA sharing had been shown in closely related species, but we wanted to probe deeper into the phylogenetic tree,” Mallet said. “What we found is really astonishing: introgression even among species that are distantly related. ‘Species’ are simply not what we thought they were, and now we have the data to show it. The evolutionary tree of butterflies is a complete morass of interconnectedness.”For Mallet and colleagues, understanding how butterflies pass genes back and forth — a process known as introgression — began with the creation of 20 new “genome assemblies” of various species in the Heliconius family.Those assemblies, explained Nate Edelman, lead author on the paper and a graduate student in the Mallet lab, essentially function as genomic maps, and are constructed by sequencing short fragments of DNA and then assembling them in the proper order.Once created, those maps can also serve as important resources for future researchers, allowing them to map genes back to the genome.“The cool thing about making genome assemblies instead of simple genome “resequencing” is that it’s not just the DNA bases that change — the entire structure of genomes can change through evolutionary time,” Edelman said. “And using the assemblies, we can detect those changes.”When they began analyzing the assemblies, Mallet said, the team not only found evidence that some genes were capable of moving between species, but that others were far more resistant to the process.And one of the key factors determining whether genes could or could not move is a basic biological process called recombination.,Part of the process of creating sperm and egg cells, recombination occurs when the two copies of every gene a creature inherits — one from its mother, another from its father — are jumbled together, resulting in a unique mix of both.“It might seem that useful genes are more likely to be transferred between species,” said Michael Miyagi, the other main graduate student author. “That’s true, but there are also more mundane structural issues with the genome that mean some regions are more likely to have genes go back and forth.”And whether those genes flow back and forth, Edelman said, often depends on how much those different regions recombine.“In low-recombination regions, we tend to see more resistance to gene flow than in high-recombination regions,” he said. “What we think happens is that in very-high-recombination regions, the genes that are resistant or incompatible become dissociated from the genes that can flow across the species boundary.”And in a lucky break, Miyagi said, the team identified a key gene that acts to switch color patterns as one of those that moved between species. “In nature, it’s very unlikely that any individual will mate with a member of another species. But over evolutionary time, it does happen.” — James Mallet Related “Heliconius are famous for their color patterns … and we found that in one particular region of the genome there are about 500,000 base pairs that have been inverted relative to the ancestral sequence,” he said. “And smack in the middle of that inversion is that gene that we know controls color pattern. When you have an inversion like that it means you’re keeping all the things within it together, so they can’t recombine.”In another case, Edelman said, the team discovered an even larger inversion on a different chromosome that remains a complete mystery.The team was able to show that one of those inverted sequences was transferred, Mallet and Edelman said, thanks to a new analysis method developed by Miyagi.Ultimately, Mallet, Edelman, and Miyagi said, the study shows that hybridization — however unlikely it may be — is one way for species to derive their genomes and may be a key process in the creation of the diversity of life we see today.“In nature, it’s very unlikely that any individual will mate with a member of another species,” Mallet said. “But over evolutionary time, it does happen.“It probably only happens in the youngest groups of species — species that are rapidly evolving,” he continued. “Most of the diversity of life is probably created in these rapid radiations. They are involved in things like the origin of mammals. During these radiations, this could be an important means of shuffling variation and recombining adaptations from different lineages.”This research was supported with funding from a SPARC grant from the Broad Institute of Harvard and MIT and startup and studentship funds from Harvard University. last_img read more

I Will Never Feel Great Again, Says Tiger Woods

first_imgWoods’ first return to competitive action after a 15-month lay-off came in December at the Hero World Challenge – an 18-man tournament in the Bahamas – and he finished 15th at the PGA Tour event.He hopes to compete in the Masters at Augusta from 6-9 April.“There have been plenty of times when I thought I would never play the game again at the elite level,” added Woods, who has won 79 titles on the PGA Tour.“It was tough, it was more than brutal. There were times I needed help just to get out of bed.“I feel good, not great. I don’t think I will ever feel great because it’s three back surgeries, four knee operations.“I’m always going to be a little bit sore. As long as I can function, I’m fine with that.”Woods has not won a tournament anywhere since 2013, while his title drought in major championships dates back to 2008.“There is a changing of the guard,” he said. “My generation is getting older but if I’m teeing up then the goal is to win.Share this:FacebookRedditTwitterPrintPinterestEmailWhatsAppSkypeLinkedInTumblrPocketTelegram Fourteen-time major winner Tiger Woods has said that he will “never feel great” again because of the number of injuries suffered during his career.Woods, 41, pulled out of the Dubai Desert Classic before the second round this month because of a back spasm.He only returned to action in December after two back operations.“There were a lot of times I didn’t think I was going to make it back. It was tough, it was more than brutal,” Woods told Dubai magazine Vision.last_img read more

Viterbi collaborates with Hollywood

first_imgThe Viterbi School of Engineering is collaborating with the National Academy of Engineering, an elected group of the world’s most accomplished engineers, for a worldwide crowdsourcing competition to cast a female engineer for the new MacGyver TV show. The show hopes to inspire more women to pursue engineering.MacGyver, created by Lee Zlotoff, was launched 30 years ago and follows the adventures of a fictional government agent Angus MacGyver, who resourcefully uses his engineering skills to solve problems in each episode.“I was intrigued and excited when the USC Viterbi School of Engineering first suggested the idea of a script competition to help create a new, female engineer-type character for TV,” Zlotoff wrote in an email to the Daily Trojan. “And I was pleased that we could use the name and example of MacGyver to help make this competition a reality.”Adam Smith, the senior manager of communications and marketing at Viterbi and the primary coordinator of this project, said that Hollywood and engineering should be working together to motivate more students to pursue engineering.“This idea of marriage between engineering and Hollywood has been around for a long time,” Smith said. “Andrew Viterbi wrote about how we can use this to elevate engineering to a higher status.”Dan Mote, the president of the National Academy of Engineering, agrees with Smith on the alliance of engineering and Hollywood, emphasizing the importance of exciting women about the prospect of a profession in engineering.“‘The Next MacGyver’ search competition is an opportunity that hits the bull’s eye twice for engineering,” wrote Mote in an email to the Daily Trojan. “First, the program lead is a female engineer who will inspire young women to think about engineering as a career. Second, it provides the public a program on engineering and what engineers do.”Smith said he and his team came up with this idea of reaching out to the National Academy of Engineering for a global competition in 2013, and they wanted to make female engineers the focus. In fall 2014, they received a grant from the United Engineering Foundation.Smith believes that they will be able to inspire more women to pursue engineering through this project.“In terms of changing a national culture, it requires a big catalyst, and we believe that TV and popular culture have a big play in that,” Smith said.He explained that television is filled with problems and conflicts, and engineers are great at finding solutions to solve these.Viterbi student organizations have made efforts to encourage local young women to pursue engineering majors.“In terms of current efforts, this Thursday, the local chapter of Society of Women Engineers and Women in Engineering are hosting an [all-day] workshop for young women in the community,” Smith said.As part of Engineers’ Week, “Introduce a Girl to Engineering Day,” co-hosted by the Association for Computing Machinery, hopes to inspire the next generation of female engineers by introducing the girls to circuits using Circuit Scribe, a rollerball pen that writes with conductive silver ink, while also teaching them about the process of problem-solving and invention.Smith said Dean Yannis C. Yortsos considers the diversity at Viterbi a great accomplishment, citing that of the entering class 37 percent are women, which is double the national average. Additionally, 25 percent of the computer science majors are women.“I think it’s great to see more female leaders in the engineering community and it shows, perhaps maybe more to younger people who are thinking about going into engineering, that women can be engineers as well and it’s just not a male dominated field,” said Morelle Arian, a senior majoring in electrical engineering.“While there has been some debate about whether our country needs more engineers, one thing is certain: engineering needs more women,” Randy Atkins, the senior media relations officer at the National Academy of Engineering, wrote in an email statement to the Daily Trojan. “While more than half the talent pool seems generally turned off by the thought of becoming an engineer, it’s likely most kids don’t even know what an engineer does. Considering that engineers will be key to tackling the [grand challenges] of the 21st century, this is very troubling.”Daisy Leon-Rivera, a junior majoring in biomedical engineering, said she watched [the children’s show] Cyber Chase growing up because she enjoyed the problem-solving techniques and math the characters used.“I think this is a great opportunity to inspire the next generation of … engineers of the future, and I hope it becomes the next big culture,” Leon-Rivera said.Mentors, including Anthony Zuiker, the creator of the CSI franchise, and Roberto Orci, the writer and producer of Sleepy Hollow, will be paired with the finalists.“Now that we’ve launched and have begun to witness the overwhelmingly positive response to this project, I’m even more excited to see what kinds of concepts and scripts the world has in store for us all,” Zlotoff said.By creating a national marketing campaign, Smith said he hopes to raise the profile of women in engineering.“There is an entire generation of great storytellers, and we want them to think of writing female engineering characters. Because if you see strong female engineers, it’s easier to imagine yourself [as] one,” Smith said.last_img read more

LA Dodgers experiment with postseason roles in win over San Diego Padres

first_imgSAN DIEGO >> Brett Anderson, a starting pitcher to this point in his existence as a Dodger, threw 2 1/3 innings out of the bullpen Thursday. Another converted starter, Alex Wood, pitched the eighth inning. Julio Urias, who moved to the bullpen when the month began, threw three innings as a starter.In the most topsy-turvy act of all, the Dodgers knocked around a left-handed pitcher en route to a 9-4 victory over the San Diego Padres. That gave them a winning record — 22-21 — in games started by left-handed pitchers this season.In the words of Dick Enberg, who broadcasts his final Padres game Sunday: Oh my.If the Dodgers intend to fully exorcise their left-handed demons before the regular season ends, an ornery 6-foot-5 inch obstacle still stands in their way: Madison Bumgarner, who starts the opener of a three-game series against the Giants on Friday. That, and sorting out any postseason roster roles still to be determined, will be the Dodgers’ final order of business as the regular season ends. Meanwhile, the possibility of beginning the National League Division Series at home slipped further from their grasp Friday. The Washington Nationals beat the Arizona Diamondbacks earlier in the day. They lead the Dodgers by two games in the race to host the NLDS with three games left in the season.The Dodgers convincingly avoided a three-game sweep at the hands of the Padres, the fourth-place team in the National League West. Justin Turner had three of the Dodgers’ 15 hits, while Joc Pederson (2 for 5, two doubles), Carlos Ruiz (2 for 4) and Rob Segedin (2 for 3) added polish to their statistics.Whether he’s at home or on the road, pitching as a starter or reliever, Urias will be there when the playoffs begin.The 20-year-old left-hander allowed a double to Manuel Margot to begin the game, then didn’t allow another hit for three innings. Urias walked two batters and struck out five in what was likely the final appearance of his rookie season. He was removed after throwing 58 pitches. Newsroom GuidelinesNews TipsContact UsReport an Errorcenter_img If his next opponent is the Nationals, Urias will finish his first major league season with a 5-2 record and a 3.39 earned-run average in 18 games (15 starts) with the Dodgers.Anderson (1-2) was credited with the victory, his first since Oct. 1, 2015. He didn’t allow a run in his first relief appearance since an October 2013 division series game for the Oakland A’s.With the Dodgers trailing 2-1 in the fourth inning, Charlie Culberson jump-started a four-run rally with a double against Padres starter Christian Friedrich (5-12). Turner tied the game 2-2 with an RBI double, then scored on a wild pitch by left-handed reliever Jose Torres.Andre Ethier appeared as a pinch hitter for the ninth time this month. His RBI single in the eighth inning gave him three hits, a walk and two RBIs coming off the bench.Andrew Toles, who will be on the NLDS roster, singled in his only plate appearance off the bench before the announced crowd of 35,804 at Petco Park.The start of the game was delayed while the Padres honored Enberg.last_img read more