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

Temple game produces only two arrests

first_imgSaturday’s football home opener against Temple University brought more than 100,000 people to campus, and Director of Game Day Operations Mike Seamon said the day’s overall atmosphere was “absolutely elevated.” “It was definitely above what we would consider a normal standard for a typical opening day,” Seamon said. “Everything was energized … because people are excited about the season and there’s a key interest in Notre Dame football. [This weekend] was bigger than any of the home openers in the past two or three years.” Seamon said the stadium boasted a sellout crowd of approximately 82,000 people, and even more fans flooded campus Saturday for other game day events. Nearly 12,000 people attended Friday’s pep rally and about 5,000 participated in the tour of the stadium and tunnel on Friday, he said.  The number one concern for Saturday’s game was the weather forecast, Seamon said. “The weather was predicted to be very hot and humid, so we put together a big heat and humidity plan,” he said. “We put together a cooling station outside Gate A and worked with the first aid team to be sure we were prepared.  “It was a tough day weather-wise, but it could have been worse, thankfully. We had a good plan in place, and people did a good job watching out for each other so it went fairly well.” Phil Johnson, chief of police for Notre Dame Security Police, said the flow of traffic near campus on game day went smoothly despite construction. “Area police agencies worked cooperatively to promote public safety and smooth traffic flow,” Johnson said. “Everything with the new Douglas Road went very well. … Construction south of campus along South Bend Avenue didn’t adversely impact game day traffic.” Seamon said the outbound traffic was especially smooth after the game because not everybody stayed until the very end. “The game wasn’t very close, so a lot of people didn’t feel like they needed to stay until the last play,” he said. “It didn’t go down to the last minute so people left at different times, which really sped things up.” Police made two custodial arrests on campus Saturday, Johnson said. “One [arrest] was inside the stadium and one was outside,” Johnson said. “Both were arrested for public intoxication and disorderly conduct.” Seamon said another main concern was the implementation of the stadium’s new bag policy. “People were very receptive and understanding [of the policy] especially in light of the Boston Marathon tragedy,” he said. “We found that if you did not bring a bag, you got into the stadium quicker and that’s what we’d recommend in the future if you want to get in quickly.”last_img read more

Water polo looks for NCAA tournament berth

first_imgFreshman goalie Nic Porter makes a save against UCLA. He earned MPSF Newcomer of the Week with nine saves. (Josh Dunst | Daily Trojan)After last Saturday’s win against UCLA, the men’s water polo team will begin its postseason this weekend in home waters for the Mountain Pacific Sports Federation Tournament. Tournament play begins Friday at 9 a.m. and will conclude with the championship match at 1 p.m. Sunday.The Trojans are looking for an NCAA berth and will enter the tournament as the No. 2 seed behind Stanford. USC has a bye in the first round and will play Cal, Penn State Behrend or Austin College in the semifinals on Saturday, depending on Friday’s results.  A Trojan victory on Saturday would mark USC’s 12th consecutive win for their 20-win season. Last year, the team finished 27-4 overall, winning the 2017 MPSF Tournament and reaching the NCAA final for the 13th straight year. The 2018 Trojans are hoping to continue their winning streak and add a 10th NCAA title to the storied program’s collection of trophies. Just days after the team collected its 11th straight victory, freshman goalie Nic Porter earned the Trojans’ ninth MPSF Newcomer of the Week award of 2018. Porter had nine saves against UCLA, including a vital stop in the final minute to secure the victory. His ninth save secured an 11-11 tie entering the final minute of regulation. Now a four-time award winner, Porter matches freshman driver Hannes Daube’s tally of honors to date. Freshman guard Sam Krutonog also has a win to his name, giving USC nine of the 11 newcomer accolades doled out by the conference this season. The Trojans are currently leading the MPSF both offensively and defensively with 16.34 goals scored per game and just 5.34 goals-against per game. “We always want to improve our efforts at both ends of the pool,” Porter said. “Our offense has been firing lately, but we were disappointed to concede 11 goals against UCLA last time out. There’s been an added emphasis on defense this week and this is due to the attacking threats that Cal’s team poses.”USC beat Cal twice during the regular season, and the teams are expected to face off on Saturday. The team aims to claim its third consecutive MPSF Tournament crown and extend its streak of trips to the NCAA final to 14 in a row. “The team has had success in the MPSF tournament in recent years, so the older players and coaches are familiar with how to be successful in this tournament,” Porter said. “We come into this tournament with a lot of confidence, but determined to play some of our best water polo and qualify for the NCAAs.”last_img read more


first_imgOne man believes that Donegal will lift Sam Maguire again this year and he’s even written it in stone.Hundreds of people have been to see Anthony Barrett’s Stone Sam in Newtowncunningham!In fact, farmer Anthony Barrett has spent two months building a huge stone version of the famous All-Ireland trophy and placed it on his land.The cup, which stands more than 12 feet tall, has become a local tourist attraction for people from miles around. It took four tonnes of cement and a huge steel girder to keep the cup in place and Anthony reckons it weights at least 20 tonnes.Anthony, from Newtowncunningham, believes he will be putting the green and yellow ribbons of Donegal on his stone cup come Sunday after they beat Dublin.“I have a lot of time for the Dubs and I think they are a great bunch of fellas who play a lovely brand of football.“But I think it’s destiny that Donegal will beat them and go on to win Sam. I have the ribbons ready and they will go on the cup on Sunday afternoon,” he said. The Donegal team are due to visit his farm at Newtown to see the amazing stone cup but Anthony says he is prepared to wait until before the All-Ireland final.He admits that some of his neighbours think he is “stone mad” but he wouldn’t have it any other way.“A lot of people come and see the cup and it’s a great talking point. Of course some of them think I’m stone mad.“I have no training in stonework but I just started it one day and decided to keep going with another lad helping me.“I’m a big GAA fan and I just thought it would look nice on the land. “A lot of people said it would never stay up but like Donegal on Sunday, it’ll still be standing after the final whistle,” he laughed.COUNTDOWN TO CROKER – FARMER BELIEVES DONEGAL WIN IS WRITTEN IN STONE! was last modified: August 28th, 2014 by StephenShare this:Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Reddit (Opens in new window)Click to share on Pocket (Opens in new window)Click to share on Telegram (Opens in new window)Click to share on WhatsApp (Opens in new window)Click to share on Skype (Opens in new window)Click to print (Opens in new window)Tags:Anthony BarrettdonegalGAASam Maguirestonelast_img read more