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

Regretting Surrogacy

first_imgABC News 20 August 2014New film highlights women who agree to be surrogates, then struggle with giving up babies after birth.http://abcnews.go.com/Nightline/video/conception-controversy-regretting-surrogacy-25048043?utm_source=CBC+Newsletter&utm_campaign=bdd728be20-2014_08_20_Nightline&utm_medium=email&utm_term=0_56f2fc828e-bdd728be20-70772305&mc_cid=bdd728be20&mc_eid=e458a49e38last_img

Van Gaal nears decision on players

first_imgLouis van Gaal will sit down with his players after their tour and tell them whether they have a future at Manchester United. Van Gaal and his 25-man squad fly back to Manchester in the early hours of Tuesday morning following their final game of the US tour against Liverpool. Van Gaal has racked up morale-boosting wins over the Los Angeles Galaxy, Roma, Inter Milan and Real Madrid, but he is still unhappy with certain aspects of his squad. Van Gaal thinks Van Persie is unlikely to be fit to face Swansea on August 16, but the other two could be in contention for United’s Barclays Premier League opener, depending on how they react to training. “I have to look at Robin van Persie if he is coming back or not,” said Van Gaal, who coached the striker at the World Cup. “But if you have three weeks holiday and only four days training before the Valencia friendly (on August 12) you are not fit enough. “For the first game in the Premier League it’s possible but I don’t think so.” United’s money-spinning tour of the US started amid a blaze of publicity in Los Angeles, but two-and-a-half weeks later, their presence in the US is a lot more low-key. Only a couple of hundred invited guests turned up at the Sun Life Stadium to watch United’s final training session in America. The session was more of a warm-down as they only played Real Madrid on Saturday night. On the eve of the match, Liverpool manager Brendan Rodgers said Van Gaal is facing a totally different challenge to any other he has faced in his long and successful career. Van Gaal, who has won titles in Spain, Holland and Germany, says he is up to the challenge. “That’s why I’m here,” he said. “Maybe he is right because I have to experience that but I was also in Spain and in my first year I won three titles, in Germany I won two titles. “If I win one here we will all be happy.” Van Gaal is expected to ring in the changes for the final in Miami, which kicks off at 1am BST on Tuesday. The winner takes home a prize of one million US dollars (£600,000). Javier Hernandez, Shinji Kagawa and Wilfried Zaha face uncertain futures after limited playing time in America while Marouane Fellaini and Anderson, who have not made the trip, could also be shown the door. Van Gaal wants to tell his players whether they have made the cut well before the transfer window closes so he will approach them individually and inform them of their fate when they get back to England. “I shall make judgements after the tour,” the United boss said. “I have let all the players play so I know now more than I did before. “But in football you have to judge. Always you have to give a chance to a player to make a transfer when you see that his perspective is not so high to play. “You have to say it in advance. When you say it on August 31st it’s too late. I shall say to the players what I think after the tour.” Van Gaal has sent coach Marcel Bout back to England to work with the likes of Robin van Persie, Adnan Januzaj, and Fellaini, who have been given time off following their exploits at the World Cup. “They (Van Persie, Fellaini and Januzaj) have already trained. I sent Marcel Bout back to train them, along with Nicky Butt,” Van Gaal said. Press Associationlast_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