An aquarium accident may have given this crayfish the DNA to take over the world

first_imgThe genome of the marbled crayfish reveals its history and its secret to success.  It sounds like a bad monster movie plot: A 10-legged mutant creature that reproduces asexually, escapes from confinement in Germany, and quietly begins a global invasion. Within 2 decades, clones of the voracious animal spread through Europe and Africa, bringing devastation to ecosystems and threatening native species.That appears to be the strange-but-true story of the marbled crayfish, an invasive freshwater species suspected to have been created through a reproductive accident in an aquarium around 1995. A new analysis of the crustacean’s genome supports this unlikely origin and may help explain how the animal has subsequently spread and adapted to so many new environments.The crayfish’s unusual evolution could also suggest a strategy to tackle a more infamous clonal monster: cancer. “In many ways, the invasive expansion of [the marbled crayfish] is analogous to a cancerous lineage spreading asexually at the expense of its host,” says Jean-François Flot, an evolutionary genomicist at the Free University of Brussels who was not involved with the work. Sign up for our daily newsletterGet more great content like this delivered right to you!Country *AfghanistanAland IslandsAlbaniaAlgeriaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelgiumBelizeBeninBermudaBhutanBolivia, Plurinational State ofBonaire, Sint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBrunei DarussalamBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongoCongo, The Democratic Republic of theCook IslandsCosta RicaCote D’IvoireCroatiaCubaCuraçaoCyprusCzech RepublicDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland Islands (Malvinas)Faroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and Mcdonald IslandsHoly See (Vatican City State)HondurasHong KongHungaryIcelandIndiaIndonesiaIran, Islamic Republic ofIraqIrelandIsle of ManIsraelItalyJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKorea, Democratic People’s Republic ofKorea, Republic ofKuwaitKyrgyzstanLao People’s Democratic RepublicLatviaLebanonLesothoLiberiaLibyan Arab JamahiriyaLiechtensteinLithuaniaLuxembourgMacaoMacedonia, The Former Yugoslav Republic ofMadagascarMalawiMalaysiaMaldivesMaliMaltaMartiniqueMauritaniaMauritiusMayotteMexicoMoldova, Republic ofMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorwayOmanPakistanPalestinianPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalQatarReunionRomaniaRussian FederationRWANDASaint Barthélemy Saint Helena, Ascension and Tristan da CunhaSaint Kitts and NevisSaint LuciaSaint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSamoaSan MarinoSao Tome and PrincipeSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSint Maarten (Dutch part)SlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia and the South Sandwich IslandsSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyrian Arab RepublicTaiwanTajikistanTanzania, United Republic ofThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUnited KingdomUnited StatesUruguayUzbekistanVanuatuVenezuela, Bolivarian Republic ofVietnamVirgin Islands, BritishWallis and FutunaWestern SaharaYemenZambiaZimbabweI also wish to receive emails from AAAS/Science and Science advertisers, including information on products, services and special offers which may include but are not limited to news, careers information & upcoming events.Required fields are included by an asterisk(*)The marbled crayfish is the only decapod crustacean that reproduces asexually, with the all-female species making clones of itself from eggs unfertilized by sperm. It has been thought to have arisen when two slough crayfish, imported from Florida for the aquarium trade in Germany, mated.Since its discovery in 1995 in Germany, the marbled crayfish has spread across Europe and into Africa in huge numbers. “They eat anything—rotten leaves, snails or fish broods, small fish, small insects,” says Frank Lyko, a molecular geneticist at the German Cancer Research Center in Heidelberg. “This crayfish is a serious pest,” adds Gerhard Scholtz, an evolutionary biologist at Humboldt University in Berlin, who has tracked its rapid spread across the globe, including Madagascar, where its success threatens the existence of the seven crayfish native to that island country. The European Union banned the species: It must not be sold, kept, distributed, or released to the wild.Five years ago, Lyko became interested in the marbled crayfish, now called Procambarus virginalis, because he thought its newly evolved asexual nature might parallel how a normal cell turns cancerous and begins generating clones of itself. In particular, he wanted to study the genomes of marbled crayfish to uncover basic mechanisms underlying epigenetics, the binding of molecules to DNA that can drive tumor growth and help cancer spread.So, Lyko and his colleagues sequenced genomes of about a dozen marbled crayfish from different parts of the world and performed less detailed genetic analyses of two dozen more from across Madagascar. At 3.5 billion DNA bases in length, the crustacean’s genome is bigger than the human genome, but contains about the same number of genes, 21,000, they report today in Nature Ecology & Evolution. This is the first genome of a decapod, a group of 10-legged crustaceans that includes shrimp, lobsters, prawns, and crabs, as well as crayfish. “This [work] opens the way for comparative genomics and identification of [unique features] in this group of ecological and economically important species,” says Etienne Danchin, an evolutionary biologist at the National Institute of Agricultural Research in Sophia-Antipolis, France, who was not involved with the research.The study also “provides clues about how this genome arose and may help conservationists better track the spread of this invasive species,” Shotz says.As suggested by some preliminary evidence, the marbled crayfish has three sets of 92 chromosomes, not the usual two, and each set is essentially a version of the chromosomes belonging to the slough crayfish (P. fallax). Two of the three sets of chromosomes are virtually identical, but the third is different enough that Lyko’s team concludes the marbled crayfish likely arose from the mating of two slough crayfish from different regions of the world thrown together in an aquarium. One must have had an abnormal egg or sperm that retained two copies of its chromosomes instead of the usual single set that is in such germ cells, Lyko explains. The bringing together of the two distant slough crayfish enhanced the genetic variation within the new clonal “species.” Such a union “would never happen in the wild,” he asserts.Schotz isn’t totally persuaded that the genomic pile-up happened inside an aquarium, versus two slough crayfish meeting in the wild. “It is mere speculation that it originated in captivity,” he says. But the analysis of marbled crayfish DNA from across Europe and Africa, he says, ”shows that all these crayfish are clones—with identical genomes the world over.”More important than the crustacean’s origin may be that this clone thrives in a wide variety of freshwater habitats, with different temperatures, salinities, and acidity. Clones are supposed to be at a disadvantage because they lack the genetic variation to adapt to new situations. But, “This paper suggests that an animal species can rapidly invade a large geographical area despite reproducing without sex and being clonal,” Danchin says.The marbled crayfish’s three sets of chromosomes may be key, containing enough variety for adapting to different conditions. Danchin studies a very successful plant parasite, a nematode that reproduces asexually and also has three sets of chromosomes.Susan Adams, an aquatic ecologist with the U.S. Forest Service’s Southern Research Station in Oxford, Mississippi, agrees. Work in other organisms shows that having an extra set of chromosomes can boost the number of young and may help the clones adjust to new environments. “Greater adaptability is expected to enhance invasion success,” she says.A further advantage, Adams says: A clone can establish a new population starting with just one individual. “It is interesting to contemplate the global, ecological implications of an exceedingly rare evolutionary event arising in someone’s aquarium.” *Correction, 6 February, 10:20 a.m.: An earlier version of this story incorrectly stated that the marbled crayfish is the only crustacean that reproduces asexually. By Elizabeth PennisiFeb. 5, 2018 , 11:00 AM Huetter, C./picture alliance/Arco Images G/Newscom An aquarium accident may have given this crayfish the DNA to take over the worldlast_img read more

New Brunswick Tories prepare for power after Liberal government falls

first_imgFREDERICTON – Five weeks after New Brunswickers went to the polls, Tory Leader Blaine Higgs has become the premier-designate — and is promising to move quickly.“People of the province should feel comfortable that the system worked, it just took a little longer,” Higgs said after meeting with Lt.-Gov. Jocelyne Roy Vienneau late Friday, hours after Brian Gallant’s Liberals fell on a confidence vote.She asked if the Progressive Conservative leader had the confidence to form government, and Higgs said he told her that he did.Afterward, Higgs struck an optimistic tone as he spoke to reporters.“I guess the next step begins,” Higgs said.“I believe our province can be in first place in all categories. And I believe that opportunity is right before us today.”Gallant, whose government fell when the legislature voted against the throne speech, said he was unsure about his own political future, but he wished the Tories luck.“Their success will be New Brunswick’s success,” he said.Higgs said he wants the transition to occur as quickly as possible, with a cabinet by late next week and a throne speech before the end of the month.“The throne speech won’t be a shopping list. It will be a priority list and it will be focused on some big items we can agree on,” Higgs said.“We will set lofty goals and achieve them. We don’t need more taxes, we need results.”The Tories won 22 seats in the September election — one more than the Liberals — while the Greens and People’s Alliance each won three seats.Gallant sought to survive with a minority government by adding many of the opposition’s campaign promises to his party’s throne speech earlier this week, but his party’s fate was sealed Thursday when both the Tories and People’s Alliance said they’d vote to defeat it.Higgs said he believes his minority government can survive four years by producing results.Its success will depend on support from the opposition parties, and that has thrown the spotlight on language rights in Canada’s only official bilingual province.Higgs said Friday his priority would be to address a shortage of paramedics, where the failure to meet language requirements has left some ambulances unstaffed.He said francophones should not be concerned by his government’s approach.“They shouldn’t be worried at all. They should be grateful that we’re going to provide the health care they demand all across the province as an interim measure to meet the language requirements that we have,” he said.The People’s Alliance, which has agreed to prop up the Tories for at least 18 months, put bilingualism and service duality front and centre in their campaign.Gallant said Friday it was important parties don’t use the issue as a “political weapon.”He said it appeared the election results — which saw the Liberals dominate the largely francophone north and the Tories and People’s Alliance do better in the mostly anglophone south — suggested the province is divided along regional and linguistic lines.But he said people should not be taken in by those apparent divisions.“What binds us together is greater than what drives us apart … We’re all New Brunswickers.”Gallant said he wished he had done more to promote unity and bilingualism.“I will not pretend that we were a perfect government, but we were a good government.”People’s Alliance Leader Kris Austin said his party has agreed to support the Tories to provide some stability to the legislature.However, he said his members will be free to vote their conscience on bills.“We are in nobody’s back pocket, but in a minority government you do have to work together and we’ve agreed to do that with Mr. Higgs,” Austin said.Austin said his first priority is to get the new Tory government to address the ambulance issue.Green Leader David Coon and his two members voted to support the Liberal throne speech, which included many of his party’s campaign promises.“Our message to the Conservatives is that it’s important that they include those things in their throne speech, and we’ll be working hard to make sure that happens,” Coon said.Gallant said he and his wife are reflecting on what’s next — whether he serve as opposition leader or take a different path.“I still have a burning desire to make a difference, there’s no question about that,” he told reporters.last_img read more

Disney will launch a branded ondemand service on

first_imgDisney will launch a branded on-demand service on the Lovefilm streaming service in the UK.Disney inked a deal with BSkyB earlier this year that gave it the latest movie titles, exclusively, in the first pay TV window for a the new Sky Movies Disney service and for the pay TV operator’s mobile and on-demand services.Disney Movies on Demand on Lovefilm will offer its subs the chance to access a raft of the studio’s classic and newer features and titles include Wall-E, Ratatouille, Chronicles of Narnia: Prince Caspian, Dumbo and Bedknobs and Broomsticks.Lovefilm already has a programming deal with Disney, but these titles will be added in a branded section on its service as well as being available as part of the wider Lovefilm library. It launches today.Simon Morris, chief marketing officer at Lovefilm said: We are thrilled to enhance our relationship with the launch of Disney Movies on Demand, and even more excited about bringing our members so much new content in the process.”last_img read more

Multiplatform video management specialist Saffron

first_imgMulti-platform video management specialist Saffron Digital has named Leen Segers as sales manager for EMEA. Segers’ appointment follows the naming of former Brightcove sales executive Enda Parker, also as EMEA sales manager, three months ago. Segers was previously a media executive with Kaltura.last_img

Jørgen Madsen Lindemann MTG president and CEO Mo

first_imgJørgen Madsen Lindemann, MTG president and CEO.Modern Times Group (MTG) has decided to write down the value of its Ukrainian pay TV service, Viasat Ukraine, because of continuing economic uncertainty in the country. MTG is writing down 100% of the value of the goodwill value of its 85% stake in the platform via Viastrong Holding. The company said it will include net non-recurring charges of SEK154 million (€17 million) related to the stake in its second-quarter results. The charges comprise a SEK160 million non-cash net impairment related to Viasat Ukraine and SEK70 million of organizational and restructuring costs, offset by a SEK76 million net gain from the recently completed sale of an 80% stake in Swedish open-access fibre-to-the-home network operator Zitius to TeliaSonera.According to the company, the decision was taken due to the uncertain economic outlook in Ukraine and the devaluation of the Hryvnia. Viasat Ukraine accounted for less than 1% of MTG’s net sales in 2013.MTG said its organizational restructuring, costing SEK70 million, would deliver annual cost savings of approximately SEK40 million, which would be reinvested in business intelligence and data analysis.“The impairment of the Ukrainian assets reflects the current situation, but make no mistake that we remain committed to the operations and see substantial long term potential for the business, not least given the scale of the country and the upcoming TV digitalisation process,” said Jørgen Madsen Lindemann, MTG president and CEO.“The sale of Zitius in Sweden has generated a healthy return on investment for us, and the broader changes we have made are all about optimising our set-up so that we can continue to invest in the Group’s growth and development.”last_img read more