Ihopedwecandobusinesstogetherandlookingforwardtohearingfromyousoon.

Idaresaythatthepriceweoffercomparefavorablywithanyquotationyoucanobtainelsewhere.

Don'twashthosefossils!

StandardmuseumpracticecanwashawayDNA.

1.Washing,brushingandvarnishingfossils—allstandardconservationtreatmentsusedbymanyfossilhuntersandmuseumcuratorsalike—vastlyreducesthechancesofrecoveringancientDNA.

2.Instead,excavatorsshouldbehandlingatleastsomeoftheirbountywithgloves,andfreezingsamplesastheyarefound,dirtandall,concludesapaperintheProceedingsoftheNationalAcademyofSciencestoday.

3.AlthoughmanypalaeontologistsknowanecdotallythatthisisthebestwaytouptheoddsofextractinggoodDNA,Eva-MariaGeigloftheJacquesMonodInstituteinParis,France,andhercolleagueshavenowshownjusthowimportantconservationpracticescanbe.Thisinformation,theysay,needstobehammeredhomeamongthepeoplewhoareactuallyoutinthefielddiggingupbones.

4.Geiglandhercolleagueslookedat3,200-year-oldfossilbonesbelongingtoasingleindividualofanextinctcattlespecies,calledanaurochs.ThefossilsweredugupatasiteinFranceattwodifferenttimes—eitherin1947,andstoredinamuseumcollection,orin2004,andconservedinsterileconditionsat-20oC.

5.Theteam'sattemptstoextractDNAfromthe1947bonesallfailed.Thenewlyexcavatedfossils,however,allyieldedDNA.

6.Becausetheboneshadbeenburiedforthesameamountoftime,andinthesameconditions,theconservationmethodhadtobetoblamesaysGeigl."AsmuchDNAwasdegradedinthese57yearsasinthe3,200yearsbefore,"shesays.

Washin,washout

7.Becausemanypalaeontologistsbasetheirworkontheshapeoffossilsalone,theirmethodsofconservationarenotdesignedtopreserveDNA,Geiglexplains.

8.Thebiggestproblemishowtheyarecleaned.Fossilsareoftenwashedtogetheron-siteinalargebath,whichcanallowwater—andcontaminantsintheformofcontemporaryDNA—topermeateintotheporousbones."NotonlyistheauthenticDNAgettingwashedout,butcontaminationisgettingwashedin,"saysGeigl.

9.MostancientDNAspecialistsknowthisalready,saysHendrikPoinar,anevolutionarygeneticistatMcMasterUniversityinOntario,Canada.Butthatdoesn'tmeanthatbestpracticehasbecomewidespreadamongthosewhoactuallyfindthefossils.

10.GettingholdoffossilsthathavebeenpreservedwiththeirDNAinmindreliesoncloserelationshipsbetweenlab-basedgeneticistsandtheexcavators,sayspalaeogeneticistSvantePbooftheMaxPlanckInstituteforEvolutionaryAnthropologyinLeipzig,Germany.Andthatonlyoccursinexceptionalcases,hesays.

11.Pbo'steam,whichhasbeensequencingNeanderthalDNA,continuallyfacestheseproblems."WhenyouwanttostudyancienthumanandNeanderthalremains,there'sabigissueofcontaminationwithcontemporaryhumanDNA,"hesays.

12.Thisdoesn'tmeanthatallmuseumspecimensarefatallyflawed,notesPbo.TheNeanderthalfossilsthatwererecentlysequencedinhisownlab,forexample,hadbeenpartofamuseumcollectiontreatedinthetraditionalway.ButPboiskeentoseesamplesoffossilsfromeverymajorfindpreservedinlinewithGeigl'srecommendations—justincase.

Warmandwet

13.Geiglherselfbelievesthat,withcooperationbetweenbenchandfieldresearchers,preservingfossilsproperlycouldopenupavenuesofdiscoverythathavelongbeenassumedclosed.

14.Muchhumanculturaldevelopmenttookplaceintemperateregions.DNAdoesnotsurvivewellinwarmenvironmentsinthefirstplace,andcanvanishwhenfossilsarewashedandtreated.Forthisreason,Geiglsays,mostancientDNAstudieshavebeendoneonpermafrostsamples,suchasthewoollymammoth,oronremainsshelteredfromtheelementsincoldcaves—includingcavebearandNeanderthalfossils.

15.Betterconservationmethods,andafocusonfreshfossils,couldboostDNAextractionfrommoredelicatespecimens,saysGeigl.Andthatcouldshedmorelightonthestoryofhumanevolution.

(640wordsnature)

Glossary

Palaeontologists古生物学家

Aurochs欧洲野牛

Neanderthal(人类学)尼安德特人，旧石器时代的古人类。

Permafrost(地理)永冻层

Questions1-6

AnswerthefollowingquestionsbyusingNOMORETHANTHREEWORDSforeachanswer.

1.Howdidpeopletraditionallytreatfossils?

2.WhatsuggestionsdoGeiglandhercolleaguesgiveonwhatshouldbedonewhenfossilsarefound?

3.Whatproblemsmaybeposediffossilbonesarewashedon-site?NameONE.

4.WhatcharacteristicdofossilboneshavetomakethemsusceptibletobecontaminatedwithcontemporaryDNAwhentheyarewashed?

5.Whatcouldbebetterunderstoodwhenconservationtreatmentsareimproved?

6.Thepassagementionedseveralanimalspeciesstudiedbyresearchers.Howmanyofthemarementioned?

Questions7-11

Dothefollowingstatementsagreewiththeinformationgiveninthepassage?PleasewriteTRUEifthestatementagreeswiththewriterFALSEifthestatementdoesnotagreewiththewriterNOTGIVENifthereisnoinformationaboutthisinthepassage.

7.IntheirpaperpublishedintheProceedingsoftheNationalAcademyofSciences，GeiglandhercolleagueshaveshownwhatconservationpracticesshouldbefollowedtopreserveancientDNA.

8.ThefossilbonesthatGeiglandhercolleaguesstudiedareallfromthesameaurochs.

9.Geneticistsdon'thavetoworkonsite.

10.OnlynewlyexcavatedfossilbonesusingnewconservationmethodssuggestedbyGeiglandhercolleaguescontainancientDNA.

11.Paaboisstillworriedaboutthepotentialproblemscausedbytreatmentsoffossilsintraditionalway.

Questions12-13

CompletethefollowingthestatementsbychoosingletterA-Dforeachanswer.

12.“Thisinformation”inparagraph3indicates:

[A]ItiscriticaltofollowproperpracticesinpreservingancientDNA.

[B]ThebestwayofgettinggoodDNAistohandlefossilswithgloves.

[C]Fossilhuntersshouldwearhome-madehammerswhilediggingupbones.

[D]Manypalaeontologistsknowhowoneshoulddointreatingfossils.

13.ThestudyconductedbyGeiglandhercolleaguessuggests:

[A]thefactthatancientDNAcannotberecoveredfromfossilbonesexcavatedinthepast.

[B]thecorrelationbetweentheamountofburyingtimeandthatoftherecoveredDNA.

[C]thepaceatwhichDNAdegrades.

[D]thecorrelationbetweenconservationpracticesanddegradationofDNA.

newweapontofightcancer

1.Britishscientistsarepreparingtolaunchtrialsofaradicalnewwaytofightcancer,whichkillstumoursbyinfectingthemwithviruseslikethecommoncold.

2.Ifsuccessful,virustherapycouldeventuallyformathirdpillaralongsideradiotherapyandchemotherapyinthestandardarsenalagainstcancer,whileavoidingsomeofthedebilitatingside-effects.

3.LeonardSeymour,aprofessorofgenetherapyatOxfordUniversity,whohasbeenworkingonthevirustherapywithcolleaguesinLondonandtheUS,willleadthetrialslaterthisyear.CancerResearchUKsaidyesterdaythatitwasexcitedbythepotentialofProfSeymour’spioneeringtechniques.

4.Oneofthecountry’sleadinggeneticists,ProfSeymourhasbeenworkingwithvirusesthatkillcancercellsdirectly,whileavoidingharmtohealthytissue."Inprinciple,you’vegotsomethingwhichcouldbemanytimesmoreeffectivethanregularchemotherapy,"hesaid.

5.Cancer-killingvirusesexploitthefactthatcancercellssuppressthebody’slocalimmunesystem."Ifacancerdoesn’tdothat,theimmunesystemwipesitout.Ifyoucangetavirusintoatumour,virusesfindthemaverygoodplacetobebecausethere’snoimmunesystemtostopthemreplicating.Youcanregarditasthecancer’sAchilles’heel."

6.Onlyasmallamountofthevirusneedstogettothecancer."Theyreplicate,yougetamillioncopiesineachcellandthecellburstsandtheyinfectthetumourcellsadjacentandrepeattheprocess,"saidProfSeymour.

7.Preliminaryresearchonmiceshowsthatthevirusesworkwellontumoursresistanttostandardcancerdrugs."It’saninterestingpossibilitythattheymayhaveanadvantageinkillingdrug-resistanttumours,whichcouldbequitedifferenttoanythingwe’vehadbefore."

8.Researchershaveknownforsometimethatvirusescankilltumourcellsandsomeaspectsoftheworkhavealreadybeenpublishedinscientificjournals.Americanscientistshavepreviouslyinjectedvirusesdirectlyintotumoursbutthistechniquewillnotworkifthecancerisinaccessibleorhasspreadthroughoutthebody.

9.ProfSeymour’sinnovativesolutionistomaskthevirusfromthebody’simmunesystem,effectivelyallowingthevirusestodowhatchemotherapydrugsdo-spreadthroughthebloodandreachtumourswherevertheyare.Thebighurdlehasalwaysbeentofindawaytodelivervirusestotumoursviathebloodstreamwithoutthebody’simmunesystemdestroyingthemontheway.

10."Whatwe’vedoneismakechemicalmodificationstothevirustoputapolymercoataroundit-it’sastealthviruswhenyouinjectit,"hesaid.

11.Afterthestealthvirusinfectsthetumour,itreplicates,butthecopiesdonothavethechemicalmodifications.Iftheyescapefromthetumour,thecopieswillbequicklyrecognisedandmoppedupbythebody’simmunesystem.

12.Thetherapywouldbeespeciallyusefulforsecondarycancers,calledmetastases,whichsometimesspreadaroundthebodyafterthefirsttumourappears."There’sanawfulstatisticofpatientsinthewest...withmalignantcancers;75%ofthemgoontodiefrommetastases,"saidProfSeymour.

13.Twovirusesarelikelytobeexaminedinthefirstclinicaltrials:adenovirus,whichnormallycausesacold-likeillness,andvaccinia,whichcausescowpoxandisalsousedinthevaccineagainstsmallpox.Forsafetyreasons,bothwillbedisabledtomakethemlesspathogenicinthetrial,butProfSeymoursaidheeventuallyhopestousenaturalviruses.

14.Thefirsttrialswilluseuncoatedadenovirusandvacciniaandwillbedeliveredlocallytolivertumours,inordertoestablishwhetherthetreatmentissafeinhumansandwhatdoseofviruswillbeneeded.Severalmoreyearsoftrialswillbeneeded,eventuallyalsoonthepolymer-coatedviruses,beforethetherapycanbeconsideredforuseintheNHS.Thoughtheapproachwillbeexaminedatfirstforcancersthatdonotrespondtoconventionaltreatments,ProfSeymourhopesthatonedayitmightbeappliedtoallcancers.

Questions1-6

Dothefollowingstatementsagreewiththeinformationgiveninthereadingpassage?Forquestions1-6write

TRUEifthestatementagreeswiththeinformation

FALSEifthestatementcontradictstheinformation

NOTGIVENifthereisnoinformationonthisinthepassage

1.Virustherapy,ifsuccessful,hasanadvantageineliminatingside-effects.

2.CancerResearchUKisquitehopefulaboutProfessorSeymour’sworkonthevirustherapy.

3.Viruscankillcancercellsandstopthemfromgrowingagain.

4.Cancer’sAchilles’heelreferstothefactthatvirusmaystaysafelyinatumorandreplicate.

5.Toinfectthecancercells,agooddealofvirusesshouldbeinjectedintothetumor.

6.Researchesonanimalsindicatethatviruscouldbeusedasanewwaytotreatdrug-resistanttumors.

Question7-9

Basedonthereadingpassage,choosetheappropriateletterfromA-Dforeachanswer.

7.Informationaboutresearchesonviruseskillingtumorcellscanbefound

(A)onTV

(B)inmagazines

(C)oninternet

(D)innewspapers

8.Totreattumorsspreadingoutinbody,researcherstryto

(A)changethebody’immunesystem

(B)injectchemotherapydrugsintobloodstream.

(C)increasetheamountofinjection

(D)disguisethevirusesonthewaytotumors.

9.Whenthechemicalmodifiedvirusintumorreplicates,thecopies

(A)willsoonescapefromthetumorandspreadout.

(B)willbewipedoutbythebody’simmunesystem.

(C)willbeimmediatelyrecognizedbytheresearchers.

(D)willeventuallystopthetumorfromspreadingout.

Questions10-13

Completethesentencesbelow.Chooseyouranswersfromthelistofwords.Youcanonlyuseeachwordonce.

NBTherearemorewordsinthelistthanspacessoyouwillnotusethemall.

Inthefirstclinicaltrials,scientistswilltryto……10……adenovirusandvaccinia,soboththeviruseswillbelesspathogenicthanthe……11…….Theseuncoatedviruseswillbeapplieddirectlytocertainareastoconfirmsafetyonhumanbeingsandtheright……12……needed.Theexperimentswillfirstlybe……13……tothetreatmentofcertaincancers

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