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.

Thelocalgovernmentwill_____morecollegesformorestudentstoreceivehighereducation.

-----AheavysnowhitmostofthepartsofChinainJanuary,2008.

-----____________terriblenews!

Howshopscanexploitpeople'sherdmentalitytoincreasesales

1.ATRIPtothesupermarketmaynotseemlikeanexerciseinpsychologicalwarfare—butitis.Shopkeepersknowthatfillingastorewiththearomaoffreshlybakedbreadmakespeoplefeelhungryandpersuadesthemtobuymorefoodthantheyhadintended.Stockingthemostexpensiveproductsateyelevelmakesthemsellfasterthancheaperbutlessvisiblecompetitors.Nowresearchersareinvestigatinghow“swarmintelligence”(thatis，howants，beesoranysocialanimal，includinghumans，behaveinacrowd)canbeusedtoinfluencewhatpeoplebuy.

2.AtarecentconferenceonthesimulationofadaptivebehaviourinRome，Zeeshan-ul-hassanUsmani，acomputerscientistfromtheFloridaInstituteofTechnology，describedanewwaytoincreaseimpulsebuyingusingthisphenomenon.Supermarketsalreadyencourageshopperstobuythingstheydidnotrealisetheywanted:forinstance，byplacingeverydayitemssuchasmilkandeggsatthebackofthestore，forcingshopperstowalkpastothertemptinggoodstoreachthem.MrUsmaniandRonaldoMenezes，alsooftheFloridaInstituteofTechnology，setouttoenhancethistendencytobuymorebyplayingontheherdinstinct.Theideaisthat，ifacertainproductisseentobepopular，shoppersarelikelytochooseittoo.Thechallengeistokeepcustomersinformedaboutwhatothersarebuying.

3.Entersmart-carttechnology.InMrUsmani'ssupermarketeveryproducthasaradiofrequencyidentificationtag，asortofbarcodethatusesradiowavestotransmitinformation，andeverytrolleyhasascannerthatreadsthisinformationandrelaysittoacentralcomputer.Asacustomerwalkspastashelfofgoods，ascreenontheshelftellshimhowmanypeoplecurrentlyintheshophavechosenthatparticularproduct.Ifthenumberishigh，heismorelikelytoselectittoo.

4.MrUsmani's“swarm-moves”modelappealstosupermarketsbecauseitincreasessaleswithouttheneedtogivepeoplediscounts.Anditgivesshoppersthesatisfactionofknowingthattheyboughtthe“right”product—thatis，theoneeveryoneelsebought.Themodelhasnotyetbeentestedwidelyintherealworld，mainlybecauseradiofrequencyidentificationtechnologyisnewandhasonlybeeninstalledexperimentallyinsomesupermarkets.ButMrUsmanisaysthatbothWal-MartinAmericaandTescoinBritainareinterestedinhiswork，andtestingwillgetunderwayinthespring.

5.Anotherrecentstudyonthepowerofsocialinfluenceindicatesthatsalescould，indeed，beboostedinthisway.MatthewSalganikofColumbiaUniversityinNewYorkandhiscolleagueshavedescribedcreatinganartificialmusicmarketinwhichsome14,000peopledownloadedpreviouslyunknownsongs.Theresearchersfoundthatwhenpeoplecouldseethesongsrankedbyhowmanytimestheyhadbeendownloaded，theyfollowedthecrowd.Whenthesongswerenotorderedbyrank，butthenumberoftimestheyhadbeendownloadedwasdisplayed，theeffectofsocialinfluencewasstilltherebutwaslesspronounced.Peoplethusfollowtheherdwhenitiseasyforthemtodoso.

6.InJapanachainofconvenienceshopscalledRanKingRanQueenhasbeenorderingitsproductsaccordingtosalesdatafromdepartmentstoresandresearchcompanies.Theshopssellonlythemostpopularitemsineachproductcategory，andtherankingsareupdatedweekly.Icosystem，acompanyinCambridge，Massachusetts，alsoaimstoexploitknowledgeofsocialnetworkingtoimprovesales.

7.Andthepsychologythatworksinphysicalstoresisjustaspotentontheinternet.OnlineretailerssuchasAmazonareadeptattellingshopperswhichproductsarepopularwithlike-mindedconsumers.Evenintheprivacyofyourhome，youcanstillbepartoftheswarm.

Questions1-6

Completethesentencesbelowwithwordstakenfromthereadingpassage.UseNOMORETHANTHREEWORDSforeachanswer.

1.Shopownersrealizethatthesmellof_______________canincreasesalesoffoodproducts.

2.Inshops，productsshelvedatamorevisiblelevelsellbettereveniftheyaremore_______________.

3.AccordingtoMr.Usmani，withtheuseof“swarmintelligence”phenomenon，anewmethodcanbeappliedtoencourage_______________.

4.Onthewaytoeverydayitemsatthebackofthestore，shoppersmightbetemptedtobuy_______________.

5.Ifthenumberofbuyersshownonthe_______________ishigh，othercustomerstendtofollowthem.

6.Usingthe“swarm-moves”model，shopownersdonothavetogivecustomers_______________toincreasesales.

-----Whataboutthepenyouboughtyesterday?

-----It____________well.Ilikeitverymuch.