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高三英語(yǔ)培優(yōu)外刊閱讀班級(jí):學(xué)號(hào):姓名:外刊精選I人高馬大的歐洲人:乳糖不耐也要喝牛奶上個(gè)月,新疆牛奶品牌麥趣爾產(chǎn)品抽檢不合格,再次引發(fā)了關(guān)于如何選好牛奶的網(wǎng)絡(luò)熱議。實(shí)際上,很多中國(guó)人其實(shí)根本不適合喝牛奶,因?yàn)橹袊?guó)人乳糖不耐受的比例要遠(yuǎn)高于歐美人。而國(guó)外的一項(xiàng)新研究發(fā)現(xiàn),原來(lái)我們印象中離不開(kāi)牛奶的歐洲人,很多也是乳糖不耐受的體質(zhì)。究竟為什么會(huì)有人乳糖不耐受?科學(xué)家還有哪些新發(fā)現(xiàn)?EarlyEuropeansCouldNotTolerateMilkbutDrankItAnyway,StudyFindsInmanyways,humansareweirdmammals.Andourrelationshipwithmilkisespeciallyweird.Ineverymammalianspecies,femalesproducemilktofeedtheiryoung.Thebabiesdigestthemilkwiththehelpofanenzymecalledlactase.Whentheyoungmammalsareweaned,theystopmakinglactase.Butitiscommonforourspeciestokeepconsumingmilkintoadulthood.What'smore,aboutone-thirdofpeoplecarrygeneticmutationsthatallowthemtoproducelactasethroughouttheirlives,makingiteasiertodigestmilk.Scientistshavelongsuspectedthatdairyconsumptionandthepersistenceoflactaserosetogetherinhumanhistory.Whenpeoplestartedherdingcattleandotherlivestocksome10,000yearsago,thetheorywent,thosewithamutationforlactasepersistencegainedanewsourceofcaloriesandprotein.Butanewstudysuggeststhatthetraditionalstorydoesnotholdup.ResearchershavefoundthatEuropeanswereconsumingmilkwithoutlactaseforthousandsofyears,despitethemiseryfromgasandcrampingitmighthavecaused.Overtheyears,scientistshavefoundmilkonthousandsofpotteryfragmentsacrossEuropeandneighboringregions.Forthenewstudy,thescientistsusedthisdatabasetocreateamapofmilkconsumptionoverthepast9,000years.【詞匯過(guò)關(guān)】請(qǐng)寫(xiě)出下面文單詞在文章中的中文意思。.tolerate['toIreit]v..weird[wiod]adj..consume[ksn'sju:m]v..cramp[kr<emp]v./n..fragment['frsegmsnt]n.【詞塊學(xué)習(xí)】請(qǐng)從文章中找到下面中文相對(duì)應(yīng)的文詞塊。.借助于,利用.使做某事更容易.長(zhǎng)期懷疑.理論是這樣的.(這個(gè)故事沒(méi)有)站得住腳拓展練習(xí)閱讀理解Modemmedicine'sabilitytokeepusalivemakesittemptingtothinkhumanevolutionmayhavestopped.ButifwelookattherateofourDNA'sevolution,wecanseethathumanevolutionhasn'tstopped一itmayevenbehappeningfasterthanbefore.EvolutionisagradualchangetotheDNAofaspeciesovermanygenerations.Itcanoccurbynaturalselection,whencertaintraitscreatedbygeneticchangeshelpanorganismsurviveorreproduce.Suchgenesarethusmorelikelytobepassedontothenextgeneration,sotheyincreaseinfrequencyinapopulation.Gradually,thesechangesandtheirassociatedtraitsbecomemorecommonamongthewholegroup.BylookingatglobalstudiesofourDNA,wecanseeevidencethatnaturalselectionhasrecentlymadechangesandcontinuestodoso.Thoughmodernhealthcaredisruptsakeydrivingforceofevolutionbykeepingsomepeoplealivelonger,incountrieswithoutaccesstogoodhealthcare,populationsarecontinuingtoevolve.Survivorsofinfectiousdiseaseoutbreaksdrivenaturalselectionbygivingtheirgeneticresistancetooffspring.OurDNAshowsevidenceforrecentselectionforresistanceofkillerdiseaseslikeLassafeverandmalaria.Selectioninresponsetomalariaremainsinregionswherethediseaseremainscommon.Humansarealsoadaptingtotheirenvironment.GenechangeallowinghumanstoliveathighaltitudeshavebecomemorecommoninpopulationsinTibet,Ethiopia,andtheAndes.ThespreadofgeneticchangesinTibetispossiblythefastestevolutionarychangeinhumans,occurringoverthepast3,000years.Thisrapidincreaseinfrequencyofamutatedgenethatincreasesbloodoxygencontentgiveslocalsasurvivaladvantageinhigheraltitudes,resultinginmoresurvivingchildren.Dietisanothersourceforadaptations.Studiesshowthatnaturalselectionfavoringachangeallowingadultstoproducelactase-theenzyme(酶)thatbreaksdownmilksugars-iswhysomegroupsofpeoplecandigestmilk.Over80percentofnorthwestEuropeanscan,butinpartsofEastAsia,wheremilkismuchlesscommonlydrunk,aninabilitytodigestlactoseisthenorm.Likehighaltitudeadaptation,selectiontodigestmilkhasevolvedmorethanonceinhumansandmaybethestrongestkindofrecentselection.Yet,despitethesechanges,naturalselectiononlyaffectsabout8percentofourgenome.Butscientistscan'texplainwhysomegenesareevolvingmuchfasterthanothers.WemeasurethespeedofgeneevolutionbycomparinghumanDNAwiththatofotherspecies.Onefast-evolvinggeneishumanacceleratedregion1(HARI),whichisneededduringbraindevelopment.ArandomsectionofhumanDNAisonaveragemorethan98percentidenticaltothechimpcomparator,butHARIissofastevolvingthatit'sonlyaround85percentsimilar.Thoughscientistscanseethesechangesarehappening-andhowquickly-westilldon'tfullyunderstandwhyfastevolutionhappenstosomegenesbutnotothers..Whichofthefollowingstatementsmaytheauthoragreewith?A.Evolutionoccursamongseveralpeopleovernight.B.Genesmaychangeandsomearebeneficialtopeople'slives.C.Evolutionisdonewhenthewholepopulationpossessesacertaingene.D.Thechangedgenesleadingtohighersurvivalratesarechosendeliberately..Theunderlinedword“disrupts”.Theauthorillustrateshumans'ongoingevolutionwiththefollowingexamplesEXCEPTthat.A.somepeoplecanresistinfectiousdiseaseslikemalariaB.childreninTibettoleratelivingenvironmentswiththinairC.northwesternEuropeansdigestlactosebetterthanEastAsiansD.thehumangeneHARIresemblesthatofachimptoalesserextent.Whichofthefollowingmayserveasthetitle?A.WhatIsNaturalSelection?B.AreHumansStillEvolving?C.WhyWillCertainGenesEvolve?D.HowDoMutatedGenesFunction?外刊精選答案【詞匯過(guò)關(guān)】請(qǐng)寫(xiě)出下面文單詞在文章中的中文意思。.tolerate['tDIreit]v.容許,允許;忍受;容忍.weird[wlsd]adj.奇怪的;詭異的;怪誕的.consume[kon'sju:m]v.消費(fèi);吃;消耗,耗費(fèi)4,cramp[kraemp]v./n.抽筋;痛性痙攣;(腹部)絞痛.fragment['frasgmont]n.碎片;片段【詞塊學(xué)習(xí)】請(qǐng)從文章中找到下面中文相對(duì)應(yīng)的文詞塊。l
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