题目内容:
Questionsarebasedonthefollowingpassage. Itisawisefatherthatknowshisownchild,buttodayamancanboosthispaternal(fatherly)wisdom--oratleastconfirmthathe'sthekid'sdad.Allheneedstodoisshellout$30forpaternitytestingkit(PTK)athislocaldrugstore--andanother$120togettheresults.
Morethan60,000peoplehavepurchasedthePTKssincetheyfirstbecomeavailablewithoutprescriptionslastyears,accordingtoDougFogg,chiefoperatingofficerofIdentigene,whichmakestheover-the-counterkits.MorethantwodozencompaniessellDNAtestsdirectlytothepublic,ranginginpricefromafewhundreddollarstomorethan$2,500.
Amongthemostpopular:paternityandkinshiptesting,whichadoptedchildrencanusetofindtheirbiologicalrelativesandfamiliescanusetotrackdownkidsputupforadoption,DNAtestingisalsothelatestrageamongpassionategenealogists--andsupportsbusinessesthatoffertosearchforafamily'sgeographicroots.
Mosttestsrequirecollectingcellsbywebbingsaliva(唾液)inthemouthandsendingittothecompanyfortesting.AlltestsrequireapotentialcandidatewithwhomtocompareDNA.
Butsomeobserversareskeptical."Thereisakindoffalseprecisionbeinghawkedbypeopleclaimingtheyaredoingancestrytesting,"saysTreyDuster,aNewYorkUniversitysociologist.Henotesthateachindividualhasmanyancestors--numberinginthehundredsjustafewcenturiesback.Yetmostancestrytestingonlyconsidersasinglelineage(世系),eithertheYchromosome(染色体)inheritedthroughmeninafather'slineormitochondrial(线粒体)DNA,whichispasseddownonlyfrommothers.ThisDNAcanrevealgeneticinformationaboutonlyoneortwoancestors,eventhough,forexample,justthreegenerationsbackpeoplealsohavesixothergreat-grandparentsor,fourgenerationsback,14othergreat-great-grandparents.
Criticsalsoarguethatcommercialgenetictestingisonlyasgoodasthereferencecollectionstowhichasampleiscompared.Databasesusedbysomecompaniesdon'trelyondatacollectedsystematicallybutratherlumptogetherinformationfromdifferentresearchprojects.ThismeansthataDNAdatabasemayhavealotofdatafromsomeregionsandnotothers,soaperson'stestresultsmaydifferdependingonthecompanythatprocessestheresults.
Accordingtothepassage,whatisPTKusedto? A.Tolocateone'sbirthplace.
B.Topromotegeneticresearch.
C.Tofindoutifoneisthefatherofachild.
D.Tohelpimproveone'sintelligence.
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