主效基因抗病性（major gene resistance）
主效基因抗病性（major gene resistance）
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In July 1989, Dr.Fox and a team of scientists achieved a major scientific breakthrough.Fox discovered the gene (基因) that causes cystic fibrosis (膀胱纤维症) (CF).Many geneticists consider it 's one of the most significantdiscoveries in human genetics.Theresults of Fox work have helped scientists developtests that identify carriers of the CFgene.They hope his research could cure CF.a testhas been developed to identify peoplerrying the cystic fibrosis gene.The test isbased on knowing where the gene is locatedhe CF gene is a recessive gene.Thismeans a person can carry one copy of the gene andstill not be affected by the disease.However if this person has children with anothererson who carries the Cf genethere is a 25 chance that their children will inherit twoopies of the gene and sufferfrom the disease.The test identifies whether pat for cysticrents carrythe defective CF gene.Researchers are also using Fox discovery to find a curefibrosis.They areworking to produce a drug that will change the activity of the Cf geneId alsoattempting to replace the defective gene with one that functions properly.Itdifficultto produce a drug that changes the Cf gene but does not affect the 100000thergenes of human.But Fox discovery has at least given a chance for the cure othe CF1.A person with ( ) of a harmful recessive gene will be affectedA.one copyB two opiesC.no copiesD three copies.2.We can find answers to the following questions in the passage except ()A.Do people with CF live longer than they did in the past.B Describeused to treat CFC.Evaluate the current methods used to treat CFD.Describe the drugs used to treat CF3.The following statements are true except ()A Only one quarter of people will have chance to have the disease.B.Fox discovery help scientist develop tests that identify carriers of the CF geneC.Scientist has already produced a drug to CFD.To produce a drug is not easy because it should changes the CF gene but notaffectothers4.The word “recessive” (line 6) probably means ()A.hiddenB concealingC.faintD covered5.The best title for the passage would be ()A.Why People Have CFB.The Drugs Used to Treat CFC.The Methods of Curing CFD.TheSignificance of the DiscoveryCystic Fibrosis Gene
共用题干第一篇IQ-GeneIn the angry debate over how much of IQ comes from the genes that children inherit from parents and how much comes from experiences,one little fact gets overlooked:no one has identified any genes(other than those that cause retardation)that affect intelligence.So researchers led by Robert Plomin of London's Institute of Psychiatry decided to look for some.They figured that if you want to find a"smart gene",you should look in smart kids.They therefore examined the DNA of students like those who are so bright that they take college entrance exams four years early一and still score at Princeton-caliber levels.The scientists found what they sought."We have,"says Plomin, "the first specific gene ever associated with general intelligence."Plomin's colleagues drew blood from two groups of 51 children each,all 6 to 15 years old and living in six countries around Cleveland.In one group,the average IQ is 103.All the children are white.Isolating the blood cells,the researchers then examined each child's chromosome 6.Of the 37 land marks on chromosome 6 that the researchers looked for,one jumped out:a form of gene called IGF2R occurred in twice as many children in the high-IQ group as in the average group—32 percent versus 16 percent.The study,in the May issue of the journal Psychological Science concludes that it is this form of the IGF2R gene that contributes to intelligence.Some geneticists see major problems with the IQ-gene study.One is the possibility that Plomin's group fell for"chopsticks fallacy".Geneticists might think they've found a gene for chopsticks flexibility,but all they've really found is a gene more common in Asians than,say,Africans. Similarly, Plomin's IQ gene might simply be one that is more common in groups that emphasize academic achievement."What is the gene that they've found reflects ethnicity?"asks geneticist Andrew Feinberg of Johns Hopkins University."That alone might explain the link to intelligence,since IQ tests are known for being culturally sensitive and affected by a child's environment."And Neil Risch of Standford University points out that if you look for 37 genes on chromosome,as the researchers did, and find that one is more common in smarter kids,that might reflect pure chance rather than a causal link between the gene and intelligence.Warns Feinberg:"I would take these findings with a whole box of salt."Plomin's IQ-gene study is similar to the chopsticks gene finding in that_______.A:there may not be a causal link between gene and intelligenceB:there is close correlation between gene and intelligenceC:there may be a close relation between chopsticks flexibility and children's academic scoreD:there is not a close relation between chopsticks flexibility and children's academic score
共用题干IQ-geneIn the angry debate over how much of IQ comes from the genes that children inherit from par-ents and how much comes from experiences,one little fact gets overlooked:no one has identified any genes(other than those that cause retardation)that affect intelligence.So researchers led by Robert Plomin of London's Institute of Psychiatry decided to look for some.They figured that if you want to find a"smart gene,"you should look in smart kids.They therefore examined the DNA of students like those who are so bright that they take college entrance exams four years ear-ly-and still score at Princeton-caliber levels. The scientists found what they sought."We have,"says Plomin,"the first specific gene ever associated with general intelligence."Plomin's colleagues drew blood from two groups of 51 children each,all 6 to 15 years old and living in six counties around Cleveland.In one group,the average IQ is 103.All the children are white .Isolating the blood cells,the researchers then examined each child's chromosome 6 .Of the37 landmarks on chromosome 6 that the researchers looked for,one jumped out:a form of gene called IGF2R occurred in twice as many children in the high-IQ group as in the average group-32 percent versus 16 percent. The study,in the May issue of the journal Psychological Science, concludes that it is this form of the IGF2R gene that contributes to intelligence.Some geneticists see major problems with the IQ-gene study.One is the possibility that Plomin's group fell for"chopsticks fallacy".Geneticists might think they've found a gene for chopsticks flexibility,but all they've really found is a gene more common in Asians than,say,Af-ricans.Similarly,Plomin's IQ gene might simply be one that is more common in groups that em-phasize academic achievement."What is the gene that they've found reflects ethnicity?"asks ge-neticist Andrew Feinberg of Johns Hopkins University."That alone might explain the link to intel-ligence,since IQ tests are known for being culturally sensitive and affected by a child's environ-ment."And Neil Risch of Standford University points out that if you look for 37 genes on a chro- mosome,as the researchers did,and find that one is more common in smarter kids,that might re- flect pure chance rather than a causal link between the gene and intelligence.Warns Feinberg:"I would take these findings with a whole box of salt." Plomin's IQ-gene study is similar to the chopsticks gene finding in that______.A: there may not be a causal link between gene and intelligenceB: there is a close correlation between gene and intelligenceC: there may be a close relation between chopsticks flexibility and children's academic scoreD: there is not a close relation between chopsticks flexibility and children's academic score
MRC是什么的缩写？（）A、Modular Radio ConnectB、Modular Resistance CabinetC、Modular Radio CabinetD、Modular Resistance Connect
According to Ohm’s Law， which of the following is correct？（）A、As voltage increases， resistance decreasesB、As amperage decreases， resistance decreasesC、As resistance decreases， amperage increasesD、As resistance increases， voltage increases
单选题For practical purposes, in a simple series circuit, the source voltage will be dropped across one resistor if it has（）.Ahalf the resistance of the other resistorBa resistance equal to the otherCat least ten times the resistance of the otherDa partial short circuit
单选题If a voltmeter is connected across a line, it must be protected with a（）AshuntBhigh-resistance coil in the armature circuitClow-resistance coil in the armature circuitDshunt and a coil of high resistance
单选题Most conducting materials such as copper, aluminum, iron, nickel, and tungsten （）.Aincrease in resistance with increased temperatureBincrease in resistance with decreased temperatureCdecrease in resistance with increased temperatureDincrease in conductance with increased temperature
单选题Which of the following statements is true concerning simple parallel resistance circuits?（）AThe total current flow equals the sum of the individual currentsBThe total current flow equals the reciprocal of the sum of the individual currentsCThe total resistance equals the sum of the individual resistanceDThe total voltage equals the sum of the individual voltages across each resistance
单选题According to Ohm’s Law， which of the following is correct？（）AAs voltage increases， resistance decreasesBAs amperage decreases， resistance decreasesCAs resistance decreases， amperage increasesDAs resistance increases， voltage increases
单选题利用PubMed文献数据查找论文“Transgenic plants of Petunia hybrida harboring the CYP2E1 gene efficiently remove benzene and toluene pollutants and improve resistance to formaldehyde”的第一作者是（）。AXiangTBBaoLCLiPDZhangD
问答题在哺乳动物基因组中，如何实现stable gene repression或gene firmly shut off？