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1、Unit Six,Is It in the Genes?By Arthur Allen,Questions,1.Do you agree that human behavior is predetermined by genes?Why or why not?2.What can affect a particular genes potential according to the article?3.What are fraternal and identical twins respectively?What are their similarities and differences?
2、,Text,In 1993,a National Cancer Institute researcher named Dean Hamer made what seemed to be an astonishing discovery about the genetics of human behavior.He had located a link to male homosexuality on the X chromosome,Hamer reported in Science.The story was splashed across front pages around the co
3、untry.At last,overly doting mothers and early cross-dressing games were off the hook and the predilections of everyone from Walt Whitman to Liberace could be explained by a few errant proteins.Hamers article,based on an examination of the DNA of 40 gay brothers,led to mass-market book deals and mino
4、r celebrity.There is only one small,under reported glitch:Hamers results have never been replicated.Two subsequent studies showed much weaker evidence of a gay gene;a third,published on April 23 but overshadowed by the massacre at Littleton the day before,found no evidence at all.“There is no hint o
5、r trend in the direction of the initial observation,”George Ebers,a Canadian investigator involved in the study,said in Science.,mass-market n.,adj,销售量大（的），畅销（的）vt,大量销售er n.,A quick trawl through the headlines of the 1990s finds a similar fate for other front-page genetic breakthroughs.Despite much-
6、publicized discoveries of genes for schizophrenia,manic-depression,alcoholism and bipolar disorder,the precise genetic component of these illnesses continue to elude science.The same goes for personality traits.The much-trumpeted discovery of a“novelty-seeking gene”in 1996 hasnt been replicatednor h
7、ave various“depression genes”.This is not to say that progress isnt being made in parsing the biological components of behavior.But in any given person,the interplay of genes and the environment is a horrendously complex story.Individual genes produce quite subtle effects,and the more we learn about
8、 DNA,the clearer it is that any particular genes potential can be shut down or enhanced by complex biochemical pathways contingent upon things like sleep,nutrition and stress.,Bipolar:adj.电双极的；两极地区的Bipolar disorder depression 医（状态与抑郁状态交替的）躁郁症（(亦作manic-depressive illness),A decade ago the field of be
9、havior genetics was aflutter with the hope that molecular biology would home in on what makes each of us tick.But“the fog is lifting very slowly,”says Kenneth Kender,a professor of psychiatric genetics at Virginia Commonwealth University in Richmond.“Weve learned that in psychiatric disorders,there
10、are no single genes of really large effect.If there were,wed have found them already.”Genes for certain conditions,such as Huntingtons or sickle cell disease,are known as simple Mendelian traits because they follow the straightforward model of inheritance noted by the Austrian monk Gregor Mendel las
11、t century.“Mendelian traits are like a trumpet call.The genetic signal blasts right through,”says Kender.“But the genetic effects in most behavioral disorders and traits are like whispers in a busy train station.Its hard to distinguish them from the background noise.”,home in on(靠信号、雷达等)导向目标追踪home i
12、ndustry 本国工业;手工业生产;家庭工业home instruction 家庭辅导home landscape 家庭园景Home in on sth:to aim or move exactly towards sth.对准某物,朝某物移动.,That behavior is a tricky business to predict was elegantly demonstrated by another study published in Science this month.A group of researchers at three universities-in Orego
13、n,upstate New York and Edmonton,Alberta-ran a set of identical experiments on eight different mouse strains,each bred to show distinct behavioral attributes.The idea was to see whether they would act according to type.They didnt.In some tests,genetically identical mice acted differently depended on
14、the lab that tested them.A strain of mice lacking a receptor for the neurotransmitter serotonin-a substance whose imbalance has been implicated in various addictions and mood disorders-was expected to drink more alcohol and show more anxiety than the other mice strains.But all three teams found that
15、 the serotonin-mutants didnt booze it up any more than the others.And all strains of mice tested in Alberta,it turned out,were mellower than the New York and Oregon mice.Must be the weather,eh?,Genetic programming,in other words,isnt nearly as efficient as scientists might hope.Peter W.Nathanielsz,a
16、 Cornell University obstetrician whose research focuses on the fetal environments of sheep,writes in a new book that some of the most significant programming of human health-and behavior,potentially-occurs in the womb.This isnt exactly a new observation,but advances in neuroscience highlight the fac
17、t that the migration of neurons to the precise area of the brain where they belong during pregnancy is a dicey business that can be easily disrupted.Even in a healthy pregnancy,chance has a large impact on the prenatal formation of the brain.Even twins with identical sets of genes have brains that l
18、ook different.,What happens in the womb is one of the new frontiers of the nature-nurture debate.Epidemiology has already shown how important the womb can be.Over the past several decades,David Barker of Southampton University and other researchers have been studying the outcome of the thousands of
19、Dutch babies conceived or carried during the hunger winter of 19441945,when the Nazis kept food from reaching people in Amsterdam and the surrounding area to punish the Dutch for the allied“Bridge Too Far”invasion.Immediately after the war,this population s nutrition returned more or less to normal,
20、but 50 years after their births,hunger winter babies have much higher rates of diseases like diabetes than controls.Scientists attribute the higher diabetes rates to the“thrifty fetus”phenomenon-the fetus pancreases were programmed in the womb to process much lower levels of glucose than became avai
21、lable after birth.“Babies who prepare in the womb for a thrifty existence after birth pay the price if they live a life of over-consumption in a situation in which food is plentiful,”writes Nathanielsz,who has observed the same phenomenon in animal experiments.,Rats whose mothers eat low-protein die
22、ts suffer from various behavioral and learning problems.If the rats are female,they often pass these traits on to their offspring,even if the second-generation mothers diet is normal,Nathanielsz writes in his book Life in the Womb:the Origin of Health and Disease.Malnourished rats take many generati
23、ons of healthy eating to return to normal,in a kind of Lamarckian pattern of inheritance,he writes.“The environment of the womb is of extreme importance in building the body and the brain,”Nathanielsz says.“If things go wrong there can be a permanent price to pay.”,sufferer n.受苦难者;受害者;患者,病人suffer fo
24、r 为.而受苦suffer from 患.病;受.苦suffer from cold and hunger 饥寒交迫,Twin studies,which compare the sharing of traits in fraternal and identical twins,have provided pretty convincing evidence of a genetic component to most aspects of behavior.They show in study after study that genetically identical twins,eve
25、n when separated for much of their lives,are far more similar than fraternal twins in everything from IQ to heart disease to shyness.Twin studies produce statistical estimates of the genetic contribution traitsfor example,that IQ is 50 to 80 percent genetic.But even identical twins can have remarkab
26、ly different womb environments.About a third of all identical twins are nourished with separate placentas,and in as many as 10 percent of the twins who share a placenta,one twin essentially steals womb nutrients from the other,a process that has been called“runting.”A few studies that compared the c
27、ongruence of the behavior of identical twins nurtured in different types of womb environments found“significant personality and IQ differences,”says Kendler.Pondering how these studies of womb environment could skew behavior genetics studies,Kendler admits,“is enough to make someone like me nervous.
28、”,New Words and Phraseshomosexuality 7hEumEu5seksjuEl 5Aliti n.同性恋chromosome 5krEumEsEum n.染色体doting 5dEutiNadj.沉溺于爱的，溺爱的predilection 7pri:di5lekFEn n.爱好,偏袒Walt Whitman瓦尔特惠特曼(18191892)美国历史上最伟大的诗人之一，有同性恋倾向Liberace李柏瑞斯（1919-1987）美国同性恋钢琴大师errant 5erEnt adj.偏离正道的;漂泊的protein 5prEuti:n n.蛋白质DNA(deoxyribon
29、ucleic acid)脱氧核糖核酸aflutter E5flQtE adj.飘扬的;激动的celebrity si5lebriti n.名声,名人glitch litF n.失灵，小故障replicate 5replikit v.复制,Littleton massacre 1999年4月两名学生持抢在美国科罗拉多州利特尔顿(Littleton,Colorado)的科伦拜中学(Columbine High School)杀死12名学生和一名教师后自杀。trawl trC:l n.拖网；搜罗schizophrenia skIzE5fri:nIE n.精神分裂症manic5mAnIk adj.狂躁
30、的alcoholism 5AlkEhClizEm n.酗酒elude i5lju:d,i5lu:d vt.逃脱parse pB:z vt.剖析horrendously hC5rendEs adv.惊人地contingent kEn5tindVEnt adj.依条件而定的nutrition nju:5triFEn n.营养,营养学psychiatric saiki5Atrik adj.精神病学的Huntingtons disease亨廷顿氏症：主要由大脑基底神经中枢失去部分脑细胞引起，脑细胞损伤影响患者的认知能力、行为及情绪，患者常表现为不自觉地手舞足蹈，因此1872年被亨廷顿（George H
31、untington）医生称之为“亨廷顿舞蹈症”sickle cell disease镰形细胞病Mendelian men5di:ljEn adj.(奥地利遗传学家)孟德尔的,inheritance in5heritEns n.遗传upstate 5Qp5steit adj.北部的strain strein n.血统neurotransmitter 7njuErEtrAns5mitE n.神经传递素serotonin 7siErE5tEunin n.含于血液中的复合胺mutant 5mju:tEnt n.突变体booze up 纵酒狂欢 mellow 5melEu adj.成熟的，老练的obst
32、etrician 7Cbste5triFEn n.产科医师fetal 5fi:tl adj.胎儿的neuron 5njuErCn n.神经元，神经细胞dicey 5daisi adj.不确定的，无法预言的prenatal 5pri:5neitl adj.出生以前的nurture5nE:tFE n.培育,epidemiology 7epi7di:mi5ClEdVi n.流行病学Amsterdam 5AmstE5dAm n.阿姆斯特丹(荷兰首都)diabetes 7daiE5bi:ti:z n.糖尿病，多尿症thrifty 5Wrifti adj.节约的pancreas 5pAnkrIEs n.胰
33、腺glucose 5lu:kEus n.葡萄糖malnourished mAl5nQriFt adj.营养不良的Lamarck lEmB:k 拉马克(1744-1829)法国博物学家,进化论者fraternal frE5tE:nl adj.异卵双生的placentas plE5sentE n.胎盘，胎座runt rQnt n.发育不全的矮小动物，矮子congruence kCNruEns n.一致，叠合，全等skew skju:vt.歪曲，曲解,ExercisesII.Choose the best word from the list given for each blank.Use eac
34、h word once only and make changes where necessary.aflutter hook dicey fraternal overshadow splash replicate contingent skew ponder psychiatric predilection1.When I asked his advice,he _ the matter and then told me to try again.answer:pondered 2.As it was the first time for me to fail the exam,Mother
35、 let me off the _ with a mild reprimand.answer:hook 3.The woods were _ with birds.answer:aflutter 4.A person who suddenly begins to steal may be in need of_ treatment.answer:psychiatric,5.I admit that my point of view on these things are certainly_ by my own temperament and experience.answer:skewed
36、6.The novel describes an extremely _ future on a brave new world of liquid nitrogen,tar,and smog.answer:dicey 7.Cold and hungry,we had to_ our way through the mud before sunset.answer:splash 8.The party sends its_ greetings to the trade union meeting.answer:fraternal 9.Whether or not we arrive on ti
37、me is _ on the weather.answer:contingent 10.Their gaieties were _ by the sad news.answer:overshadowed,11.We asked the artist to_ the portrait,so that we both could have a copy.answer:replicate 12.Nowadays,more and more young people have a _ for dangerous sports.answer:predilection III.Word Building
38、The affix en can be used as both prefix and suffix.The prefix en-or em-(before p or b)chiefly combines with nouns to form verbs,which means to put into,or to provide with.e.g.empower to give someone the power or lawful right.enmesh to catch if or as if in a net enrapture to fill(sb.)with great delig
39、ht or joy.ennobleto make/become nobleThe suffix en combines with adjectives to form verbs.e.g.blackento make black,deepento make deep or deeper hardento make hard or harder enslaveto make/become a slave ripento make ripe or to grow or become ripe saddento make/become sad hasten to make/become quick
40、or faster Choose an appropriate word from the above words with en/m to complete the following sentences.Change the form if necessary.He at the memory of his beloved wife.answer:saddened 2.The audience was by the freshness of the voices and the excellent orchestration.answer:enraptured 3.He was in a
41、web of deceit and lies.answer:enmeshed,4.In a strange way she seemed by the grief she had experienced.answer:ennobled 5.The water after the dam was built.answer:deepened 6.French law the police to search any suspicious person.answer:empowers 7.He was by the policemans rough treatment of his wife.ans
42、wer:enraged 8.There is a danger of patients becoming to painkilling drugs.answer:enslaved 9.The apples are quickly;we shall soon be able to pick them.answer:ripening 10.Her mind as she became used to difficulty and she became impatient of weaker people.answer:hardened,11.As the time for the guests a
43、rrival approached,the housewife her dinner preparations.answer:hastened IV.Translate the following into English.全球艾滋病的蔓延无论是在发达国家还是在发展中国家都是对医学进步的重大挑战。在过去的40年中，通过改善基本医疗保健、食品、卫生和免疫等项目，人类在控制流行病方面取得了巨大的进步，并且朝着实现“2000年人人享受健康”（世界卫生组织的一项主要目标）迈出了一大步。然而，由于艾滋病的突然降临和迅速蔓延，有可能使得这一进步化为乌有。到1988年底，共报道了13万多例艾滋病，但由于报道
44、不全，实际数量可能超过35万例。此外，至少有500万人可能携带导致艾滋病发作的艾滋病病毒。这就意味着在之后几年里会有多达40万个新的艾滋病病例这是目前艾滋病病例的两倍多。照顾艾滋病病人会给经济资源带来沉重的压力，即使在富国也是如此。,answer,V.Translate the following into Chinese.Sex determination is controlled by two chromosomes called sex chromosomes.The sex chromosomes are not homologous in the same way that the
45、 23 other autosomal chromosomes are.Male and female sex chromosomes are different in shape and contain different genes for most of their length.Only a short segment of both chromosomes seems to be homologous and carries allelic genes.Careful analysis of this theory indicates that the X chromosome ma
46、y not contain sex-determining genes for femaleness.They could occur on any chromosome.Sex-determining genes must,however,occur on the Y chromosome,for it is solely responsible for the difference between girls and boys.Therefore,the X chromosome is free to carry many genes which have nothing to do wi
47、th sex,particularly since the X chromosome occurs in both sexes.By its very nature,then,the Y chromosome is less free to carry any genes not directly related to sex,except on the short segment that is homologous with the X chromosome.,answer,The rise of Acquired Immune Deficiency Syndrome(AIDS)aroun
48、d the earth has represented a major challenge to medical progress both in developed and in the less-developed countries.The past forty years saw great success in the control of spreading diseases and great strides toward achieving“health for all by the year 2000”(a major WHO goal)through improved ba
49、sic health care,food,cleanliness,and immunization program.Yet,because of its sudden start and rapid spread,AIDS could soon wipe out this progress.By the end of 1988,more than 130,000 cases of AIDS were reported,but,because of underreporting,there may actually be more than 350,000 cases.Also,at least
50、 five million persons likely have the Human Immunodeficiency Virus(HIV),which causes AIDS.That means as many as 400,000 new cases of AIDS could occur in the next few yearsmore than doubling the present total.Caring for AIDS patients could seriously stress economic resources even in richer countries.
