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 diff

2、erences?,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 a

3、round the country. 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 bo

4、ok deals and minor 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

5、 all. “There is no hint or trend in the direction of the initial observation,” George Ebers, a Canadian investigator involved in the study, said in Science.,mass-market n., adj, 銷售量大（的），暢銷（的） vt, 大量銷售er n.,A quick trawl through the headlines of the 1990s finds a similar fate for other front-page gen

6、etic breakthroughs. Despite much-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

7、gene” in 1996 hasnt been replicatednor have 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 qui

8、te subtle effects, and the more we learn about 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.電雙極的；兩極地區(qū)的 Bipolar disorder depression 醫(yī)（狀態(tài)與抑郁狀態(tài)交替的）躁郁癥（(亦作mani

9、c-depressive illness),A decade ago the field of behavior 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 Richm

10、ond. “Weve learned that in psychiatric disorders, there 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 mode

11、l of inheritance noted by the Austrian monk Gregor Mendel last 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 distinguis

12、h them from the background noise.”,home in on (靠信號(hào)、雷達(dá)等)導(dǎo)向目標(biāo)追蹤 home industry 本國(guó)工業(yè); 手工業(yè)生產(chǎn);家庭工業(yè) home instruction 家庭輔導(dǎo) home landscape 家庭園景 Home in on sth: to aim or move exactly towards sth. 對(duì)準(zhǔn)某物,朝某物移動(dòng).,That behavior is a tricky business to predict was elegantly demonstrated by another study published i

13、n Science this month. A group of researchers at three universities-in Oregon, 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. Th

14、ey didnt. In some tests, genetically identical mice acted differently depended on 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 alcoh

15、ol and show more anxiety than the other mice strains. But all three teams found that 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 programmi

16、ng, in other words, isnt nearly as efficient as scientists might hope. Peter W. Nathanielsz, a 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-occur

17、s in the womb. This isnt exactly a new observation, but advances in neuroscience highlight the fact 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 impa

18、ct on the prenatal formation of the brain. Even twins with identical sets of genes have brains that look 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 Ba

19、rker of Southampton University and other researchers have been studying the outcome of the thousands of 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 “Brid

20、ge Too Far” invasion. Immediately after the war, this population s nutrition returned more or less to normal, 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” ph

21、enomenon-the fetus pancreases were programmed in the womb to process much lower levels of glucose than became available 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,” w

22、rites Nathanielsz, who has observed the same phenomenon in animal experiments.,Rats whose mothers eat low-protein diets 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 norm

23、al, Nathanielsz writes in his book Life in the Womb: the Origin of Health and Disease. Malnourished rats take many generations 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

24、 and the brain,” Nathanielsz says. “ If things go wrong there can be a permanent price to pay.”,sufferer n. 受苦難者; 受害者; 患者, 病人 suffer for 為.而受苦 suffer from 患.病; 受.苦 suffer from cold and hunger 饑寒交迫,Twin studies, which compare the sharing of traits in fraternal and identical twins, have provided prett

25、y convincing evidence of a genetic component to most aspects of behavior. They show in study after study that genetically identical twins, even 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 st

26、atistical estimates of the genetic contribution traitsfor example, that IQ is 50 to 80 percent genetic. But even identical twins can have remarkably 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

27、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 congruence of the behavior of identical twins nurtured in different types of womb environments found “significant personality and IQ differences,” sa

28、ys Kendler. Pondering how these studies of womb environment could skew behavior genetics studies, Kendler admits, “is enough to make someone like me nervous.”,New Words and Phrases homosexuality 7hEumEu5seksjuEl 5Aliti n. 同性戀 chromosome 5krEumEsEum n. 染色體 doting 5dEutiNadj. 沉溺于愛的，溺愛的 predilection 7p

29、ri:di5lekFEn n. 愛好, 偏袒 Walt Whitman瓦爾特惠特曼(18191892)美國(guó)歷史上最偉大的詩(shī)人之一，有同性戀傾向 Liberace李柏瑞斯（1919-1987）美國(guó)同性戀鋼琴大師 errant 5erEnt adj. 偏離正道的; 漂泊的 protein 5prEuti:n n. 蛋白質(zhì) DNA (deoxyribonucleic acid) 脫氧核糖核酸 aflutter E5flQtE adj. 飄揚(yáng)的; 激動(dòng)的 celebrity si5lebriti n. 名聲, 名人 glitch litF n. 失靈，小故障 replicate 5replikit v

30、. 復(fù)制,Littleton massacre 1999年4月兩名學(xué)生持搶在美國(guó)科羅拉多州利特爾頓(Littleton, Colorado)的科倫拜中學(xué) (Columbine High School) 殺死12名學(xué)生和一名教師后自殺。 trawl trC:l n. 拖網(wǎng)；搜羅 schizophrenia skIzE5fri:nIE n. 精神分裂癥 manic5mAnIk adj. 狂躁的 alcoholism 5AlkEhClizEm n. 酗酒 elude i5lju:d, i5lu:d vt. 逃脫 parse pB:z vt. 剖析 horrendously hC5rendEs adv

31、. 驚人地 contingent kEn5tindVEnt adj. 依條件而定的 nutrition nju:5triFEn n. 營(yíng)養(yǎng), 營(yíng)養(yǎng)學(xué) psychiatric saiki5Atrik adj. 精神病學(xué)的 Huntingtons disease亨廷頓氏癥：主要由大腦基底神經(jīng)中樞失去部分腦細(xì)胞引起，腦細(xì)胞損傷影響患者的認(rèn)知能力、行為及情緒，患者常表現(xiàn)為不自覺地手舞足蹈，因此1872年被亨廷頓（George Huntington）醫(yī)生稱之為“亨廷頓舞蹈癥” sickle cell disease鐮形細(xì)胞病 Mendelian men5di:ljEn adj. (奧地利遺傳學(xué)家)孟德爾

32、的,inheritance in5heritEns n. 遺傳 upstate 5Qp5steit adj. 北部的 strain strein n. 血統(tǒng) neurotransmitter 7njuErEtrAns5mitE n. 神經(jīng)傳遞素 serotonin 7siErE5tEunin n. 含于血液中的復(fù)合胺 mutant 5mju:tEnt n. 突變體 booze up 縱酒狂歡 mellow 5melEu adj. 成熟的，老練的 obstetrician 7Cbste5triFEn n. 產(chǎn)科醫(yī)師 fetal 5fi:tl adj. 胎兒的 neuron 5njuErCn n.

33、 神經(jīng)元，神經(jīng)細(xì)胞 dicey 5daisi adj. 不確定的，無法預(yù)言的 prenatal 5pri:5neitl adj. 出生以前的 nurture5nE:tFE n. 培育,epidemiology 7epi7di:mi5ClEdVi n. 流行病學(xué) Amsterdam 5AmstE5dAm n. 阿姆斯特丹(荷蘭首都) diabetes 7daiE5bi:ti:z n. 糖尿病，多尿癥 thrifty 5Wrifti adj. 節(jié)約的 pancreas 5pAnkrIEs n. 胰腺 glucose 5lu:kEus n. 葡萄糖 malnourished mAl5nQriFt a

34、dj. 營(yíng)養(yǎng)不良的 Lamarck lEmB:k 拉馬克(1744-1829) 法國(guó)博物學(xué)家, 進(jìn)化論者 fraternal frE5tE:nl adj. 異卵雙生的 placentas plE5sentE n. 胎盤，胎座 runt rQnt n. 發(fā)育不全的矮小動(dòng)物，矮子 congruence kCNruEns n. 一致，疊合，全等 skew skju: vt. 歪曲，曲解,Exercises II. Choose the best word from the list given for each blank. Use each word once only and make chan

35、ges where necessary. aflutter hook dicey fraternal overshadow splash replicate contingent skew ponder psychiatric predilection 1. 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 let me off the _ with

36、 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 6. The nove

37、l 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

38、time 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

39、. Word Building 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 f

40、ill (sb.) with great delight or joy. ennobleto make/become noble The 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 sa

41、d hasten to make/become quick 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 orchestrati

42、on. answer: enraptured 3. He was in a 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

43、 by the policemans rough treatment of his wife. answer: 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 w

44、eaker people. answer: hardened,11. As the time for the guests arrival approached, the housewife her dinner preparations. answer: hastened IV. Translate the following into English. 全球艾滋病的蔓延無論是在發(fā)達(dá)國(guó)家還是在發(fā)展中國(guó)家都是對(duì)醫(yī)學(xué)進(jìn)步的重大挑戰(zhàn)。在過去的40年中，通過改善基本醫(yī)療保健、食品、衛(wèi)生和免疫等項(xiàng)目，人類在控制流行病方面取得了巨大的進(jìn)步，并且朝著實(shí)現(xiàn)“2000年人人享受健康”（世界衛(wèi)生組織的一項(xiàng)主要目

45、標(biāo)）邁出了一大步。然而，由于艾滋病的突然降臨和迅速蔓延，有可能使得這一進(jìn)步化為烏有。到1988年底，共報(bào)道了13萬(wàn)多例艾滋病，但由于報(bào)道不全，實(shí)際數(shù)量可能超過35萬(wàn)例。此外，至少有500萬(wàn)人可能攜帶導(dǎo)致艾滋病發(fā)作的艾滋病病毒。這就意味著在之后幾年里會(huì)有多達(dá)40萬(wàn)個(gè)新的艾滋病病例這是目前艾滋病病例的兩倍多。照顧艾滋病病人會(huì)給經(jīng)濟(jì)資源帶來沉重的壓力，即使在富國(guó)也是如此。,answer,V. Translate the following into Chinese. Sex determination is controlled by two chromosomes called sex chrom

46、osomes. The sex chromosomes are not homologous in the same way that the 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

47、 genes. Careful analysis of this theory indicates that the X chromosome may 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 with sex, particularly since the X chromosome occurs in both sexes. By its very nature, then, the Y chromosome is less free to carry