Book 3 Unit 8中英对照

Twins, Genes, and Environment

基因、环境与双胞胎

[1] Heredity or environment: which is stronger? The potentials which a person is born with determine in some way what he will do in life. Therefore heredity is fate, a kind of predestination. However, genes do not work in a vacuum; as soon as we begin considering the role that they play in the development of the individual, we see that there can be no development without the interacting environment. No characteristic is caused exclusively by either environment or genes. 遗传与环境究竟哪一个影响更大呢?从某种程度上讲,一个人生来具有的潜力将决定他一生的作为。因此遗传即命运,是命中注定的东西。然而,基因并不是在真空中发挥作用的;一旦我们开始认识到基因在个人发展中所起的作用,我们就会明白,没有与其相互作用的环境,就不可能有任何个人的发展。没有一个特点是完全由环境或者完全由基因造成的。
[2] The relative effects of heredity and environment are most clearly observable in identical twins. Most identical twins are raised together and are remarkably alike in both appearance and behavior. These cases demonstrate that individuals with the same genes, when raised in the same environment, will respond to it in much the same way. They do not indicate what would happen if these identical individuals were raised separately. 遗传和环境的相对影响在同卵双胞胎中最易观察到。大多数的同卵双胞胎是在一起抚养长大的,因而无论在外表还是行为上都惊人地相像。这些实例证明,若在同样的环境中抚养成长,具有相同基因的个体就会以几乎同样的方式对环境作出反应。但这些例子并不能说明如果把这些同卵双胞胎分开抚养会发生什么情况。
[3] A number of studies have been made of identical twins raised apart. The twins who were the subjects of these studies lived in America, were raised in much the same physical environments, and experienced much the same nutritional histories. Therefore, as one might expect, they maintained the closest resemblance to each other in physical appearance, height, and weight. Exceptions occurred when one twin had developed a rather severe illness and the other had not; but on the whole everyone is impressed by the great psychological and physical likenesses that exist between identical twins, even those who have been separated from infancy. 对分开抚养的同卵双胞胎已进行了许多研究。被研究的这些双胞胎都生活在美国,成长的自然环境几乎相同,并且具有几乎相同的营养史。因而,正如所料,他们在外表、身高和体重上极其相似。但也有例外:一对双胞胎中的一个患了相当严重的疾病而另一个却没生病;但是总体而言,同卵双胞胎,甚至从婴儿时就分离的同卵双胞胎,在心理和身体上会如此相似,给每个人留下了深刻的印象。
[4] In a study of nineteen sets of twins who had been separated from birth, investigators found that in approximately two thirds of the sets there were no more significant differences than existed among unseparated pairs of twins. This strongly suggests the power of the genes and the limitation of the effect of environment. However, it must be remembered that, although the identical twins who were studied lived in different families far removed from each other, the environments in those families were not, on the whole, substantially different. Usually every effort would be made to put each child in a home with a background similar to that of its own family, and therefore it should not be surprising to find that the twins developed similarly. But in those cases in which there had been a greater difference in the environments of the separated twins, the differences between the twins were more substantial. The following case illustrates what happens to identical twins when they are brought up in contrasting environments. 在对从一出生就分离的19对双胞胎的研究中,研究者发现,其中约三分之二的双胞胎之间的差异与一起长大的双胞胎之间的差异一样不明显。这有力地说明了基因的影响力和环境作用的局限性。然而,必须记住的是,尽管被研究的同卵双胞胎生活在不同家庭里且相距甚远,但总体而言,那些家庭的环境基本上没有什么差异。人们通常都会千方百计地将每个孩子安置在和他自己原来的家庭背景相同的家庭里,因而发现这些双胞胎成长中有不少相似之处就不足为奇了。但是在那些分开抚养的双胞胎的生长环境有较大差异的实例中,双胞胎之间的差异就很大。下面的例子说明了在对比度很大的环境中成长的同卵双胞胎的情况。
[5] Gladys and Helen were born in a small Ohio town and were separated at about eighteen months of age. They did not meet again until they were twenty-eight years old. Helen had been adopted twice. Her first foster parents had proved to be unstable, and Helen had been returned to the orphanage after a couple of years; after several months she was again adopted, by a farmer and his wife who lived in southeastern Michigan. This was her home for the next twenty-five years. Her second foster-mother, though she had had few educational advantages herself, was determined that Helen should receive a good education; Helen eventually graduated from college, taught school for twelve years, married at twenty-six, and had a daughter. 格拉迪丝和海伦出生于俄亥俄州的一个小镇,在大约十八个月大时被分开抚养。她们直到28岁才再次相遇。海伦被领养了两次。由于她最初的养父母靠不住,两年后海伦又被送回到孤儿院。过了几个月,她再一次被住在密歇根东南部的一对农场主夫妇领养。此后25年她一直住在那里。她的第二个养母尽管本身没受过什么教育,却下决心要让海伦得到良好的教育;海伦最终大学毕业,教了12年的书,26岁时结婚,并有了一个女儿。
[6] Gladys was adopted by a Canadian railroad conductor and his wife. When she was in the third grade, the family moved to a rather isolated part of the Canadian Rockies, where there were no schools, and Gladys' formal education came to an end, and was not resumed until the family moved to Ontario. She stayed at home and did housework until she was seventeen, and then went to work in a knitting mill. She went to Detroit at nineteen, got a job, and married when she was twenty-one. 格拉迪丝被加拿大的一个列车乘务员及其妻子领养。她读三年级的那一年,全家搬到了加拿大落基山脉一带一个相当偏僻的地方,那儿没有学校,格拉迪丝的正式教育也就此结束,直到全家搬到安大略省后才得以继续。于是格拉迪丝就呆在家里干家务,一直到她17岁,随后在一家针织厂工作。19岁那年她去了底特律,找到一份工作,21岁时结了婚。
[7] Helen had been healthier than Gladys, in childhood and adulthood, but other than that, their environments had been very similar except for their education. Their weight, height, hair color, and teeth were very similar. The differences that distinguished them were obviously associated with the different social lives they had led. 海伦在儿童和成年时期都一直比格拉迪丝健康,但除了这一点以及各自所受的教育不同之外,她们的生活环境十分相似。她们的体重、身高、发色和牙齿都十分相似。她们之间的区别显然与她们各自的社交生活不同有关。
[8] Helen was confident, graceful, made the most of her personal appearance, and showed considerable polish and ease in social relationships. Gladys was shy, self-conscious, quiet and without charming or graceful manners. A scientist who studied them remarked, "As an advertisement for a college education the contrast between these two twins should be quite effective." 海伦自信、举止得体、充分利用了她外表的优势,在社交中也显得很从容、有修养。格拉迪丝则害羞、忸怩,沉默寡言,缺乏迷人或优雅的风度。一位研究她们的科学家曾经说过:“这两个双胞胎之间的悬殊差异真可谓是大学教育的颇有说服力的广告。”
[9] Considering the nature of their environmental experiences, the differences in Helen and Gladys are not surprising. Since psychological traits depend so much upon experience, it is to be expected that they will reflect it. On the other hand, traits that are not liable to be influenced by the environment are more likely to exhibit a high degree of similarity in identical twins. Important as they are, genes alone are never absolutely responsible for any trait. What we can do is set by the genes, but what we actually do is largely determined by the environment. ( 823 words) 考虑到她们在环境方面的经历的本质不同,海伦和格拉迪丝之间的差异也就不足为怪了。由于心理特点在很大程度上取决于经历,可想而知心理特点也反映经历。另一方面,那些不易受环境影响的特点更有可能在同卵双胞胎中表现出高度的相似性。尽管基因十分重要,但是基因本身决不能完全决定任何一个特点。我们的能力会达到什么程度由基因注定,而我们真正做了什么则主要由环境决定。

 

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