2015年考研暑假必读文章:Is Snuppy the Puppy for Real?

来源:网络 2019-01-15

Is Snuppy the Puppy for Real?

With Hwang's scientific credibility in shambles, the status of the world's most famous dog hangs in the balance. The embattled scientist maintains that Snuppy is the world's first canine clone, and he even hired an independent Korean DNA lab, Human Pass Inc, to verify that assertion. The verdict: Human Pass CEO Seung Jae Rhee told TIME last week, "There is no dispute about these results, and so I am 100% certain on Snuppy's authenticity." But since Human Pass is in essence working for Hwang, that's hardly good enough for the investigative panel at Seoul National University, which is carrying out independent tests, or for the editors of Nature, who have ordered an investigation.

If Snuppy really was cloned from the ear cell of a 3-year-old male Afghan named Tai, it shouldn't be tough to prove, even to those outside investigators. As long as they have tissue samples from both the clone and the parent, they should be able to determine whether DNA in the nuclei of both animals' cells is identical-the first hallmark of a true clone.Ian Wilmut, the Scottish scientist who created Dolly the sheep in 1996, had to provide such samples to prove to skeptics that he had created history's first mammalian clone.

Even with the controversy raging over his stem-cell paper, Hwang could have forestalled some of the questions about Snuppy if he had offered one additional bit of confirming proof in his original paper in Nature. That piece of critical evidence comes from the animals' mitochondria, tiny energy-producing structures within each cell. While most of a mammal's DNA resides in the nucleus, there's also some in the mitochondria. (Nuclear DNA forms the animal's basic genetic blueprint; mitochondrial DNA contains instructions for making proteins involved in various metabolic functions within the cell. )

Mitochondrial DNA is passed down from the mother as gart of the egg's genetic contribution. Identical twins, for example, have the same nuclear and mitochondrial DNA,since they're produced when a single egg is fertilized and the resulting embryo splits in two.With a clone, the situation is different. Because the cloning process that Hwang says he used to create Snuppy involves two dogs-one for the nucleus and another for the egg-Snuppy's mitochondrial DNA should not match Tai's. That's what Rhee's scientists say they've found and what Hwang undoubtedly hopes the university and Nature will find as well. Final, ironclad proof of Snuppys provenance would involve showing that the dog's mitochondrial DNA matches that of his egg donor .It's not clear, however, whether that test is being done.

#p#副标题#e#
重点单词
credibility /;kredibiliti/
【文中释义】 n. 可信用,确实性,可靠
【大纲全义】 n. 可信用,确实性,可靠

balance 
【文中释义】 n.天平,平衡
【大纲全义】 v. 称,(使)平衡;权衡 n.天平; 平衡,均衡;差领,余放; 结存

maintain /men'tein/
【文中释义】 v. 坚特
【大纲全义】v. 维修,保养,维持,供养,坚持,主张,支持

verify /'verifai/
【文中释义】 v. 查证,核实
【大纲全义】 v. 证实,查证;证明

panel 
【文中释义】n. 专门问题小组
【大纲全义】 n. 面板,嵌板,座谈小组,专门问题小组 v. 嵌镶

tissue /'tisju:/
【文中释义】 n. (动、植物的)组织
【大纲全义】 n. 织物,薄娟,纸巾;(劝,位物的)组织

nuclei / 'nju:kliai/
【文中释义】 n. (nucleus的复数形式)细胞核
【大纲全义】 n. (nucleus的复数形式)核,核心,原子核;细胞核

additional
【文中释义】 adj. 附加的,另外的
【大纲全义】 adj. 额外的,附加的,另外的

nucleus 
【文中释义】 n. 细胞核
【大纲全义】 n. 核,核心,原子核;细胞核

blueprint /'blu:,print/
【文中释义】n. 蓝图
【大纲全义】n. 蓝图,设计图,计划 v. 制成蓝图,计划

超纲单词
shamble n. 满跚,摇羌 embattled adj. 陷入重围的
canine adj. 犬的,犬科的 hallmark n. 品质证明,标志
mammalian adj. 哺乳劝物的 mitochondria n. 线粒体
metabolic adj. 新陈代谢的 embryo n. 胚胎

重点段落译文
随着黄禹锡的科学信用的动摇,这个世界上最著名的狗的身份也悬而未定。这位陷人重围的科学家坚持称斯纳皮是世界上首只克隆犬,而且他甚至还租用了韩国一个独立的实验室—HumenPas,生物实验室来证实这个断言。判决是:上个星期,HwnanPass的总裁李顺杰告诉《时代周刊》:“这些结果是不具争谓的,我百分之百她肯宗斯纳方的真实性。”但是HnmanPaca实质上也是为黄禹锡工作的.这不管是对于进行独立测试的首尔大学的专家调查小组还是命令进行调查的《自然》的编辑来说都是远远不够的。

如果斯纳皮真的是从一个名叫泰的3岁的阿富汗公狗的耳朵细胞克隆出来的,这应该不难证明,即使是对那些外行的调查者来说。只要他们在克隆体和母体的组织中提取样本就能判断这两个动物细胞核里的DNA是否相同,而这是一个真正的克隆物的首要标志。在1996年创造出了克隆羊多莉的苏格兰科学家伊恩·威尔姆特就不得不提供了这样的样本来向怀疑者证明他创造了历史上首个克隆哺乳动物。

即使争议牵涉到了他的干细胞论文,如果他在《科学》里的原始论文中提供了额外的确凿证据,黄禹锡就能在斯纳皮的某些问题中抢占先机。那份决定性的证据来自于每个细胞里微小的能量制造结构—动物的线粒体。大多数哺乳动物的DNA都存储于细胞核中,也有一些在线粒体中。(细胞核中的DNA构成了动物基本的基因蓝图,线粒体中的DNA包含了制造蛋白质的指令,这些蛋白质参与细胞的各种新陈代谢功能。)

线粒体中的DNA是作为卵子遗传物的一部分从母体传递下来的。例如,孪生双胞胎有相同的细胞核DNA和线粒体DNA,因为他们的诞生是由于一个卵子受精而由此产生的胚胎分裂成两个。对克隆物来说情况就截然不同了。因为黄禹锡说他创造斯纳皮的克隆过程涉及两条狗—取一条狗的细胞核,取另一条狗的卵子—斯纳皮的线粒体DNA是不可能与泰的线粒体DNA一致的。那就是李顺杰的科学家们所说的他们已经发现的东西,无疑也是黄禹锡希望首尔大学和《自然》发现的。最终,关于斯纳皮来源的可靠证据将会显示该条狗的线粒体DNA与它的卵子捐赠者的线粒体DNA是一致的,然而,是否进行了这项测试还不是很清楚。




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