高三说明文阅读 | 瘦子为什么瘦,原来是基因决定的!

分享一篇很有意思的阅读理解，武昌区2023年高三五调的阅读理解D篇，题源是来自科学美国人2021年期刊的一篇文章，高中生不妨先试做一下。

    D

    Do you have skinny genes? And I'm not talking about the pants you wore in college but can't fit into anymore. No, skinny genes are factors found in folks who are naturally thin. And researchers have just identified one that appears to tell the body's tissue to burn more fat. We all know these people who can eat whatever they want but never gain any weight.

    Josef Penninger is a geneticist at the University of British Columbia. He says that individuals who are effortlessly thin may hold the key to understanding obesity. See, scientists interested in learning how we control our weight have traditionally focused on the things that make you fat, like diet or metabolism( 新陈代谢). “But not really studied why people actually stay skinny. So we thought we'd just turn around the fields and study genetics of thinness.

    Penninger and his colleagues started out by searching a database maintained by a genomecenter in Estonia for its most thin registrants. And they weeded out people who were listed ashaving anorexia(厌食症) or other conditions that change body fat. Then they looked for geneticmarkers that track with these Skinny Petes.

    One gene, in particular, caught their eye: ALK, or the gene for anaplastic lymphoma kinase.is a stretch of DNA whose mutant(突变体) form has been associated with human cancers.“But its normal function had never been established.” So the scientists made mutant fruitflies and mutant mice. “To really show that the gene associated with thinness in humans makesalso flies and mice skinny. And that's exactly what we found But the mutant gene doesn'tcause the animals to eat less. “We found that ALK acts in our brains and what it does: it allowsour body to burn more calories per same food we eat. So the brain tells fat cells to burn more ofthe fat they have socked away.

    People, mice and, we believe, also flies stay skinny. So this mechanism is evolutionarilyconserved from insects to humans and, we believe, opens up an entirely new field of thinness.There are already drugs that prevent the cancer-causing form of ALK, which means that ALK is what scientists call a druggable target. "So maybe one day we can indeed develop a pill which keeps us thin.

32. What did the previous study focus on?

A. Skinny genes.

B. Subjects’ daily routines.

C. Family members’influence

D. Factors contributing to being fat.

33. What does the underlined phrase mean in Para. 4?

A. Included.

B. Counted.

D.Removed.

C.Compared.

34. What do we know about ALK from the passage?

A. It is a gene to burn fat.

B. It is unique to wild creatures.

C. It dominates cancer drugs.

D. It makes the carriers eat less.

35. What is the researchers’ attitude towards the new direction of the study?

A. Optimistic.

B.Conservative.

C. Doubtful.

D.Hopeless.

⋯♡⋯⋯⋯♡⋯⋯⋯♡⋯⋯⋯♡⋯⋯♡⋯⋯⋯♡⋯⋯⋯♡⋯⋯⋯♡⋯⋯♡⋯⋯⋯

全文翻译：

    你有瘦的基因吗？我说的不是你在大学时穿的那条裤子，而是你再也穿不下的那条裤子。不，"瘦基因 "是在天生瘦的人身上发现的因子。研究人员刚刚发现了一种基因，它似乎能告诉身体组织燃烧更多脂肪。我们都知道，有些人想吃什么就吃什么，但体重却从未增加。

    约瑟夫-潘宁格是不列颠哥伦比亚大学的遗传学家。他说，不费吹灰之力就能瘦下来的人可能是了解肥胖的关键。他说，那些不费吹灰之力就能瘦下来的人可能是了解肥胖症的关键所在。"但却没有真正研究过人们为什么会保持苗条身材。因此，我们想把研究领域转过来，研究瘦的遗传学。

    彭宁格和他的同事们首先搜索了爱沙尼亚一个基因组中心维护的数据库，寻找最瘦的注册者。他们剔除了那些被列为患有厌食症或其他会改变体脂状况的人。然后，他们寻找与这些 "瘦皮特人 "相关的遗传标记。

    其中一个基因尤其引起了他们的注意：ALK，即无性淋巴瘤激酶基因，是一段DNA，其突变体形式与人类癌症有关。"但它的正常功能从未被确定。于是，科学家们制造了突变果蝇和突变小鼠。"要真正证明与人类消瘦有关的基因也会使果蝇和小鼠消瘦。但突变基因并没有导致动物吃得更少。"我们发现，ALK在我们的大脑中起作用，它的作用是：让我们的身体在吃同样的食物时燃烧更多的卡路里。因此，大脑会告诉脂肪细胞燃烧更多的脂肪。

    人、小鼠，我们相信，苍蝇也会保持苗条身材。因此，这种机制从昆虫到人类都在进化中得到了保留，我们相信，它开辟了一个全新的瘦身领域。目前已经有药物可以阻止ALK的致癌形式，这意味着ALK是科学家们所说的可药物靶点。"因此，也许有一天我们真的可以研制出一种药片，让我们保持苗条身材。

⋯♡⋯⋯⋯♡⋯⋯⋯♡⋯⋯⋯♡⋯⋯♡⋯⋯⋯♡⋯⋯⋯♡⋯⋯⋯♡⋯⋯♡⋯⋯⋯

阅读理解答案如下：

Keys: DDCC