Skinny Genes

苗条基因

燕山大学 刘立军 供稿

TRANSCRIPT

This is Scientific American's 60-second Science. I'm Karen Hopkin.

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 svelte. And researchers have just identified one that appears to tell the body's adipose 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 trim 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...

"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 genome center in Estonia for its most slender registrants. And they weeded out people who were listed as having anorexia or other conditions that alter body fat. Then they looked for genetic markers 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 form has been associated with human cancers.

"But its normal function had never been established."

So the scientists made mutant fruit flies and mutant mice...

"To really show that the gene associated with thinness in humans makes also flies and mice skinny. And that's exactly what we found."

But the mutant gene doesn't cause the animals to eat less.

"We found that ALK acts in our brains and what it does: it allows our body to burn more calories per same food we eat."

So the brain tells fat cells to burn more of the fat they have socked away.

"People, mice and, we believe, also flies stay skinny. So this mechanism is evolutionarily conserved from insects to humans and, we do believe, opens up an entirely new field of thinness."

The study is in the journal Cell.

There are already drugs that inhibit 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."

Thanks for listening for Scientific American's 60-second Science. I'm Karen Hopkin.

VOCABULARY

1. svelte adj. (of a person, especially a woman 人，尤指女子) thin and attractive 苗条的；身材修长的

2. adipose adj. (of body tissue 身体组织) used for storing fat 用于贮存脂肪的

3. metabolism n. 新陈代谢

4. genome n. the complete set of genes in a cell or living thing 基因组；染色体组。例如：the human genome 人体基因组

5. weed out : 清除

6. anorexia n. an emotional disorder , especially affecting young women, in which there is an abnormal fear of being fat, causing the person to stop eating, leading to dangerous weight loss （尤指年轻女子害怕肥胖而引起的）厌食，食欲缺乏，神经性厌食

7. anaplastic lymphoma kinase 间变性淋巴瘤激酶

8. mutant adj. 因基因变异而不同的

9. sock away : (North Amercian English) to save money 储存（钱）；积攒（钱）

10. inhibit v. to prevent sth. from happening or make it happen more slowly or less frequently than normal 阻止；阻碍；抑制

QUESTIONS

Read the statements. Then listen to the news and decide whether the statements are true (T) or false (F).

1. Genes are factors found in folks who are naturally thin and attractive.

2. Josef Penninger is a geneticist at the University of Columbia.

3. Penninger and his colleagues started out by searching a database maintained by a genome center in Estonia for its most slender registrants.

4. ALK is a stretch of DNA whose mutant form has been associated with human cancers.

5. ALK will not allow our body to burn more calories per same food we eat.

6. Maybe one day we can indeed develop a pill which keeps us live long.

KEY

Read the statements. Then listen to the news and decide whether the statements are true (T) or false (F).

(T) 1. Genes are factors found in folks who are naturally thin and attractive.

(F) 2. Josef Penninger is a geneticist at the University of Columbia. （正确表达）Josef Penninger is a geneticist at the University of British Columbia.

(T) 3. Penninger and his colleagues started out by searching a database maintained by a genome

center in Estonia for its most slender registrants.

(T) 4. ALK is a stretch of DNA whose mutant form has been associated with human cancers.

(F) 5. ALK will not allow our body to burn more calories per same food we eat.（正确表达） ALK allows our body to burn more calories per same food we eat.

(F) 6. Maybe one day we can indeed develop a pill which helps us live long.（正确表达）Maybe one day we can indeed develop a pill which keeps us thin.

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