Question

Can people change their skin color without suffering like pop king Michael Jackson? Perhaps yes. Scientists have found the gene that determines skin color.

    The gene comes in two versions, one of which is found in 99 per cent of Europeans. The other is found in 93 to 100 per cent of Africans, researchers at Pennsylvania State University report in the latest issue of Science.

    Scientists have changed the color of a dark-striped zebrafish（斑馬魚） to uniform gold by inserting a version of the pigment (色素) gene into a young fish. As with humans, zebrafish skin color is determined by pigment cells, which contain melanin (黑色素). The number, size and darkness of melanin per pigment cell determine skin color.

    It appears that, like the golden zebrafish, light-skinned Europeans also have a mutation (變異) in the gene for melanin production. This results in less pigmented skin.

    However, Keith Cheng, leader of the research team, points out that the mutation is different in human and zebrafish genes.

    Humans acquired dark skin in Africa about 1.5 million years ago to protect bodies from ultra-violet rays of the sun (太陽光紫外線), which can cause skin cancer.

    But when modern humans leave Africa to live in northern latitudes, they need more sunlight on their skin to produce vitamin D. So the related gene changes, according to Cheng.

    Asians have the same version of the gene as Africans, so they probably acquired their light skin through the action of some other gene that affects skin color, said Cheng.

    The new discovery could lead to medical treatments for skin cancer. It also could lead to research into ways to change skin color without damaging it like chemical treatment did on Michael Jackson.

1.The passage mainly tells us that ________.

A. people can not change their skin color without any pain

B. the new discovery could lead to research into ways to change skin color safely

C. pop king Michael Jackson often changed his skin color as he liked

D. scientists have found out that people’s skin color is determined by the gene

2.It can be inferred from the passage that ________.

A. nowadays people who want to change their skin color have to suffer a lot from the damage caused by the chemical treatment

B. Europeans and Africans have the same gene

C. the new discovery could help to find medical treatments for skin cancer

D. there are two kinds of genes

3.Scientists have done an experiment on a dark-striped zebrafish in order to ________.

A. find the different genes of humans’

B. prove the humans’ skin color is determined by the pigment gene

C. find out the reason why the Africans’ skin color is dark

D. find out the ways of changing people’s skin color

4.The reason why Europeans are light-skinned is probably that _____

A. they are born light-skinned people

B. light-skinned Europeans have mutation in the gene for melanin production

C. they have fewer activities outside

D. they pay much attention to protecting their skin

5.The writer’s attitude towards the discovery is ________.

A. neutral B. negative        C. positive       D. unconcerned

 

Answer 1

【答案】

 

1.D

2.A

3.B

4.B

5.C

【解析】本文主要講述基因決定人的膚色。將來人們想換膚色可能不需要象邁克杰克遜那樣受罪了。

1.主旨大意題 根據全文講述的主要內容得知：科學家們發(fā)現人的膚色是由基因決定的。選D

2.A 推理判斷題 從文章最后一句話It also could lead to research into ways to change skin color without damaging it like chemical treatment did on Michael Jackson.得知，人們改變膚色會象邁克爾·杰克遜那樣受到化學藥品對皮膚的傷害。選A。

3.細節(jié)理解題 根據第三段的句子：As with humans, zebrafish skin color is determined by pigment cells, which contain melanin (黑色素).得知，因為斑馬魚和人類一樣膚色中含有黑色素，所以科學家們以此來證明之。選B

4.推理判斷題 根據第四段的句子：light-skinned Europeans also have a mutation (變異) in the gene for melanin production. This results in less pigmented skin.得知，因為歐洲人體內黑色素的基因發(fā)生了變異，所以他們的皮膚為淺膚色。選B。

5.推理判斷題 根據作者對基因決定人的膚色的論述以及文章首尾段可知，作者對此的態(tài)度是肯定的。選C

考點：考查科普類短文