Question

Can people change their skin colour without suffering like pop king Michael Jackson? Perhaps yes. Scientists have found the gene that determines skin colour. 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 colour of a dark-striped zebra fish to uniform gold by inserting a version of the pigment (色素) gene into a young fish. As with humans, zebra fish skin colour is determined by pigment cells, which contain melanosomes (黑色素体). The number, size and darkness of melanosomes per pigment cell determines skin colour.

It appears that, like the golden zebra fish, light-skinned Europeans also have a mutation (突变)in the gene for melanosome 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 zebra fish genes.

Humans acquired dark skin in Africa about 1.5 million years ago to protect bodies from ultra-violet rays of the sun, 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 colours, said Cheng.

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

56. According to the passage, scientists have found          .

A. people living in northern latitudes need more sunlight

B. the reason why people change their skin colour

C. the reason why people get skin cancer

D. the gene that determines skin colour

57. We can infer from the passage that         .

A. people like to change their skin colour

B. a mutation in the gene for melanosome production is different in human and zebra fish gene

C. people will be able to change their skin colour without chemical treatment in the future

D. skin cancer can be cured now

58. Which of the following is NOT mentioned according to the passage?

A. The version of the pigment gene of Asians and that of Africans are the same.

B. Scientists have succeeded in turning the colour of a dark-striped zebra fish into uniform gold.

C. Dark skin can protect bodies from utral-violet rays of the sun.

D. People like pop king Michael Jackson.

59. The passage is probably taken from __________.

A. a novel           B. a science report        C. a story book      D. a science fiction

Answer 1

 DCDB