AteamofMichiganStateUniversity(MSU)researchershasdevelo...

习题库
关注：2.19W次

问题详情：

A team of Michigan State University(MSU) researchers has developed a new，more efficient way of cloning zebra fish，a breakthrough that could have an impact on research into human health.

Zebra fish are quickly becoming the animal of choice for many researchers.

“After mice，they are the most commonly used vertebrates，that is，animals with backbones，in genetic studies，”says Jose Cibelli，the leader of the team.“They are used in cancer and heartdisease research because they have many of the same genes as people have.”

For more than 20 years，zebra fish have also served as an excellent model for understanding both normal development and birth recently，research with zebra fish has extended to modeling human diseases.

Traditional cloning uses an egg and a donor(捐赠者) DNA is removed from the egg and replaced by the DNA taken from the resulting fish is an exact genetic copy of the Cibelli's technique，the egg is removed from the female zebra fish and placed in the ovarian(卵巢的) fluid of a Chinook salmon，another kind of fish，before the donor cell is placed into the previous methods of cloning zebra fish had very low survival the new technique，the number of cloned fish is increased by 15 percent.

What makes zebra fish so useful in research is that their eggs are transparent(透明的)，making the fish's development easy to follow.

Improving zebrafish cloning techniques is also important because currently the mouse is the only good model for genetic research.

“So far the mouse is the only animal from which you can delete genes in a reliable way，”Cibelli says.“What researchers do is mutate(使变异) a gene，destroy its function completely，and then study the consequences.”

1. What do we learn about zebra fish from the text?

A．They can be used to cure human diseases.

B．They have been used in genetic studies for 20 years.

C．They are the only vertebrates used in cloning.

D．Their survival rates are increased by the new method of cloning.

2. Researchers choose zebra fish for genetic research because ________.

A．they have the same genes as human beings

B．they are a kind of vertebrate

C．their genes can be changed

D．their eggs are easy to observe

3. We can infer the following from the text EXCEPT that ________.

A．the zebra fish cloning technology may provide a new model for genetic research