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DNA science.

In "DNA Trackers" (p. 18), you read about two teens who hunted down DNA in New York City. Scientists are not only able to read DNA's genetic code, but they can also alter living organisms' genes in the lab. Read the passage below to learn more, and then answer the questions that follow.

Glowing Kitties

Here's a trick your cat can't do: glow in the dark. Scientists have created cats that glow bright red when they are placed under ultraviolet light, a type of light that can't be seen by humans.

To make the cats glow, South Korean scientists altered the animals' DNA. This molecule contains information about the characteristics of an organism. The scientists added a special gene, or segment of DNA, into the skin cell of a cat. The gene isn't normally found in felines--it came from a sea anemone. The gene causes anemones' skin to produce a compound that glows red in ultraviolet light.

The altered skin cell's DNA was added to the reproductive cells of a female cat. When the cat gave birth, all of her kittens contained the gene in their DNA. So the skin of each of the kittens glows in the dark.

In the future, scientists hope the same procedure could be used to create cloned animals with genes that cause human diseases. Scientists could then study the animals to better understand these illnesses, says Michigan State University animal scientist Jose Cibelli.

1. Which of the following BEST summarizes the passage above?

(A) All creatures glow under ultraviolet light, and now scientists have discovered why.

(B) A new glow-in-the-dark gene has been found in a rare breed of cats.

(C) The best new pet of the season is a high-tech glow-in-the-dark cat.

(D) Scientists have altered cats' DNA to make them glow. Someday this technology could be used to understand human diseases.

2. What is the purpose of the second paragraph?

(A) to describe the process that made the cats glow

(B) to introduce the fact that the kittens glow only in ultraviolet light

(C) to describe how the kittens were born

(D) to describe the future prospects of this type of research

3. Which type of light causes the kittens to glow?

(A) visible

(B) infrared

(C) ultraviolet

(D) X-rays

4. What is a gene?

(A) the entire code of an animal's DNA

(B) a segment of DNA

(C) a skin cell

(D) a synonym for glow

5. Which of these statements is NOT a fact from the article?

(A) Kittens that glow in ultraviolet light were born.

(B) Ultraviolet light can't be seen by humans.

(C) The kittens will glow only while they're young.

(D) Scientists altered the DNA of a cat's skin cell.

1. d 2. a 3. c 4. b 5.c

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Publication:Science World
Geographic Code:1USA
Date:Sep 27, 2010
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