Many science fiction stories tell about explorers arriving in a new world. The explorers then use some kind of high-tech device to test for breathable air or signs of life. But here on Earth, science fiction is becoming reality through a new sampling technology called environmental DNA, or e-DNA for short. Scientists can use it to identify rare or invasive species, study bio-diversity or estimate fish populations with just a little air or water.
Ryan Kelly is an ecologist at the School of Marine and Environmental Affairs at the University of Washington in Seattle. He works in a laboratory there with other researchers. They study the genetic material released by living creatures. “Essentially we can take a sample of soil or air — and in our case — water, and we can sequence（to arrange the order of genes）the DNA out of it and tell you what is there.”
Ryan Kelly says he and his research team are studying water samples collected from Puget Sound. He says the cost of gene sequencing has “been reduced greatly in recent years.” That makes DNA testing more widely available.
Environmental DNA can be used in two ways. One is to identify the creatures that live in a certain place. The other is to confirm the presence or lack of a specific creature.
Caren Goldberg heads the new e-DNA lab at Washington State University in Pullman, Washington. She is one of the first biologists in the northwestern United States to take the technology from the testing phase to actually using it.
“It is extremely useful for species that are really hard to find. I have spent many hours looking for species that I was pretty sure were there — looking under rocks, looking in water, doing all kinds of surveys.”
Caren Goldberg sees e-DNA as a way to get answers more efficiently, safely and with less destruction compared to traditional survey techniques. Until recently, scientists depended on diving deep, netting or using an electric current to temporarily catch fish.
“We’re absolutely at this point where proof-of-concept has been established. I don't think everyone necessarily is ready for it yet, but I think the majority of people are.”
This newer way to identify what lives in the environment is becoming popular around the world. Animal experts in Vietnam are using the e-DNA to find the last, wild Yangtze giant softshell turtles. One researcher on the Caribbean island of Trinidad is using the sampling technology to find endangered golden tree-frogs. And in Madagascar, it is being used to identify amphibian diseases.
Ms. Goldberg has used e-DNA testing to confirm the local extinction, disappearance, of a leopard frog in the American state of Idaho. She has also been asked to document the spread of the New Zealand mud-snail in the state of Washington. The creature has been found in lakes and other waterways across the state.
Now, the U.S. Bureau of Land Management wants Caren Goldberg to look for the Columbia spotted frog in two other western states. The rare amphibian is a candidate for the federal government's threatened species list.
Scientists working with the technology say they do not expect robots to replace field biologists anytime soon. But the old-fashioned field work could soon be more targeted.
A related research goal is to show how long environmental DNA can last and how far it can travel in different environments.
Paragraph One is intended as _____ of the passage.

A．the main idea

B．the introduction of the topic

C．a supporting detail of the main idea

D．a contrast of the main idea

What has made E-DNA magic is that with E-DNA_____.

A．you are likely to find information about a species with a little air, water, or soil

B．some kind of high-tech device can be used to test for breathable air or signs of life

C．you are able to get answers more efficiently, safely though with more damage

D．the cost of gene sequencing has been reduced greatly in recent years.

So far, the technique of E-DNA has NOT helped scientists search for ______.

A．wild Yangtze giant soft-shell turtles

B．endangered golden tree-frogs

C．the local extinction of a leopard frog

D．the spread of the New Zealand mud-snail

Despites its advantage, we are still not sure of something about E-DNA. That is _____ .
A. the lasting time and the spreading area of E-DNA
B .the lasting time of E-DNA and too many species for E-DNA
C. too many candidates for E-DNA and the lasting time of E-DNA
D. robots and old-fashioned field work’s replacing E-DNA
The passage can be sorted as a(n) _____.

A．science fiction	B．experiment report
C．science report	D．bio-diversity discovery

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