It's hair-raising news for criminals on the run. Scientists behind a new study have worked out how to identify individuals only based on the proteins(蛋白质) in a single strand of their hair.
While the police already look at DNA from hair as part of investigations, the technique is far from ideal: DNA is easily degradable, meaning it can only be analyzed within a certain time period after the crime. But the new technique could even be used to solve historical or archaeological cases, making it far superior to DNA sequencing in many ways.
DNA degradation depends on several environmental factors including temperature, humidity and PH. It is also affected by the activity of bacteria and other microorganisms. In contrast, actual hairs can survive for a long time—–sometimes centuries. After bones and teeth, hair is in fact one of the most resistant structures of the human body.
In order to understand how the protein can be used to identify individuals, it is important to understand mat proteins are coded by DNA.This means that a certain level of the genetic variation that we see in different people's DNA passes into their proteins. In fact, genetic information in the DNA is translated into amino-acid chains that make up proteins.
The method not only allows for human identification but it can also reveal how old the sample is and what region it comes from, so that we can distinguish between current and ancient samples. But while the discovery is exciting, the technique is not quite polished enough to be used in the court room. The main task now will be to analyze hair samples from all over the world, which will make it a lot more reliable.
The new discovery will boost the significance of hair as evidence in courts, at a time when some forensic(司法鉴定的) disciplines have been criticized in the US. It will also be of great use in archaeology.
1.What's the main idea of the passage?
A.DNA evidence is far from ideal.
B.Criminals on the run get hair-raising news.
C.Scientists are planning a test of human hair.
D.Humans can be identified by proteins in hair.
2.Which evidence is more reliable for the police to identify a criminal?
A.Lost teeth. B.The footprint.
C.Personal belongings. D.Damaged DNA.
3.In what way is the new technique superior to DNA test?
A.Serving as evidence in courts.
B.Possessing genetic information.
C.Inferring the height of a person.
D.Distinguishing the region of a person.
4.What will scientists do in the following few years?
A.Test hair samples worldwide. B.Legalize the hair evidence.
C.Apply protein-test to archaeology. D.Map the structure of DNA.
5.Who will welcome the discovery?