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DNA Fingerprinting？？ DNA isthe genetic material found within the cell nuclei of all living

DNA Fingerprinting

？？ DNA isthe genetic material found within the cell nuclei of all living things. Inmammals the strands of DNA are grouped into structures called chromosomes. Withthe exception of identical sib- lings (as in identical twins) , the completeDNA of each individual is unique.

？？DNAfingerprinting is somet？？imes called DNA typing. It is a method of identificationthat compares bits of DNA. A DNA fingerprint is constructed by first drawingout a DNA sample from body tissue or fluid such as hair, blood, or saliva. Thesample is then segmented using enzymes, and the segments are arranged by size.The segments are marked with probes and exposed on X-ray film, where they forma pattern of black bars-the DNA fingerprint. If the DNA fingerprints producedfrom two differ- ent samples match, the two samples probably came from the sameperson.？？

？？DNAfingerprinting was first developed as all identification technique in 1985.Originally used to detect the presence of genetic diseases, it soon came to beused in criminal investigations and legal af- fairs. The first criminal convictionbased on DNA evidence in the United States occurred in 1988. In criminalinvestigations, DNA fingerprints derived from evidence collected at the crimescene are com- pared to the DNA fingerprints of suspects. Generally, courtshave accepted the reliability of DNA tes- ting and admitted DNA test resultsinto evidence. However, DNA fingerprinting is controversial in a number ofareas:the accuracy of the results, the cost of testing, and the possible misuseof the tech-nique.

？？ Theaccuracy of DNA fingerprinting has been challenged for several reasons. First？？,because DNA seg-ments rather than complete DNA strands are"fingerprinted": a DNA fingerprint may not be unique; large-scaleresearch to confirm the uniqueness of DNA fingerprinting test results has notbeen conducted. In addi-tion, DNA fingerprinting is often done in privatelaboratories that may not follow uniform. testing standards and qualitycontrols. Also, since human beings must interpret the test, human error couldlead to false re-sults.

？？ DNA fingerprinting is expen？？sive. Suspectswho are unable to provide their own DNA to experts may not be able tosuccessfully defend themselves against charges based on DNA evidence.

？？ Widespread use of DNA testing for identification purposes may lead tothe establishment of a DNA fingerprint database？？.？？

？？ According to the essay, we can findchromosomes ________？？

A.in a fish

B.in a tree

C.in a sheep

D.in a rock

提问人：网友zjf6738 发布时间：2022-01-07
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更多“DNA Fingerprinting？？ DNA isthe…”相关的问题
第1题
阅读理解。????People smile at times. However, the m...
阅读理解。
People smile at times. However, the meaning of a smile in different cultures may be different. Depending

on different cultures, smiling can express joy and amusement, but it can also show embarrassment.

People in the United States smile a lot. Every one smiles at each other in order to show they are open and

friendly. However, in China, smiling is not only an expression of happiness, but also a way to avoid being

embarrassed. Chinese people like smiling when they are embarrassed in order to avoid embarrassment. Smiling

is a kind of good will but not sneer (嘲笑). For example: When a child falls off from a bike, the adults in China may smile, which is a kind of gentle encouragement and not a kind of impolite laugh.

When a person from the United States might blush(脸红)with embarrassment or become offensive (冒犯的), a Chinese might blush with smile. To avoid serious misunderstanding, people who engage in intercultural

communication should be able to understand the meaning of smiling properly.

1. We can use smile to express all of the following feelings except ______.
A. joy and happiness

B. amusement

C. embarrassment

D. fear

2. People often smile at each other in the United States because ______.
A. they are very happy

B. they want to show they are friendly

C. they want to hide their true feelings

D. they want to avoid embarrassment

3. In China, seeing a child falls off a bike, an adult will smile in order to ______.
A. laugh at him

B. avoid his own embarrassment

C. avoid embarrassment and encourage the boy

D. show his politeness

4. What is mainly talked about in the passage？
A. People smile at times.

B. Smiling can express different feelings depending on different cultures.

C. Americans are more open and friendly than Chinese people.

D. The Chinese people often hide their true feelings.

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第2题
以下哪种遗传标记更适合检验高度降解检材：( )

A、DNA指纹

B、VNTR

C、SNP

D、大卫星DNA

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第3题
Process of determining precise order of nucleotides within DNA is

A、DNA replication

B、denaturation

C、blotting

D、DNA sequencing

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第4题
In recombinant DNA technology a plasmid vector is cleaved by

A、Modified DNA ligase

B、A heated alkaline solution

C、The same enzyme that cleave the donor DNA

D、The different enzyme other than that cleave the donor DNA

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第5题
DNA replication results in:

A、Protein production

B、Two new daughter strands

C、Heavy DNA

D、Induced mutations

E、mRNA transcripts

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第6题
In absolute refractory period, the excitability of the cell

A、low

B、no response to stimulation

C、high

D、same with that at resting potential.

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第7题
The vaccine may be useful for treating other cancers.

A.Right

B.Wrong

C.Not mentioned

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第8题
"Don't Drink Alone" Gets New Meaning

In what may be bad news for bars and pubs, an European research group has found that people drinking alcohol outside of meals have a significantly higher risk of cancer in the mouth and neck than do those who drink with food. Luigino Dal Maso and his colleagues studied the drinking patterns of l,500 patients from four cancer studies and another 3,500 adults who had never had cancer.

After the researchers accounted for the amount of alcohol consumed, they found that individuals who downed a significant share of their alcohol outside of meals faced at least a 50 t0 80 percent risk of cancer in the oral cavity(口腔) , pharynx (咽 ) , and esophagus(食管) , when compared with people who drank only at meals. Consuming alcohol without food also increased by at least 20 percent the likelihood of laryngeal cancer(喉癌). "Roughly 95 percent of cancers at these four sites traced too smoking or drinking by study volunteers, " Dal Maso says. The discouraging news his team reports, is that drinking with meals didn't eliminate cancer risk at any of the sites.

For their new analysis, the European scientists divided people in the study into four groups,based on how many drinks they reported having in an average week. The lowest-intake group included people who averaged up t0 20 drinks a week. The highest group reported downing at least 56 cups of alcohol weekly for an average of eight or more per day. Cancer risks for the mouth and neck sites rose steadily with consumption even for people who reported drinking only with meals. For instance, com-pared with people in the lowest-consumption group, participants who drank 21 t0 34 alcohol cups a week at least doubled their cancer risk for all sites other than the larynx. If people in these consump-tion groups took some of those drinks outside meals, those in the higher consumption group at least quadrupled(四倍) their risk for oral cavity and esophageal cancers.

People in the highest-consumption group who drank only with meals had lo times the risk of oral cancer, 7 times the risk of pharyngeal cancer, and 16 times the risk of esophageal cancer compared with those who averaged 20 0r fewer drinks a week with meals. In contrast, laryngeal cancer risk the high-intake, with-meals-only group was only triple that in the low-intake consumers who drank with meals.

"Alcohol can inflame(使发炎) tissues. Over time, that inflammation can trigger cancer. " Dal Maso says. He suspects that food reduced cancer risk either by partially covering digestive-tract (消化道) tissues or by scrubbing alcohol off those tissues. He speculates that the reason laryngeal risks were dramatically lower for all study participants traces to the tissue's lower exposure to alcohol

Who are more likely to develop cancer in the mouth and neck？

A.People who drink alcohol outside of meals

B.People who drink alcohol at meals

C.People who never drink alcohol

D.People who drink alcohol only at bars and pubs

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