We redheads are well known for our bad tempers. Now it seems there is scientific backing for our particular complaining as well.
Scientists in the United States studied a group of 144 dental patients almost half of whom had red hair. They found that the red-haired group were more sensitive to pain and as a result were twice as likely to avoid visiting the dentist.
Previous research had shown that redheads were more resistant to the effects of local anaesthesia(局部麻醉) than people with other hair colours.
The scientists say that this red-haired sensitivity to pain stems from the actions of a gene called MC1R. This is responsible for the production of melanin which gives skin and hair its colour. In about five percent of white people the gene is mutated(突变) leading to fair skin and red hair.
Researchers say there are some people with the gene in the brain and that this could affect pain sensitivity.
Professor Daniel Sessler from the Cleveland Clinic in the United States is one of the authors of the study. He says the research is a considerable scientific breakthrough.
"Red hair is the first phenotype(表现某一显性特征之生物个体或群体) of anaesthetic requirement in humans. And what I mean by phenotype is an external(外部的) characteristic.
"So suppuse you are walking down the street and you see someone who's a little older and a little younger - that tells you nothing about their anaesthetic requirement. You see a man and a woman - that tells you nothing about their anaesthetic requirement. But you see a redhead - aha! You know that person is going to require 20 percent more general anaesthesia."
From my own personal experience I would say that there is some merit to this idea. I have found that I have had to ask dentists for extra anaesthetic in the middle of procedures.
Some dentists argue that a greater sensitivity to pain might actually benefit redheads and drive them to see the dentist more quickly. In my own case I can prove that is definitely not true.
49. We learn from the text that red- haired group are _______________.
A. easily influenced by the sense of pain and need more anthaethetic reqiurement
B. usually more sensitive to some painful things
C. just well-known for their good temper and strong pain sensitivity
D. good-looking with fair skin and red hair
50. What do the scientists think this red-haired sensitivity to pain results from?
A. melanin which is responsible for the production which gives skin and hair its colour.
B. the mutated gene leading to fair skin and red hair
C. some persons with this gene in the brain
D. an external characteristic of a person.
51. According to Professor Daniel Sessler, the most amazing thing about the anaesthetic requirement in humans which can be judged by ______.
A. someone’s age and hair    
B. someome’s gender and figure
C. someone’s teeth and the skills of the dentist
D. someone’s external charateristic
52. We can infer from the last two paragraphs that _____.
A . redheads need less anaesthetic in the operation
B. the results of this red-haired sensitivity to pain will be the same
C. the writer is a red-haired person
D. redheads have many benefits of being red-haired