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Don't wash those fossils!
Standard museum practice can wash away DNA.
1.Washing, brushing and varnishing fossils — all standard conservation
treatments used by many fossil hunters and museum curators alike — vastly
reduces the chances of recovering ancient DNA.
2.Instead, excavators should be handling at least some of their bounty with
gloves, and freezing samples as they are found, dirt and all, concludes a paper
in the Proceedings of the National Academy of Sciences today.
3.Although many palaeontologists know anecdotally that this is the best way
to up the odds of extracting good DNA, Eva-Maria Geigl of the Jacques Monod
Institute in Paris, France, and her colleagues have now shown just how important
conservation practices can be.This information, they say, needs to be hammered
home among the people who are actually out in the field digging up bones.
4.Geigl and her colleagues looked at 3,200-year-old fossil bones belonging to
a single individual of an extinct cattle species, called an aurochs.The fossils
were dug up at a site in France at two different times — either in 1947, and
stored in a museum collection, or in 2004, and conserved in sterile conditions
at -20 oC.
5.The team's attempts to extract DNA from the 1947 bones all failed.The newly
excavated fossils, however, all yielded DNA.
6.Because the bones had been buried for the same amount of time, and in the
same conditions, the conservation method had to be to blame says Geigl."As much
DNA was degraded in these 57 years as in the 3,200 years before," she says.
Wash in, wash out
7.Because many palaeontologists base their work on the shape of fossils
alone, their methods of conservation are not designed to preserve DNA, Geigl
explains.
8.The biggest problem is how they are cleaned.Fossils are often washed
together on-site in a large bath, which can allow water — and contaminants in
the form of contemporary DNA — to permeate into the porous bones."Not only is
the authentic DNA getting washed out, but contamination is getting washed in,"
says Geigl.
9.Most ancient DNA specialists know this already, says Hendrik Poinar, an
evolutionary geneticist at McMaster University in Ontario, Canada.But that
doesn't mean that best practice has become widespread among those who actually
find the fossils.
10.Getting hold of fossils that have been preserved with their DNA in mind
relies on close relationships between lab-based geneticists and the excavators,
says palaeogeneticist Svante P bo of the Max Planck Institute for Evolutionary
Anthropology in Leipzig, Germany.And that only occurs in exceptional cases, he
says.
11.P bo's team, which has been sequencing Neanderthal DNA, continually faces
these problems."When you want to study ancient human and Neanderthal remains,
there's a big issue of contamination with contemporary human DNA," he says.
12.This doesn't mean that all museum specimens are fatally flawed, notes P
bo.The Neanderthal fossils that were recently sequenced in his own lab, for
example, had been part of a museum collection treated in the traditional way.But
P bo is keen to see samples of fossils from every major find preserved in line
with Geigl's recommendations — just in case.
Warm and wet
13.Geigl herself believes that, with cooperation between bench and field
researchers, preserving fossils properly could open up avenues of discovery that
have long been assumed closed.
14.Much human cultural development took place in temperate regions.DNA does
not survive well in warm environments in the first place, and can vanish when
fossils are washed and treated.For this reason, Geigl says, most ancient DNA
studies have been done on permafrost samples, such as the woolly mammoth, or on
remains sheltered from the elements in cold caves — including cave bear and
Neanderthal fossils.
15.Better conservation methods, and a focus on fresh fossils, could boost DNA
extraction from more delicate specimens, says Geigl.And that could shed more
light on the story of human evolution.
(640 words nature )
Glossary
Palaeontologists 古生物学家
Aurochs 欧洲野牛
Neanderthal (人类学)尼安德特人，旧石器时代的古人类。
Permafrost (地理)永冻层
Questions 1-6
Answer the following questions by using NO MORE THAN THREE WORDS for each
answer.
1.How did people traditionally treat fossils?
2.What suggestions do Geigl and her colleagues give on what should be done
when fossils are found?
3.What problems may be posed if fossil bones are washed on-site? Name
ONE.
4.What characteristic do fossil bones have to make them susceptible to be
contaminated with contemporary DNA when they are washed?
5.What could be better understood when conservation treatments are
improved?
6.The passage mentioned several animal species studied by researchers.How
many of them are mentioned?
Questions 7-11
Do the following statements agree with the information given in the passage?
Please write TRUE if the statement agrees with the writer FALSE if the statement
does not agree with the writer NOT GIVEN if there is no information about this
in the passage.
7.In their paper published in the Proceedings of the National Academy of
Sciences，Geigl and her colleagues have shown what conservation practices should
be followed to preserve ancient DNA.
8.The fossil bones that Geigl and her colleagues studied are all from the
same aurochs.
9.Geneticists don't have to work on site.
10.Only newly excavated fossil bones using new conservation methods suggested
by Geigl and her colleagues contain ancient DNA.
11.Paabo is still worried about the potential problems caused by treatments
of fossils in traditional way.
Questions 12-13
Complete the following the statements by choosing letter A-D for each
answer.
12.“This information” in paragraph 3 indicates:
[A] It is critical to follow proper practices in preserving ancient DNA.
[B] The best way of getting good DNA is to handle fossils with gloves.
[C] Fossil hunters should wear home-made hammers while digging up bones.
[D] Many palaeontologists know how one should do in treating fossils.
13.The study conducted by Geigl and her colleagues suggests:
[A] the fact that ancient DNA can not be recovered from fossil bones
excavated in the past.
[B] the correlation between the amount of burying time and that of the
recovered DNA.
[C] the pace at which DNA degrades.
[D] the correlation between conservation practices and degradation of
DNA.
Passage 3
Questions 11 to 15 are based on the following passage:
The idea of a special day to honor mothers was first put forward in America
in 1907. two years later a woman, Mrs. John Bruce Dodd, in the state of
Washington proposed a similar day to honor the head of the family—the father.
Her mother died when she was very young, and her father brought her up. She
loved her father very much.
In response to Mrs. Dodd’s idea that same year—1909, the state governor of
Washington proclaimed (宣布) the third Sunday in June Father’s Day. The idea was
officially approved by President Woodrow Wilson in 1916. in 1924, President
Calvin Coolidge recommended national observance of the occasion “to establish
more intimate (亲密) relations between fathers and their children, and to impress
upon fathers the full measure of their obligations.” The red or white rose is
recognized as the official Father’s Day flower.
Father’s Day took longer to establish on a national scale than Mother’s Day,
but as the idea grained popularity, tradesmen and manufacturers began to see the
commercial possibilities. They encouraged sons and daughters to honor their
fathers with small thank-you presents, such as a tie or pair of socks, as well
as by sending greeting cards.
During the Second World War, American servicemen stationed in Britain began
to request Father’s Day greeting cards to send home. This generated a response
with British card publishers. Though at first the British public was slow to
accept this rather artificial day, it’s now well celebrated in Britain on the
third Sunday in June in much the same way as in America.
Father’s Day seems to be much less important as occasion than the Mother’s
Day. Not many of the children offer their fathers some presents. But the
American fathers still think they are much better fated than the fathers of many
other countries, who have not even a day for their sake in name only.
11. When did Father’s Day officially begin to have national popularity?
A. 1907 B. 1909 C. 1916 D. 1924
12. Who first started the idea of holding the Father’s Day?
A. Mrs. John Bruce Dodd B. Mrs. John Bruce’s Mother
C. The government of Washington. D. Some businessmen.
13. What flower will be popular on Father’s Day?
A. Lily B. Water Lily C. Red rose or white rose D. Sunflower.
14. Which statement is true, a according to this passage?
A. It took even longer for Mother’s Day to gain national popularity.
B. The businessmen helped to make Father’s Day popular.
C. Father’s Day is only celebrated in America.
D. Father’s Day is only a trick of the businessmen to make money.
15. What was the first reaction of the British publishing towards Father’s
Day?
A. They thought highly of it and accepted it at once.
B. They just accepted it at once without any hesitation.
C. They just thought it a joke.
D. They thought it was too artificial and took a long time to accept.
Section B
Directions: There are ten blanks in the following letter. You are required to
choose the best one from the given four choices marked A, B, C, and D. Then
write down the correct answer in the brackets. This section totals 10 points,
one point for each blank.
Dear Mr. Bush
Thank you for your 1 of January 5 for our Beauty Brand Blouses.
We are now exporting 2 of various brands, among which Beauty Brand is the
most famous. They are in great 3 abroad and our stocks are running 4 quickly.
They are popular not only for their novel design, but also for the reasonable
prices. We are confident that once you have tried our blouses, you will place
repeat orders with us 5 large quantities.
As you requested, we are now 6 as follows:
Price: US$600 per dozen CIF New York
Terms of Payment: By sight L/C to be opened through a bank to be 7 by the
Sellers.
Shipment: In March 2007.
Please note that we do not allow any commission 8 our blouses, but a discount
of 5% may be 9 if the quantity is more than 1,000 dozen.
The above offer is made without 10 and is subject to our final
confirmation.
We hope that you will place an order with us at an early date.
Sincerely yours
( )1. A. request B. enquiry C. acquisition D. requirement
( )2. A. blouses B. woman blouses C. woman shirts D. lady shirts
( )3. A. need B. want C. require D. demand
( )4. A. up B. off C. down D. away
( )5.A. at B. for C. in D. with
( )6. A. ordering B. offering C. placing D. advising
( )7. A. agreed B. approved C. acceptable D. covered
( )8. A. on B. in C. of D. at
( )9. A. provided B. supplied C. furnished D. granted
( )10. A. promise B. duty C. engagement D. onus
In the earliest stages of man's development he had nomore need of money than animals have.He was content with very simple forms of shelter,made his own rough tools and weapons and could provide food and clothing for himself and his family from natural materials around him.As he became more civilized,however,he began to want better shelter,more efficient tools and weapons,and more comfortable and more lasting clothing than could be provided by his own neighborhood or by the work of his own unskilled hands.For these things he had to turn to the skilled people such as smiths,leather workers or carpenters.It was then that the question of payment arose.
At first he got what he wanted by a simple process ofexchange.The smith who had not the time to look after land or cattle was glad to take meat or grain from the farmer inexchange for an axe or a plough.But as more and more goods which had no fixed exchange value came on the market,exchange became too complicated to be satisfactory.Another problem arose when those who made things wanted to get stocks of wood or leather,or iron,but had nothing to offer in exchange until their finished goods were ready. Thus the difficulties of exchange led by degrees to the invention of money.In some countries easily handled things like seeds or shells were given a certain value and the farmer,instead of paying the smith for a new axe by giving him some meat or grain,gave him so many shells.If the smith had any shells left when he had bought his food,he could get stocks of the raw materials of his trade.In some countries quite large things such as cows or camels or even big flat stones were used for trade.Later,pieces of metal,bearing values according to the rarity of the metal and the size of the pieces,or coins were used.Money as we know it had arrived.
1.Exchange of goods became difficult because _________.
A man became more civilized
B smiths began to look after land or cattle in their spare time
C more and more goods which had no fixed exchange alues came to the
marker
D farmers hadn't enough grain or meat to provide for
skilled workers
2.Money was not used until _______.
A paper was invented
B people practiced a simple process of exchange
C nothing could be offered in exchangeD the exchange of one thing for another became too complicated
3.The best title for this passage is _____.
A What is money
B What are money's functions.
C The importance of money
D The beginning of money
