英語聽力文摘 DNA幫助捕獲偷獵者
DNA Helps Catch Poachers
科學(xué)家們利用一種革命性的基因技術(shù)成功確定了走私犯屠宰大象的非洲地區(qū)，這些大象淪為全世界非法象牙貿(mào)易的受害者。利用非洲大象的DNA圖譜，他們已發(fā)現(xiàn)最近緝獲的象牙來自坦桑尼亞和莫桑比克邊界的塞盧斯及尼亞薩兩個禁獵區(qū)的大象。這一發(fā)現(xiàn)表明，應(yīng)對世界上大部分日益猖獗的非法象牙貿(mào)易以及每年遭到屠殺的成千上萬頭大象負(fù)責(zé)的，只是少數(shù)卡特爾組織。最近在臺灣、香港、越南、菲律賓和日本分別獨立發(fā)起的碼頭突擊搜查中緝獲了數(shù)以千計的象牙，這揭示了這種非法貿(mào)易的嚴(yán)重程度。這些象牙都是為了滿足遠(yuǎn)東日益增長的象牙需求，象牙成為該區(qū)域日益膨脹的工業(yè)化經(jīng)濟(jì)體中中產(chǎn)階級社會地位的新象征。因此，象牙價格已從2004年每公斤200美元飆升到了每公斤6,000多美元。與此同時，科學(xué)家們估計，目前每年有8%至10%的非洲大象正在遭到捕殺以滿足市場需求。
Find out how DNA can help catch poachers, on this Moment of Science.
The OJ Simpson trial put DNA testing as a forensics(辯論術(shù)) tool in the spotlight. Now DNA’s use in identifying criminals is nothing new, but what is new is its use to identify a different kind of criminal–elephant poachers.
In the 1980’s, the number of African elephants dropped from 1.3 million to about 500,000. In order to protect the elephants, an international ban(禁令) on the selling of African ivory was implemented(實施), but that didn’t stop poachers.
One difficulty law enforcers(實施者) face in tracking(跟蹤) poachers is that it’s difficult to know where exactly (2)poaching(非法獵取) is most concentrated(集中的). That’s where DNA testing comes in.
There are two different species of African elephant, savanna(熱帶草原) elephants, which inhabit the grassy(長滿草的) plains and bushland(原始林區(qū)), and forest elephants, which live in the equatorial(赤道的) forests. DNA testing can distinguish not only the ivory of savanna elephants from that of forest elephants, but it can to a large degree (3)decipher(解釋) what region an elephant comes from.
All that genetic testing requires is a small sample from the core of an elephant tusk(長牙), about the size of a kernel(核心，要點) of corn. Ivory tusks are teeth, and they’re made of a material called dentin(象牙質(zhì)). Because dentin is secreted(分泌) by cells in the jaws, scientists predicted that DNA from these cells might be found inside the dentin.
They did indeed find DNA in the tusks and by comparing it to a database of elephants from across the continent of Africa, they’ve been able to locate where the elephant comes from. This enables law enforcers to concentrate their efforts in regions where poaching is most threatening(危險的). It’s yet another example of DNA’s use in solving crimes.
Notes:
(1)forensics [f?'rensiks] n. 辯論術(shù);辯論練
Computer Forensics in the fight against computer crime and network in a very critical role.
計算機取證在打擊計算機和網(wǎng)絡(luò)犯罪中作用十分關(guān)鍵。
(2)poach [p?ut?] vt.水煮;偷獵;竊取;把…踏成泥漿 vi.偷獵;侵犯;剽竊
1.A new political party usually poach idea from its rival.
新政黨往往把敵對政黨的思想攫為己有。
2.I stole his bride. I guess it's OK to poach the florist.
我偷了他的新娘，我想把他的花商偷來應(yīng)該沒問題吧。
(3)decipher[di'saif?] n. 密電譯文 vt.解釋，譯解
1.Several African universities now have programmes to decipher the paintings and carvings.
現(xiàn)在幾所非洲的大學(xué)有解譯些繪畫和雕刻的項目。
2.Geneticists have yet to decipher the complex code by which epigenetic marks interact with the other components of the genome.
目前，遺傳學(xué)家還未破解外遺傳標(biāo)簽與基因組其他組成之間，產(chǎn)生互動的復(fù)雜編碼。
