双语：科学家利用DNA分析技术保护非洲大象

WASHINGTON - The complex science of DNA analysis is now helping protect elephants by showing police and conservationists the source of black-market ivory.

   The price of ivory has nearly quadrupled in recent years, prompting poachers to kill more elephants to sell their tusks illegally. Protecting the giant beasts is complicated by the fact they spread across large parts of Africa and authorities are unsure where the illegal hunting is occurring.

  But the seizure of more than six tons of ivory in Singapore in 2002 has helped solve part of that puzzle, according to a report by Samuel K. Wasser of the Center for Conservation Biology at the University of Washington in this week's online edition of Proceedings of the National Academy of Sciences.
  Wasser and colleagues took samples of the confiscated ivory and compared it with baseline DNA collected from elephants across the continent over several years. DNA is the internal blueprint for life that carries the genes that develop into each individual.

  The comparison showed that the tusks seized from the black market came from elephants on Africa's broad savannas, primarily from a small area of southern Africa, most likely centered on Zambia, the researchers said.

   Authorities had suspected the confiscated ivory had multiple origins, the researchers said, but \"our results caused law enforcement to substantially narrow the area of origin and the trade routes being investigated.\"
　　The research was funded by the U.S. Fish and Wildlife Service, African Elephant Conservation Fund, the International Fund for Animal Welfare, the Gordon and Betty Moore Foundation and the Center for Conservation Biology.



中文链接：
   如今，DNA分析技术已经成为了致力于大象保护工作者手中的一件新武器，人们可以通过运用此项技术来追查那些在黑市上被交易的象牙的原产地。
   象牙的价格在最近几年里几乎上涨了300％，这使得那些偷猎者们疯狂屠杀大象以便在非法倒卖象牙中牟利暴力。由于大象在非洲大陆上分布的区域十分辽阔，所以对大象的保护工作就显得困难重重了，有关当局往往无法确定那些非法盗猎活动到底是在哪里发生的。
   瓦塞尔及其同事从2002年在新加坡没收的6吨象牙上采集了相关的样本，并把它们与此前几年间在非洲大陆上收集到的大象基线DNA进行了比对。DNA堪称是所有生命体体内均具有的一张“蓝图”，正是在它的“指引”下各种不同的基因沿着特定的路线逐步发育成长，最后便形成了诸多互不相同的个体。DNA比对的结果表明，这些黑市上罚没的象牙其实来自于生活在非洲大陆广袤的热带大草原上的大象口中，其中最主要的“产地”便是位于南部非洲的一个狭小区域，而其中心点极有可能就在赞比亚的境内。
   有关方面曾经怀疑这些被没收的象牙来源于多个不同的地方，研究人员表示，但是“我们的研究结论使得执法机构大幅缩小了象牙原产地的范围，而具体的交易路线则正处在调查之中。”这项研究工作得到了美国渔业与野生动植物管理部门、非洲大象保护基金会、国际动物福利基金会、戈登和贝蒂·摩尔基金会以及环保生物学研究中心的大力资助。