海牛亚种差异性显著
文章来源:未知 文章作者:meng 发布时间:2010-09-14 03:07 字体: [ ]  进入论坛
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The first genetic2 study to compare nuclear DNA3 of endangered Antillean manatees4(海牛) in Belize with Florida manatees confirmed their designation as separate subspecies(亚种) . Belize's manatees, however, were found to have extremely low genetic diversity, raising questions about their long-term genetic viability5. The Central American country of Belize hosts the largest known breeding population of Antillean manatees and is touted6 by biologists for its potential to repopulate other parts of Central America where manatees are severely7 reduced, rare or absent.

"It turns out that the genetic diversity of Belize's manatees is lower than some of the classic examples of critically low diversity" said U.S. Geological Survey (USGS) conservation geneticist Margaret Hunter, Ph.D., who led a molecular8 DNA study of genetic diversity in the Antillean subspecies in Belize.

Belize's Antillean populations scored lower in genetic diversity than textbook examples of "bottlenecked" endangered species such as Wanglang giant pandas, the East African cheetah10(猎豹) and an island koala(树袋熊) population founded by only three koalas.

Endangered species need genetic diversity to weather threats to their survival, including random11 or rare shocks such as disease, hurricanes or habitat destruction. When a population drops to low numbers, the diversity of its gene1 pool also shrinks. Even after it rebounds12 to greater numbers, that population decline leaves a legacy13 of reduced genetic diversity known as a bottleneck9. This renders the population more vulnerable to future shocks, explained Hunter.

The low genetic diversity in Antillean manatees is attributed, in part, to centuries of hunting that were only curtailed14 early in the 20th century. Once found throughout coastal15 regions of Central and South America, Antillean manatees are now rare or absent in parts of Central America where they used to be considered abundant. Today, even Belize only hosts about 1,000 individuals — a number well below the threshold recommended for long-term sustainability, said Hunter.

Distinct Populations Offer Opportunity

Although the study found low overall genetic diversity in Belize, notable differences were found in manatees that live near Belize City compared to manatees living in lagoons16(泻湖,池塘) , rivers, and cayes farther south. These differences, said Hunter, equate17 to genetic variation, which is valuable for sustaining a diverse gene pool.

"When it comes to the sustainability of a species, this is the type of genetic diversity you want to preserve for the future," explained Hunter.

To sustain the diverse gene pool these populations offer, managers will need to consider methods of enabling natural migration18 and mixing to take place between the two populations.

"These results show the importance of corridors of suitable habitat and low human impact that allow manatees to travel between key sites," said co-author Nicole Auil Gomez, a Belizean biologist who does consulting for the Florida-based conservation organization Sea 2 Shore Alliance.

"Leaving pockets of habitat is no longer enough," she added.



点击收听单词发音收听单词发音  

1 gene WgKxx     
n.遗传因子,基因
参考例句:
  • A single gene may have many effects.单一基因可能具有很多种效应。
  • The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。
2 genetic PgIxp     
adj.遗传的,遗传学的
参考例句:
  • It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
  • Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
3 DNA 4u3z1l     
(缩)deoxyribonucleic acid 脱氧核糖核酸
参考例句:
  • DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
  • Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
4 manatees 838c504e9733f033c37f82abeb0e60f1     
n.海牛(水生哺乳动物,体宽扁,尾圆,有鳃状肢)( manatee的名词复数 )
参考例句:
  • The manatees tamed quickly. 海牛很快地被驯服。 来自互联网
  • Gentle and slow moving, manatees are said to be the mythical mermaids of sailors' imaginations. 海牛游动温和而缓慢,被认为是海员遐想中富有神秘色彩的美人鱼。 来自互联网
5 viability FiHwY     
n.存活(能力)
参考例句:
  • What is required to achieve or maintain such viability? 要达到或维持这种生存能力需要什么?
  • Scientists are experimenting to find ways to ensure the viability of seeds for even longer periods of time. 正如我们所说,科学家正在试验努力寻找让种子的生命力更加延长的方法。
6 touted 00151f908b31d984fd20d8b48dba34f3     
v.兜售( tout的过去式和过去分词 );招揽;侦查;探听赛马情报
参考例句:
  • She's being touted as the next leader of the party. 她被吹捧为该党的下一任领导人。
  • People said that he touted for his mother and sister. 据说,他给母亲和姐姐拉生意。 来自辞典例句
7 severely SiCzmk     
adv.严格地;严厉地;非常恶劣地
参考例句:
  • He was severely criticized and removed from his post.他受到了严厉的批评并且被撤了职。
  • He is severely put down for his careless work.他因工作上的粗心大意而受到了严厉的批评。
8 molecular mE9xh     
adj.分子的;克分子的
参考例句:
  • The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
  • For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时,分子的碰撞就停止了。
9 bottleneck uRfyN     
n.瓶颈口,交通易阻的狭口;妨生产流程的一环
参考例句:
  • The transportation bottleneck has blocked the movement of the cargo.运输的困难阻塞了货物的流通。
  • China's strained railroads already become a bottleneck for the economy.中国紧张的铁路运输已经成为经济增长的瓶颈。
10 cheetah 0U0yS     
n.(动物)猎豹
参考例句:
  • The cheetah is generally credited as the world's fastest animal.猎豹被公认是世界上跑得最快的动物。
  • The distribution of the cheetah ranges from Africa to Central Asia.印度豹的足迹遍及从非洲到中亚的广大地区。
11 random HT9xd     
adj.随机的;任意的;n.偶然的(或随便的)行动
参考例句:
  • The list is arranged in a random order.名单排列不分先后。
  • On random inspection the meat was found to be bad.经抽查,发现肉变质了。
12 rebounds 87b0c2d1da6e752183ab26d425c5acd4     
反弹球( rebound的名词复数 ); 回弹球; 抢断篮板球; 复兴
参考例句:
  • V is the velocity after the gas particle rebounds from the wall. V是粒子从壁上弹开后的速度。
  • In the former case, the first body rebounds with practically its original velocity. 在前一种情况下,第一个物体实际上以原来的速度弹回。
13 legacy 59YzD     
n.遗产,遗赠;先人(或过去)留下的东西
参考例句:
  • They are the most precious cultural legacy our forefathers left.它们是我们祖先留下来的最宝贵的文化遗产。
  • He thinks the legacy is a gift from the Gods.他认为这笔遗产是天赐之物。
14 curtailed 7746e1f810c323c484795ba1ce76a5e5     
v.截断,缩短( curtail的过去式和过去分词 )
参考例句:
  • Spending on books has been severely curtailed. 购书开支已被大大削减。
  • Their public health programme had to be severely curtailed. 他们的公共卫生计划不得不大大收缩。 来自《简明英汉词典》
15 coastal WWiyh     
adj.海岸的,沿海的,沿岸的
参考例句:
  • The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
  • This country will fortify the coastal areas.该国将加强沿海地区的防御。
16 lagoons fbec267d557e3bbe57fe6ecca6198cd7     
n.污水池( lagoon的名词复数 );潟湖;(大湖或江河附近的)小而浅的淡水湖;温泉形成的池塘
参考例句:
  • The Islands are by shallow crystal clear lagoons enclosed by coral reefs. 该群岛包围由珊瑚礁封闭的浅水清澈泻湖。 来自互联网
  • It is deposited in low-energy environments in lakes, estuaries and lagoons. 它沉淀于湖泊、河口和礁湖的低能量环境中,也可于沉淀于深海环境。 来自互联网
17 equate NolxH     
v.同等看待,使相等
参考例句:
  • You can't equate passing examination and being intelligent.你不能把考试及格看成是聪明。
  • You cannot equate his poems with his plays.你不可以把他的诗歌和他的剧本相提并论。
18 migration mDpxj     
n.迁移,移居,(鸟类等的)迁徙
参考例句:
  • Swallows begin their migration south in autumn.燕子在秋季开始向南方迁移。
  • He described the vernal migration of birds in detail.他详细地描述了鸟的春季移居。
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