绿色安全网站
  • 文摘首页
  • 教学论文
  • 实用文档
  • 个人简历
  • 论文中心
  • 演讲范文
  • 英语学习
  • 党团社会
  • 职场技巧
  • 作文园地
  • 法律文书
  • 幼儿教育
  • 故事大王
  • 教育论文
  • 节日庆典
  • 高考频道
  • 心灵鸡汤
  • 英文散文
  • 英文诗词
  • 英文原版
  • 文学文化
  • 新鲜短文
  • 少儿读物
  • 初级阅读
  • 高级精读
  • 英汉双语
  • 阅读技巧
  • 报刊文摘
  • 科普读物
  • 英文小说
  • Cracking the Neanderthal code

    Two new studies show how to sequence the genome of an extinct species


    RECREATING dinosaurs may be the stuff of science fiction—but scientists have for some years been able to extract information from the remains of species that no longer walk the Earth. Unfortunately this evidence is often in the form of tiny, jumbled snippets and it is frequently contaminated. Two new ways to patch the oddments together and distinguish genuine from false information are reported this week. Scientists intend to use the techniques to produce the complete genome of a creature that is not only extinct but also happens to be their closest relative.

    When humans first emerged as a species they shared the planet with many types of ape. The fossilised remains of one such species were discovered in the Neander Valley in Germany some 150 years ago. Neanderthal man, as the species has come to be called, was shorter and stockier than humans. The evidence suggests that he was a cousin rather than an ancestor of humanity. Mitochondrial extracted from the bones of Neanderthals does not resemble from any known modern humans, so scientists have concluded that there was no interbreeding between the two, which is what distinguishes one species from another.

    Nevertheless Neanderthal man is thought to be man's closest relative. If scientists could recreate his genome, the strings of billions of letters that spell out how to build and run a Neanderthal, they would be able to pinpoint the precise difference between the two species. Moreover, by comparing the two genomes, they could see what makes people human. Until now many researchers have argued that it would be impossible to sequence the entire genome of an extinct creature because the samples are so degraded. How could so many tiny fragments of be pieced together? And how would it be possible to check whether the jigsaw pieces had been assembled correctly?

    相关文章
    热门文章
    [设为首页]  [加入收藏]                   RSS
    热门英文原版
    最新英文原版
    热门范文
    党团范文
    简历范文
    法律范文
    热门作文
    幼儿教育