• 我要登录|
  • 免费注册
    |
  • 我的丁香通
    • 企业机构:
    • 成为企业机构
    • 个人用户:
    • 个人中心
  • 移动端
    移动端
丁香通 logo丁香实验_LOGO
搜实验

    大家都在搜

      大家都在搜

        0 人通过求购买到了急需的产品
        免费发布求购
        发布求购
        点赞
        收藏
        wx-share
        分享

        Chromosome (DNA) walking

        互联网

        3584

        This technique can be used to isolate overlapping DNA fragments starting with a previously cloned DNA fragment that maps near a gene of interest (dark red). The walk is continued until a clone containing the desired gene is identified.

        In this example, the chromosomal DNA fragments are cloned in λ phage. The starting clone (green) is used as a probe to screen a genomic DNA library for overlapping sequences; usually a walk is conducted in both directions, since it generally is not known how far the gene of interest is from the starting clone or whether it is to the left or right.

        For simplicity, a one-way walk is illustrated here. The clones isolated in the walk are used as probes in Southern blot analysis of genomic DNA from mutants.

        This analysis can detect chromosomal deletions and rearrangements in the mutant DNA , but normally cannot detect point mutations unless they change the restriction-site sequences recognized by the restriction enzymes used in the analysis.

        In this way, the DNA clone containing the region corresponding to the gene of interest can be identified. Normally, a walk would involve more than the three steps shown here. In some cases, part of the desired gene may already be cloned, and DNA walking may be necessary to isolate the entire gene.

        By initiating walks from several different starting clones in parallel (these walks will eventually link up), the process of isolating overlapping clones for long contiguous stretches of DNA is accelerated. [From J. D. Watson et al., 1992, Recombinant DNA , 2d ed., W. H. Freeman and Company, p. 128.]

        ad image
        提问
        扫一扫
        丁香实验小程序二维码
        实验小助手
        丁香实验公众号二维码
        扫码领资料
        反馈
        TOP
        打开小程序