Retroposon Mapping in Molecular Systematics

  • Norihiro Okada
  • Andrew M. Shedlock
  • Masato Nikaido
Part of the Methods in Molecular Biology book series (MIMB, volume 260)


Advances in genome sciences are demonstrating the dynamic nature of noncoding DNA regions, which are comprised largely of repetitive elements with no apparent function. Retroposons are one class of mobile genetic elements that amplify and move about the genome via a copy-and-paste mechanism that employs an RNA intermediate. Short and long interspersed elements (SINEs and LINEs, respectively) are types of retroposons of particular interest because of their active role in shaping the architecture of genomes and their diagnostic value as evolutionary markers for studies of phylogeny and population biology. Although the use of SINEs and LINEs for molecular systematic studies is proliferating, a comprehensive laboratory protocol that explicitly outlines how to isolate and characterize retroposons for systematic studies in a detailed, step-by-step fashion has been lacking. The present chapter addresses this gap in the literature by focusing on the strategy for isolating new SINEs from a genomic library, the screening process, the sequencing and characterization of clones into subfamilies, quantification of copy number in host taxa, and the critical diagnosis of phylogenetically informative SINE and LINE insertion patterns. Practical limits to the method are discussed in relation to sampling design, systematic character theory, and the empirical distribution of elements observed in eukaryotic lineages. Major steps in the experimental process are illustrated with case examples from a diversity of taxonomic groups and by published results in the molecular biology and systematics literature.

Key Words

DNA repeat mobile DNA interspersed element retroposon SINE LINE retrotransposition reverse transcriptase cDNA RNA systematics genomics eukaryote 


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Copyright information

© Humana Press Inc., Totowa, NJ 2004

Authors and Affiliations

  • Norihiro Okada
    • 1
  • Andrew M. Shedlock
    • 2
  • Masato Nikaido
    • 1
  1. 1.Faculty of Bioscience and BiotechnologyTokyo Institute of TechnologyYokohamaJapan
  2. 2.Department of ZoologyUniversity of WashingtonSeattle

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