Evolution of the cystatin B gene: Implications for the origin of its variable dodecamer tandem repeat in humans

Motoki Osawa, Mika Kaneko, Hidekazu Horiuchi, Takashi Kitano, Yoshi Kawamoto, Naruya Saitou, Kazuo Umetsu

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The human cystatin B gene contains a variable number of 12-bp tandem repeats in its promoter region, of which the common alleles contain two or three copies and unusual expansion causes progressive myoclonus epilepsy of the Unverricht-Lundborg type. We undertook a comprehensive analysis of the genomic sequence to address the evolutionary events of this variable repeat. By examination of a contiguous genome sequence spanning 5.0 kb and linkage analysis of detected polymorphic changes, we identified six major intragenic haplotypes in unrelated Japanese subjects. The number of normal repeats was closely correlated with these alleles, indicating that changes in the array should be comparatively rare events during human evolution. To examine the origin of the repeat array further, we also analyzed five primate genomes. Repetitive polymorphism was unlikely in hominoids, and the array originated with the dodecamer itself in the course of primate evolution. The variability conceivably developed after the separation to humans.

Original languageEnglish
Pages (from-to)78-84
Number of pages7
JournalGenomics
Volume81
Issue number1
DOIs
Publication statusPublished - 2003 Jan 1
Externally publishedYes

Keywords

  • Cystatin B
  • Molecular evolution
  • Primates
  • VNTR

ASJC Scopus subject areas

  • Genetics

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