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Evolution of the cryptic FMR1 CGG repeat

Nature Genetics volume 11, pages 301–308 (1995)Cite this article

Abstract

We have sequenced the 5′ untranslated region of the orthologous FMR1 gene from 44 species of mammals. The CGG repeat is present in each species, suggesting conservation of the repeat over 150 million years of mammalian radiation. Most mammals possess small contiguous repeats (mean number of repeats = 8.0 +/− 0.8), but, in primates, the repeats are larger (mean= 20.0 +/− 2.3) and more highly interrupted. Parsimony analysis predicts that enlargement of the FMR1 CGG repeat beyond 20 triplets has occurred in three different primate lineages. In man and gorilla, AGG interruptions occur with higher–order periodicity, suggesting that historical enlargement has involved incremental and vectorial addition of larger arrays demarcated by an interruption. Our data suggest that replication slippage and unequal crossing over have been operative during the evolution of this repeat.

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Authors and Affiliations

  1. Department of Molecular and Human Genetics, Human Genome Center, Baylor College of Medicine, Houston, Texas, 77030, USA

    Evan E. Eichler, Kellie A. Lugenbeel & David L. Nelson

  2. Howard Hughes Medical Institute, Departments of Biochemistry and Pediatrics, Emory University, School of Medicine, Atlanta, Georgia, 30322, USA

    Catherine B. Kunst & Stephen T. Warren

  3. Center for Reproduction of Endangered Species, Zoological Society of San Diego, San Diego, California, 92112, USA

    Oliver A. Ryder

  4. Department of Biochemical and Biophysical Sciences and Computer Science, University of Houston, 4800 Calhoun, Houston, Texas, 77024-5934, USA

    Daniel Davison

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Eichler, E., Kunst, C., Lugenbeel, K. et al. Evolution of the cryptic FMR1 CGG repeat. Nat Genet 11, 301–308 (1995). https://doi.org/10.1038/ng1195-301

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