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Patterns of intron sequence conservation in the genus Tetrahymena

Yichen Zheng
  • Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204, USA
  • Email:
/ Kristen L. Dimond
  • Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204, USA
/ Dan Graur
  • Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204, USA
/ Rebecca A. Zufall
  • Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204, USA
Published Online: 2013-02-27 | DOI: https://doi.org/10.2478/prge-2013-0001



Introns constitute a large fraction of eukaryotic genomes and were once considered neutrally evolving sequences. Recently, however, some introns have been found to harbor sequences that are involved in a variety of regulatory and other functions and show evidence of purifying selection.


We examine the pattern of sequence divergence among ciliates in the genus Tetrahymena. We find that on average introns are more highly conserved than four-fold degenerate sites. Among introns, we find a correlation between conservation strength and both position rank in the gene as well as size of the coding region; the most conserved introns are found closer to the 5’ end of the largest genes.


Our results indicate that Tetrahymena introns experience selective constraint, possibly due to harboring regulatory sequences. We advocate for further experimental study of possible intron functions in Tetrahymena.

Keywords: Intron; Evolution; Ciliate; Tetrahymena

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About the article

Received: 2012-08-08

Accepted: 2013-01-14

Published Online: 2013-02-27

Citation Information: Protist Genomics, ISSN (Online) 2299-100X, DOI: https://doi.org/10.2478/prge-2013-0001. Export Citation

©2013 Versita Sp. z o.o.. This content is open access.

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