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Updated: Jul 12, 2026

Assessment of DNA Contamination in RNA Samples Based on Ribosomal DNA
Published on: January 22, 2018
Group-I introns with unusual sequences occur at three sites in nuclear 18S rRNA genes of Acanthamoeba lenticulata
J M Schroeder-Diedrich1, P A Fuerst, T J Byers
1Department of Molecular Genetics, The Ohio State University, 484 W 12th Avenue, Columbus, OH 43210-1292, USA.
Abstract:
Seven of eleven isolates of Acanthamoeba lenticulata were found to have group-I introns located at one of three positions within the 18S rRNA gene. The introns are 636-721-bp long and are absent from mature rRNA. They lack open reading frames that could encode any known endonucleases. Sequences of introns from the same site in different isolates are 86.0-98.9% identical, while from different sites they are 24.2-29.8% identical. The most closely related introns from other organisms are in the 18S rRNA genes of several green algae where the 17.0-23.6% identity is mostly limited to a highly conserved core of base pairs including P, Q, R and S. Because the A. lenticulata introns only occur in one Acanthamoeba lineage, they were probably acquired after the divergence of this species.
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