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Updated: Aug 20, 2026

RNA Next-Generation Sequencing and a Bioinformatics Pipeline to Identify Expressed LINE-1s at the Locus-Specific Level
Published on: May 19, 2019
Lineage-specific tandem repeats riding on a transposable element of MITE in Xenopus evolution: a new mechanism for
Akira Hikosaka1, Akira Kawahara
1Developmental Biology Laboratory, Faculty of Integrated Arts and Sciences, Hiroshima University, Kagamiyama 1-7-1, Higashi-Hiroshima 739-8521, Japan.
Abstract:
Xstir is a repetitive DNA sequence element that is extremely amplified as a common component of two different structures: a tandem repeat (Xstir array) and a MITE (miniature inverted-repeat transposable element) in the genome of Xenopus laevis. To elucidate the origin and evolutionary history of Xstir-related sequences, we investigated their species specificity among three Xenopus species (X. laevis, X. borealis, and X. tropicalis). Analyses by sequence alignment and digestion with restriction enzymes of genomic Xstir-related sequences revealed that the MITE (Xmix MITE) was well conserved among the three Xenopus species, with small lineage-specific differences. On the other hand, the tandem repeat element (tropXstir) in X. tropicalis was different from the Xstir that X. laevis and X. borealis have in common. Both sequences of Xstir and tropXstir were, however, different segments of the Xmix MITE. The results suggest that these tandem repeats were formed by partial tandem duplication of the MITE internal sequence in each lineage of X. tropicalis and of X. borealis/X. laevis after their branching. A molecular mechanism for creating and elongating the tandem repeats from the MITE is proposed.
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