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Recurrent gains and losses of large (84–109 bp) repeats in the rDNA internal transcribed spacer 2 (ITS2) of rhipicephaline ticks
Author(s) -
Murrell A.,
Campbell N. J. H.,
Barker S. C.
Publication year - 2001
Publication title -
insect molecular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.955
H-Index - 93
eISSN - 1365-2583
pISSN - 0962-1075
DOI - 10.1046/j.0962-1075.2001.00298.x
Subject(s) - internal transcribed spacer , biology , subfamily , concerted evolution , spacer dna , inverted repeat , genetics , direct repeat , ribosomal dna , evolutionary biology , phylogenetics , ribosomal rna , gene , base sequence , genome
We studied the internal transcribed spacer 2 (ITS2) in twenty‐two spp. of ticks from the subfamily Rhipicephalinae. A 104–109 base pair (bp) region was imperfectly repeated in most ticks studied. Mapping the number of repeat copies on to a phylogeny from the ITS2 showed that there have been many independent gains and losses of repeats. Comparison of the sequences of the repeat copies indicated that in most taxa concerted evolution had played little if any role in the evolution of these regions, as the copies clustered by sequence position rather than species. In our putative secondary structure, each repeat copy can fold into a distinct and almost identical stem‐loop complex; a gain or loss of a repeat copy apparently does not impair the function of the ITS2 in these ticks.