Organization of the 5s Ribosomal Dna Intergenic Spacer of Apamea Monoglypha (Lepidoptera)

Abstract

A significant part of the moth species, representatives of the superfamily Noctuoidea distributed on the territory of Ukraine, are pests of crops, which attracts special attention of researchers. In particular, host plants for the larvae of the Apamea species are cereals. For the correct identification of the pest moth speciesit is necessary to conduct molecular genetic studies to create molecular passports (barcoding). One of the convenient molecular markers used to compare low-ranking taxa is the 5S rDNA region represented by tandemly arranged clusters, where each repeat unit consists of a highly conserved coding region and a variable intergenic spacer (IGS). Since the molecular organization of 5S rDNA in moth species is still insufficiently studied, the aim of our work was to analyze the 5S rDNA IGS of A. monoglypha, a representative of the Apamea genus. For this, 5S rDNA repeats were amplified by PCR, and the obtained products were ligated into the pJet1.2 plasmid vector. The inserts of the three recombinant plasmids, ApMon1-1, ApMon1-2, and ApMon1-8, which were of the expected size, were sequenced. It was found that the A. monoglypha genome contains several structural IGS variants that differ both in length and nucleotide sequence. The level of similarity of the compared IGS sequences varied from 38.0 to 76.2%, indicating a high level of intragenomic polymorphism in this region. An AT-rich motif, a GC dinucleotide, and a cytosine residue up-stream of the coding region were identified as putative external promoter elements, which can be involved in the initiation of transcription. Furthermore, the oligo-T motif located immediately down-stream of the coding region is probably involved in the transcription termination.