Genome wide analysis of 5s ribosomal RNA genes in Gentiana macrophylla

Due to their unique structure, 5S rRNA genes are used in research of genome evolution and as a molecular marker. Aim. The aim of the study was to investigate the intergenic spacer (IGS) of 5S rRNA genes of Gentiana macrophylla Pall. Methods. The bioinformatic analysis of nucleotide sequences of 5S rDNA IGS found by searching the reference G. macrophylla genome was conducted. Results. It was determined that the majority of 5S rRNA genes in the G. macrophylla genome (approximately 460 copies) are arranged as tandem repeats on chromosome 7. The IGS region was found to be variable in terms of length and sequence, and all repeats were divided into four classes. Of these, 84% were similar in their nucleotide sequence to 5S rDNA IGS of two other species of the Cruciata section. The IGS of all classes contains regulatory elements typical for 5S rDNA of other flowering plants. The differences among the various classes are attributable to the presence of duplicated regions at the beginning of the IGS. This mechanism of IGS evolution due to the duplication at the beginning of the spacer has been previously identified in other gentians. Conclusions. The data obtained indicate the existence of different variants of 5S rDNA repeats in the G. macrophylla genome, which may provide the basis for genetic plasticity.