Khusanboy Yuldashev, Bobur Karimov, Ziyoviddin Yusupov, Ergashali Ruzimatov, Munavvar Mamadjanova

Molecular characterisation and phylogenetic placement of the endemic species Helichrysum nuratavicum 

Abstract Helichrysum nuratavicum Krasch. is a narrow endemic species, found only in the Nuratau Mountains of Uzbekistan. However, its molecular characteristics and phylogenetic position remain poorly understood. In this study, we sequenced and compared the internal transcribed spacer (ITS1–5.8S–ITS2) region of Helichrysum nuratavicum with ITS sequences from closely related Helichrysum species in Central Asia. Bayesian phylogenetic analysis resolved Helichrysum nuratavicum as the sister species of Helichrysum maracandicum Popov ex Kirp., as shown by pairwise genetic distance analysis. Comparative sequence analysis identified three diagnostic nucleotide positions (438 bp, 559 bp and 576 bp), two of which (559 bp and 576 bp) were unique to Helichrysum nuratavicum. Sliding-window analysis revealed nucleotide diversity values ranging from 0.0000 to 0.0142, with the highest variability detected within the 501–595 bp region, where these two species-specific substitutions were located. These findings show that the ITS region provides sufficient phylogenetic resolution and contains informative diagnostic characters for distinguishing Helichrysum nuratavicum from closely related Central Asian Helichrysum species. The molecular data generated in this study will be a valuable resource for future taxonomic, phylogenetic, DNA barcoding, and conservation studies of this endemic species.

Doi https://doi.org/10.35513/Botlit.2026.3.1

Keywords Central Asia, diagnostic nucleotide substitutions, DNA barcoding, endemic species, molecular identification, phylogenetic analysis.

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