# Comparison of Genomes of Species from Polemonium caeruleum Complex and Polemonium pulcherrimum Complex Based on Repeatome and Chromosome Analysis

## TL;DR

This study compares genomes of Polemonium species to understand their genetic relationships and evolutionary history.

## Contribution

The study provides new insights into the genomic and cytogenetic relationships within Polemonium complexes using repeatome and chromosome analysis.

## Key findings

- Repeatomes of species from both complexes are similar in type and number of repeats.
- Satellite DNAs show high sequence identity within species and help confirm the taxonomic status of P. kiushianum.
- Genomic analysis suggests a common ancestral genome and monophyletic origin for the studied Polemonium complexes.

## Abstract

Polemonium L. (Polemoniaceae) is a widespread genus native to subarctic and arctic regions of the Northern Hemisphere. The taxonomy and genome relationships within Polemonium are still unclear. We analyzed genomes of three species from each Polemonium caeruleum and Polemonium pulcherrimum complex using bioinformatic analysis by RepeatExplorer2/TAREAN pipelines of next-generation sequencing data. The repeatomes of all studied species were similar in type and number of repeats. Satellite DNAs (satDNAs) demonstrated high sequence identity within the studied species. FISH chromosome mapping of 45S rDNA, 5S rDNA, and two satDNAs Pol_C 33 and Pol_C 46 allowed us to construct the species karyograms and assess the genome diversity within the P. caeruleum complex and P. pulcherrimum complex, and also confirm the taxonomic status of P. kiushianum as an independent species. Our findings demonstrate a close genomic relationship among the species from P. caeruleum and P. pulcherrimum complexes, indicating the presence of a common ancestral genome; additionally, our results provide cytogenetic evidence for the monophyletic origin of these sections and also complex evolutionary history of the genus Polemonium. The developed approach may be a valuable framework for further investigation of the chromosomal organization of karyotypes in other species of the genus Polemonium.