Interstitial Arabidopsis-Type Telomeric Repeats in Asteraceae.

Area of Science:

• Plant genetics
• Evolutionary biology
• Cytogenetics

Background:

• Interstitial telomeric repeats (ITRs) are tandem repeats found within chromosomes.
• ITRs are potential markers for structural changes and evolutionary relationships.
• Previous studies highlighted ITR polymorphisms in the genus Anacyclus.

Purpose of the Study:

• To assess if ITR presence, number, and location in Asteraceae species provide phylogenetic signals.
• To investigate the evolutionary significance of ITRs across major Asteraceae subfamilies.
• To determine if ITRs can help delimit taxonomic categories within the family.

Main Methods:

• Surveyed 132 Asteraceae species, focusing on six major subfamilies.
• Utilized fluorescent in situ hybridization (FISH) with an Arabidopsis-type telomeric probe.
• Analyzed ITR site detection on mitotic chromosome karyotypes.

Main Results:

• FISH signals of ITRs were detected in Asteroideae, Carduoideae, Cichorioideae, Gymnarhenoideae, and Mutisioideae subfamilies.
• No ITR signals were found in the Barnadesioideae subfamily.
• ITR dynamics were insufficient to accurately trace complex karyological evolution in Asteraceae.

Conclusions:

• Interstitial telomeric repeats do not convey a reliable phylogenetic signal at deep or shallow evolutionary levels in Asteraceae.
• ITRs are not useful for delimiting taxonomic categories within this family.
• This conclusion may extend to other plant families like Fabaceae.