Diversification and hybridization in Andinocleome (Cleomaceae)

Area of Science:

• Botany
• Molecular Systematics
• Population Genetics

Background:

• The genus Andinocleome (Cleomaceae) is a complex group with eight species, exhibiting morphological variation, unclear species boundaries, and suspected hybridization.
• Understanding these dynamics is crucial for plant evolutionary studies.

Purpose of the Study:

• To resolve species boundaries and identify genetic diversity within Andinocleome.
• To assess the utility of the Angiosperms353 probe set for population-level studies using herbarium specimens.

Main Methods:

• Target sequence capture (Hyb-Seq) using the Angiosperms353 probe set on 65 herbarium vouchers.
• Combined data with 112 existing sequences for nuclear phylogenetic analysis.
• Constructed chloroplast phylogenetic tree using off-target regions.
• Employed STRUCTURE, PCA, SNaQ, and HyDe for hybridization analysis.

Main Results:

• The nuclear phylogenetic tree successfully resolved species boundaries within Andinocleome.
• Discordance between nuclear and chloroplast trees indicated introgressive hybridization.
• Genetic variation was identified within intraspecific populations, including A. anomala.
• Hybridization was supported between multiple species.

Conclusions:

• This study provides a robust phylogenetic framework for Andinocleome, clarifying species boundaries despite extensive hybridization.
• The Angiosperms353 probe set is effective for population structuring analysis, even with historical herbarium samples.
• This represents the most comprehensive genetic investigation of Andinocleome to date.