Nuclear DNA amounts in Macaronesian angiosperms.

Area of Science:

• Plant biology
• Genomics
• Evolutionary biology

Background:

• Macaronesian flora, particularly Canary Islands endemics, presents unique evolutionary case studies.
• Understanding nuclear DNA content (genome size) is crucial for plant evolution and ecology.
• Previous studies on Macaronesian plant genome sizes are limited.

Purpose of the Study:

• To quantify nuclear DNA contents for 104 Macaronesian angiosperms, focusing on Canary Islands endemics.
• To investigate trends in genome size across different phylogenetic levels within Macaronesia.
• To test the hypothesis that insular selection pressures favor smaller genome sizes.

Main Methods:

• Propidium iodide flow cytometry was used to determine 1C DNA values.
• Comparative analysis of genome sizes between Macaronesian and non-Macaronesian taxa.
• Correlation analysis between genome size and environmental factors on Tenerife.

Main Results:

• Nuclear DNA content varied significantly, from 0.19 pg in Descurainia bourgeauana to 7.21 pg in Argyranthemum frutescens.
• The majority of studied species exhibited small genomes (<1.6 pg).
• A trend towards smaller nuclear DNA content and genome size in Macaronesian taxa was observed compared to non-Macaronesian relatives.

Conclusions:

• Insular selection in Macaronesia appears to favor smaller nuclear genome sizes.
• Genome size variation within genera correlates with local environmental conditions on Tenerife.
• This study provides valuable genomic data for Macaronesian endemic flora.