Genetic Diversity and Population Structure in Bryophyte With Facultative Nannandry

Area of Science:

• Botany
• Evolutionary Biology
• Population Genetics

Background:

• Gender dimorphism is observed in approximately 10% of angiosperms and over 50% of moss taxa.
• Dwarf males (DMs) are exclusively found in certain unisexual mosses, representing a unique reproductive strategy.

Purpose of the Study:

• To investigate the reproductive strategy of facultative male dwarfism in the moss Dicranum scoparium.
• To compare genetic variability and structure among females, dwarf males (DMs), and normal-sized males (NMs) across different geographic scales.

Main Methods:

• Utilized 119 SNP markers derived from transcriptomes for genotyping 403 samples.
• Analyzed genetic variability and structure at cushion, site, and locality levels in southern Sweden.

Main Results:

• Dwarf males (DMs) outnumbered females and normal-sized males (NMs) where present.
• Low genetic differentiation was observed at the locality level, with stronger differentiation between cushions for females and NMs.
• Dwarf males (DMs) and females exhibited similar genetic diversity, while NMs showed lower diversity and higher clonality.

Conclusions:

• Dwarf males (DMs) and normal-sized males (NMs) fulfill different reproductive functions in Dicranum scoparium.
• Inbreeding may occur at the cushion level, but high gene flow prevents significant genetic drift.