Origin, genetic structure and evolutionary potential of the natural hybrid Ranunculus circinatus × R. fluitans

Area of Science:

• Botany
• Evolutionary Biology
• Genetics

Background:

• Interspecific hybridization is a key evolutionary process in plants.
• Understanding genetic variability in hybrids informs their adaptive potential.
• Ranunculus sect. Batrachium (Ranunculaceae) is known for spontaneous hybridization.

Purpose of the Study:

• To investigate the genetic variation and structure of the interspecific hybrid Ranunculus circinatus × R. fluitans.
• To explore the role of hybridization and polyploidy in the evolution of Ranunculus sect. Batrachium.
• To determine the potential for fertility recovery and speciation in sterile hybrids.

Main Methods:

• Genome-wide DNA fingerprinting using amplified fragment length polymorphisms (AFLP).
• Analysis of 36 riverine populations of the hybrid and its parental species.
• Assessment of genetic structure, ploidy, and gamete formation.

Main Results:

• Strong genetic structure observed in R. circinatus × R. fluitans populations in Poland.
• Hybridization events, sterility, vegetative propagation, and geographical isolation contribute to genetic structure.
• The sterile triploid hybrid can participate in subsequent hybridization, leading to fertility recovery through ploidy changes.
• Production of unreduced female gametes by the hybrid and R. fluitans is a significant evolutionary mechanism.

Conclusions:

• The hybrid R. circinatus × R. fluitans exhibits significant genetic structuring.
• Sterile hybrids in Ranunculus sect. Batrachium possess mechanisms for evolutionary innovation.
• The capacity for unreduced gamete formation facilitates fertility restoration and the potential origin of new taxa.