Studies of reproductive isolation are important for understanding speciation and species delimitation. We studied seven components of reproductive isolation at different taxonomic and geographical levels and their relationship with genetic distance in diploid Fragaria. Isolation was only evident between different taxa at later stages (post F1 survivorship) not at the earlier ones of fruit and seed set, F1 seed germination and survivorship. Within F. vesca, isolation at the later stages was positively correlated with genetic distance, but this was not found at interspecific levels. The lack of isolation between F. vesca and the other species at the early stages provide the chance for hybrid formation, but high levels of infertility expressed among the offspring can lead to potentially opposing evolutionary outcomes. Within F. vesca, there was evidence of unexpected isolation promoting evolutionary diversification and incipient speciation. Reproductive isolation values between sympatric and allopatric species pairs were similar and indicate a lack of reinforcement in Fragaria. This, combined with the lack of correlation between genetic distance and isolation at interspecific levels shows that genetic distance is not always proportionally correlated with the degree of isolation in plants and suggests that evolutionary processes may be playing differently in plants compared to animals.
Dataset Reproductive fitness & genetic distances in diploid Fragaria:
Levels of reproductive fitness & genetic distances in diploid Fragaria:
1) Variations in seven components of postzygotic reproductive fitness (initial fruit (berry) set, seed set, F1 hybrid seed germination, survivorship, flowering, fruit (berry) set and pollen sterility at three hierarchal taxonomic levels:
• interspecific crosses level: between F. vesca (ssp. vesca) as maternal parent and four species of F. nubicola, F. viridis, F. daltoniana and F. nipponica;
• inter-subspecific level between F. vesca ssp. vesca and F. vesca ssp. americana;
• intra-subspecific level within F. vesca ssp. vesca (between F. vesca ssp. vesca, F. vesca ssp. vesca var. alba, and F. vesca ssp. vesca f. monophylla)
2) Variations in reproductive isolation between sympatric & allopatric species pairs:
• Sympatry: F. vesca versus F. viridis;
• Allopatric: F. vesca versus F. nubicola, F. daltoniana and F. nipponica
3) Genetic distance between diploid Fragaria based on RAPDs Nei's Distance (NTSYS-pc ver. 2.02) & ITS P-distance (using sequence data presented by Potter et al. 2005 in Genbank) in PAUP (ver. 4.0b10, Swofford, 2003).
This work is licensed under a CC0 1.0 Universal (CC0 1.0) Public Domain Dedication license.
- Fragaria daltoniana
- Fragaria nubicola
- Fragaria vesca
- Fragaria vesca ssp. americana
- Fragaria vesca ssp. vesca
- Fragaria vesca ssp. vesca f. alba
- Fragaria vesca ssp. vesca var. alba
- Fragaria viridis
- postzygotic isolation
- progeny fitness