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Patterns of reproductive isolation in Eucalyptus - a phylogenetic perspective
Citation
Larcombe, MJ and Holland, B and Steane, DA and Jones, RC and Nicolle, D and Vaillancourt, RE and Potts, BM, Patterns of reproductive isolation in Eucalyptus - a phylogenetic perspective, Molecular Biology and Evolution, 32, (7) pp. 1833-1846. ISSN 0737-4038 (2015) [Refereed Article]
Copyright Statement
Copyright 2015 The Author
DOI: doi:10.1093/molbev/msv063
Abstract
We assess phylogenetic patterns of hybridization in the speciose, ecologically and economically important genus Eucalyptus, in order to better understand the evolution of reproductive isolation. Eucalyptus globulus pollen was applied to 99 eucalypt species, mainly from the large commercially important subgenus, Symphyomyrtus. In the 64 species that produce seeds, hybrid compatibility was assessed at two stages, hybrid-production (at approximately
1 month) and hybrid-survival (at 9 months), and compared with phylogenies based on 8,350 genome-wide DArT (diversity arrays
technology) markers. Model fitting was used to assess the relationship between compatibility and genetic distance, and whether
or not the strength of incompatibility "snowballs" with divergence. There was a decline in compatibility with increasing genetic
distance between species. Hybridization was common within two closely related clades (one including E. globulus), but rare between E. globulus and species in two phylogenetically distant clades. Of three alternative models tested (linear, slowdown, and snowball),
we found consistent support for a snowball model, indicating that the strength of incompatibility accelerates relative to
genetic distance. Although we can only speculate about the genetic basis of this pattern, it is consistent with a Dobzhansky–Muller-model
prediction that incompatibilities should snowball with divergence due to negative epistasis. Different rates of compatibility
decline in the hybrid-production and hybrid-survival measures suggest that early-acting postmating barriers developed first
and are stronger than later-acting barriers. We estimated that complete reproductive isolation can take up to 21–31 My in
Eucalyptus. Practical implications for hybrid eucalypt breeding and genetic risk assessment in Australia are discussed.
Item Details
Item Type: | Refereed Article |
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Keywords: | reproductive isolation, speciation, Dobzhansky–Muller incompatibilities, hybridization, Eucalyptus globulus, DArT markers |
Research Division: | Mathematical Sciences |
Research Group: | Applied mathematics |
Research Field: | Biological mathematics |
Objective Division: | Expanding Knowledge |
Objective Group: | Expanding knowledge |
Objective Field: | Expanding knowledge in the biological sciences |
UTAS Author: | Larcombe, MJ (Mr Matthew Larcombe) |
UTAS Author: | Holland, B (Professor Barbara Holland) |
UTAS Author: | Steane, DA (Dr Dorothy Steane) |
UTAS Author: | Jones, RC (Dr Rebecca Jones) |
UTAS Author: | Vaillancourt, RE (Professor Rene Vaillancourt) |
UTAS Author: | Potts, BM (Professor Brad Potts) |
ID Code: | 100325 |
Year Published: | 2015 |
Funding Support: | Australian Research Council (FT100100031) |
Web of Science® Times Cited: | 27 |
Deposited By: | Mathematics and Physics |
Deposited On: | 2015-05-12 |
Last Modified: | 2017-10-30 |
Downloads: | 0 |
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