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Case studies and mathematical models of ecological speciation 3: Ecotype formation in a Swedish snail

Sadedin, Suzanne; Hollander, Johan LU ; Panova, Marina; Johannesson, Kerstin and Gavrilets, Sergey (2009) In Molecular Ecology 18(19). p.4006-4023
Abstract
Formation of partially reproductively isolated ecotypes in the rough periwinkle, Littorina saxatilis, may be a case of incipient nonallopatric ecological speciation. To better understand the dynamics of ecotype formation, its timescale, driving forces and evolutionary consequences, we developed a spatially explicit, individual-based model incorporating relevant ecological, spatial and mate selection data for Swedish L. saxatilis. We explore the impact of bounded hybrid superiority, ecological scenarios and mate selection systems on ecotype formation, gene flow and the evolution of prezygotic isolation. Our model shows that ecotypes are expected to form rapidly in parapatry under conditions applicable to Swedish L. saxatilis and may proceed... (More)
Formation of partially reproductively isolated ecotypes in the rough periwinkle, Littorina saxatilis, may be a case of incipient nonallopatric ecological speciation. To better understand the dynamics of ecotype formation, its timescale, driving forces and evolutionary consequences, we developed a spatially explicit, individual-based model incorporating relevant ecological, spatial and mate selection data for Swedish L. saxatilis. We explore the impact of bounded hybrid superiority, ecological scenarios and mate selection systems on ecotype formation, gene flow and the evolution of prezygotic isolation. Our model shows that ecotypes are expected to form rapidly in parapatry under conditions applicable to Swedish L. saxatilis and may proceed to speciation. However, evolution of nonrandom mating had complex behaviour. Ecotype evolution was inhibited by pre-existing mating preferences, but facilitated by the evolution of novel preferences. While in many scenarios positive assortative mating reduced gene flow between ecotypes, in others negative assortative mating arose, preferences were lost after ecotype formation, preferences were confined to one ecotype or the ancestral ecotype became extinct through sexual selection. Bounded hybrid superiority (as observed in nature) enhanced ecotype formation but increased gene flow. Our results highlight that ecotype formation and speciation are distinct processes: factors that contribute to ecotype formation can be detrimental to speciation and vice versa. The complex interactions observed between local adaptation and nonrandom mating imply that generalization from data is unreliable without quantitative theory for speciation. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Littorina, parapatric, prezygotic, reproductive isolation, simulation
in
Molecular Ecology
volume
18
issue
19
pages
4006 - 4023
publisher
Wiley-Blackwell
external identifiers
  • scopus:70349319862
ISSN
0962-1083
DOI
10.1111/j.1365-294X.2009.04320.x
language
English
LU publication?
no
id
d7fca6f1-82e8-4a85-a054-38d26919d039 (old id 1982130)
date added to LUP
2011-08-17 12:41:58
date last changed
2017-11-12 03:18:45
@article{d7fca6f1-82e8-4a85-a054-38d26919d039,
  abstract     = {Formation of partially reproductively isolated ecotypes in the rough periwinkle, Littorina saxatilis, may be a case of incipient nonallopatric ecological speciation. To better understand the dynamics of ecotype formation, its timescale, driving forces and evolutionary consequences, we developed a spatially explicit, individual-based model incorporating relevant ecological, spatial and mate selection data for Swedish L. saxatilis. We explore the impact of bounded hybrid superiority, ecological scenarios and mate selection systems on ecotype formation, gene flow and the evolution of prezygotic isolation. Our model shows that ecotypes are expected to form rapidly in parapatry under conditions applicable to Swedish L. saxatilis and may proceed to speciation. However, evolution of nonrandom mating had complex behaviour. Ecotype evolution was inhibited by pre-existing mating preferences, but facilitated by the evolution of novel preferences. While in many scenarios positive assortative mating reduced gene flow between ecotypes, in others negative assortative mating arose, preferences were lost after ecotype formation, preferences were confined to one ecotype or the ancestral ecotype became extinct through sexual selection. Bounded hybrid superiority (as observed in nature) enhanced ecotype formation but increased gene flow. Our results highlight that ecotype formation and speciation are distinct processes: factors that contribute to ecotype formation can be detrimental to speciation and vice versa. The complex interactions observed between local adaptation and nonrandom mating imply that generalization from data is unreliable without quantitative theory for speciation.},
  author       = {Sadedin, Suzanne and Hollander, Johan and Panova, Marina and Johannesson, Kerstin and Gavrilets, Sergey},
  issn         = {0962-1083},
  keyword      = {Littorina,parapatric,prezygotic,reproductive isolation,simulation},
  language     = {eng},
  number       = {19},
  pages        = {4006--4023},
  publisher    = {Wiley-Blackwell},
  series       = {Molecular Ecology},
  title        = {Case studies and mathematical models of ecological speciation 3: Ecotype formation in a Swedish snail},
  url          = {http://dx.doi.org/10.1111/j.1365-294X.2009.04320.x},
  volume       = {18},
  year         = {2009},
}