| 1. |
- Rogell, Björn, et al.
(author)
-
Adaptive divergence in body size overrides the effects of plasticity across natural habitats in the brown trout
- 2013
-
In: Ecology and Evolution. - : Wiley. - 2045-7758. ; 3:7, s. 1931-1941
-
Journal article (peer-reviewed)abstract
- The evolution of life-history traits is characterized by trade-offs between different selection pressures, as well as plasticity across environmental conditions. Yet, studies on local adaptation are often performed under artificial conditions, leaving two issues unexplored: (i) how consistent are laboratory inferred local adaptations under natural conditions and (ii) how much phenotypic variation is attributed to phenotypic plasticity and to adaptive evolution, respectively, across environmental conditions? We reared fish from six locally adapted (domesticated and wild) populations of anadromous brown trout (Salmo trutta) in one semi-natural and three natural streams and recorded a key life-history trait (body size at the end of first growth season). We found that population-specific reaction norms were close to parallel across different streams and Q(ST) was similar - and larger than F-ST - within all streams, indicating a consistency of local adaptation in body size across natural environments. The amount of variation explained by population origin exceeded the variation across stream environments, indicating that genetic effects derived from adaptive processes have a stronger effect on phenotypic variation than plasticity induced by environmental conditions. These results suggest that plasticity does not swamp the phenotypic variation, and that selection may thus be efficient in generating genetic change.
|
|
| 2. |
- Rogell, Björn, 1979-, et al.
(author)
-
Genetic structure in peripheral populations of the natterjack toad, Bufo calamita, as revealed by AFLP
- 2010
-
In: Conservation Genetics. - : Springer Science and Business Media LLC. - 1566-0621 .- 1572-9737. ; 11:1, s. 173-181
-
Journal article (peer-reviewed)abstract
- Decreased fitness due to loss of genetic variation is a well recognised issue in conservation biology. Along the Swedish west coast, the endangered natterjack toad (Bufo calamita) occurs on, for the species, highly unusual habitat of rocky islands. Although the toads inhabit a restricted geographical area (maximum distance between the populations is 71 km), the fragmented nature of the landscape makes the genetic properties of the populations of conservation interest. However, lack of genetic variation found using conventional methods (microsatellites) has impeded genetic studies within these peripheral populations so far. In this study we assess population structure and genetic variation among seven of these fringe populations using 105 polymorphic Amplified Fragment Length Polymorphism (AFLP) loci. We found a well-defined population structure without evidence for isolation by distance, implying restricted gene flow between populations. Additionally, the populations differed in their amount of genetic variation, emphasizing the need to monitor genetically impoverished populations for possible declines mediated by inbreeding depression and reduced adaptive potential. Conservation implications for these unique populations are discussed in the light of our results.
|
|
| 3. |
- Rogell, Björn, et al.
(author)
-
Strong divergence in trait means but not in plasticity across hatchery and wild populations of sea-run brown trout Salmo trutta
- 2012
-
In: Molecular Ecology. - 0962-1083 .- 1365-294X. ; 21:12, s. 2963-2976
-
Journal article (peer-reviewed)abstract
- There is ample evidence that organisms adapt to their native environment when gene flow is restricted. However, evolution of plastic responses across discrete environments is less well examined. We studied divergence in means and plasticity across wild and hatchery populations of sea-run brown trout (Salmo trutta) in a common garden experiment with two rearing environments (hatchery and a nearly natural experimental stream). Since natural and hatchery environments differ, this arrangement provides an experiment in contemporary adaptation across the two environments. A QST - FST approach was used to investigate local adaptation in survival and growth over the first summer. We found evidence for divergent selection in survival in 1 year and in body length in both years and rearing environments. In general, the hatchery populations had higher survival and larger body size in both environments. QST in body size did not differ between the rearing environments, and constitutive divergence in the means was in all cases stronger than divergence in the plastic responses. These results suggest that in this system, constitutive changes in mean trait values are more important for local adaptation than increased plasticity. In addition, ex situ rearing conditions induce changes in trait means that are adaptive in the hatchery, but potentially harmful in the wild, suggesting that hatchery rearing is likely to be a suboptimal management strategy for trout populations facing selection in the stream environment.
|
|
