Genetic Models of Adaptation and Gene Flow in Peripheral Populations

Garcı́a-Ramos, Gisela; Kirkpatrick, Mark

doi:10.2307/2410956

Cited by 397 publications

(434 citation statements)

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“…Island populations of tortoises (Caccone et al 2002), beetles (Finston & Peck 1995) and lizards (Wright 1983) in the Galápagos, and Drosophila (Desalle 1995), spiders (Hormiga et al 2003) and crickets (Shaw 2002) in Hawaii tend to be genetically more closely related if they occur on neighbouring islands. The abundant evidence from nature has led to the assumption of distance-limited dispersal in models of island biogeography (MacArthur & Wilson 1967), geographical clines (Endler 1977;Kirkpatrick & Barton 1997), metapopulation dynamics (Hanski & Gilpin 1997) and speciation (Mayr 1942;Garcia-Ramos & Kirkpatrick 1997).…”

Section: Introductionmentioning

confidence: 99%

Habitat selection and ecological speciation in Galápagos warbler finches ( Certhidea olivacea and Certhidea fusca )

Tonnis

Grant

et al. 2005

Proc. R. Soc. B.

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We investigated phylogeographic divergence among populations of Galápagos warbler finches. Their broad distribution, lack of phenotypic differentiation and low levels of genetic divergence make warbler finches an appropriate model to study speciation in allopatry. A positive relationship between genetic and geographical distances is expected for island taxa. Warbler finches actually showed a negative isolation by distance relationship, causing us to reject the hypothesis of distance-limited dispersal. An alternative hypothesis, that dispersal is limited by habitat similarity, was supported. We found a positive correlation between genetic distances and differences in maximum elevation among islands, which is an indicator of ecological similarity. MtDNA sequence variation revealed monophyletic support for two distinct species. Certhidea olivacea have recently dispersed among larger central islands, while some Certhidea fusca have recently dispersed to small islands at opposite ends of the archipelago. We conclude that females have chosen to breed on islands with habitats similar to their natal environment. Habitat selection is implicated as an important component of speciation of warbler finches, which is the earliest known divergence of the adaptive radiation of Darwin's finches. These results suggest that small populations can harbour cryptic but biologically meaningful variation that may affect longer term evolutionary processes.

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Section: Introductionmentioning

confidence: 99%

Habitat selection and ecological speciation in Galápagos warbler finches ( Certhidea olivacea and Certhidea fusca )

Tonnis

Grant

et al. 2005

Proc. R. Soc. B.

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“…The evolution and ecology of peripheral populations are driven by various genetic and demographic processes. For example, adaptation to local conditions depends greatly on the level of gene flow from the core population (García-Ramos and Kirkpatrick 1997;Lenormand 2002). Although it is generally acknowledged that low gene flow facilitates rapid divergence at a range margin (Felsenstein 1976;Slatkin 1985;García-Ramos and Kirkpatrick 1997), gene flow can play ambiguous roles in adaptation to local conditions, depending on additional factors.…”

Section: Introductionmentioning

confidence: 99%

“…For example, adaptation to local conditions depends greatly on the level of gene flow from the core population (García-Ramos and Kirkpatrick 1997;Lenormand 2002). Although it is generally acknowledged that low gene flow facilitates rapid divergence at a range margin (Felsenstein 1976;Slatkin 1985;García-Ramos and Kirkpatrick 1997), gene flow can play ambiguous roles in adaptation to local conditions, depending on additional factors. If a peripheral population is isolated from the core population, it may never adapt to local conditions because of genetic drift and low mutational input that causes deficiency of beneficial mutations (Kawecki 2000;Bridle and Vines 2006).…”

Section: Introductionmentioning

confidence: 99%

“…This may be especially the case when a peripheral population is characterised by low genetic variation, for example due to the founder effect (Pujol and Pannell 2008). On the other hand, gene flow can lead to migration load when the local optimum phenotypic value differs from the average for the core population (García-Ramos and Kirkpatrick 1997;Bolnick and Nosil 2007). As a result, peripheral populations can be subjected to continuous directional selection, being however unable to reach the ecological optimum.…”

Section: Introductionmentioning

confidence: 99%

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Genetic evidence of reproductive isolation in a remote enclave of Quercus pubescens in the presence of cross-fertile species

et al. 2012

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Peripheral populations may be crucial for understanding processes underlying adaptive genetic variation. Their evolution and ecology are driven by various genetic and demographic processes, such as selection, gene flow and bottleneck. Peripheral populations often experience a reduction in density resulting in the Allee effect. The presence of interfertile species increases the opportunity for hybridisation, which allows for a rescue from the Allee effect, but at the risk of genetic extinction through introgression. In this article we investigated a peripheral population of Quercus pubescens, a European tree species. The study population is located in Poland, several hundred kilometres northwards from the main species range. Due to geographic separation, the study population exists under strong pressure of introgression from potentially inter-fertile Q. petraea and Q. robur, which are the only common oaks in Poland. The intermediate morphology between typical Q. pubescens and a common oak species found in the study population supports the introgression hypothesis, which could be in line with the earlier studies of this species complex conducted in the main range of Q. pubescens. Alternatively, the intermediate morphology could reflect the founder effect or selection at an ecological extreme. We attempted to verify these hypotheses using microsatellites and a reference of common oak species. The results showed that the study population is genetically distinct from both Q. petraea and Q. robur. Additionally, the population is characterised by a low effective population size and limited gene dispersal. This suggests that the study population reveals strong reproductive isolation from common species, implying alternative sources of atypical morphology.

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“…Additionally, the more homogenous environments of oceanic fishes compared to estuarine fishes may result in weaker environmental selection pressures, also making spatial adaptations less likely. If oceanic species tend to lack genetic structure, they may be limited in their ability to respond to climate change, since populations may not be able to respond differently across their range (Garcia-Ramos & Kirkpatrick 1997, Lenormand 2002.…”

Section: Introductionmentioning

confidence: 99%

Absence of countergradient and cogradient variation in an oceanic silverside, the California grunion Leuresthes tenuis

Brown¹,

Baumann²,

Conover³

2012

Mar. Ecol. Prog. Ser.

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Spatial adaptations that maximize a species' fitness in its local environment, particularly in the form of countergradient variation (CnGV = genotypic influences counteract environmental effects on trait variation) and cogradient variation (CoGV = genotypic influences accentuate environmental plasticity), have been documented in many estuarine and anadromous fishes. However, their prevalence in more oceanic fishes, where extensive gene flow and reduced environmental selection may preclude local adaptation, remains unclear. If oceanic species lack genetic structure, they may be limited in their ability to adapt to global climate change. We examined the potential for adaptation in oceanic fishes by testing whether an oceanic silverside, the California grunion Leuresthes tenuis, displays CnGV in growth capacity and CoGV in vertebral number across a latitudinal gradient as found in estuarine silversides. Common garden experiments revealed that reaction norms for growth in response to temperature differed little among 3 L. tenuis populations from different latitudes. Growth rates of wild adult L. tenuis measured from scale analysis suggested that growth may be slightly faster at more southern latitudes, likely due to environmental variation. Mean vertebral number in wild L. tenuis, determined from radiographs, were nearly identical for all populations. Overall, our results did not provide evidence for spatial adaptations in these traits of L. tenuis, in contrast to the strong patterns of latitudinal trait adaptation in other, more estuarine silversides. This study provides support for the finding that higher gene flow levels and weaker environmental selection pressures of oceanic species limit local adaptation.

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Genetic Models of Adaptation and Gene Flow in Peripheral Populations

Cited by 397 publications

References 0 publications

Habitat selection and ecological speciation in Galápagos warbler finches ( Certhidea olivacea and Certhidea fusca )

Habitat selection and ecological speciation in Galápagos warbler finches ( Certhidea olivacea and Certhidea fusca )

Genetic evidence of reproductive isolation in a remote enclave of Quercus pubescens in the presence of cross-fertile species

Absence of countergradient and cogradient variation in an oceanic silverside, the California grunion Leuresthes tenuis

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