Large body size in an island‐dwelling bird: a microevolutionary analysis

Frentiu, Francesca D.; Clegg, Sonya M.; Blows, Mark W.; Owens, Ian P. F.

doi:10.1111/j.1420-9101.2006.01242.x

Cited by 17 publications

(26 citation statements)

References 81 publications

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“…(a) Study population and morphological measurements The individuals used in this study (NZ479) were the same as those described in a previous study of this population ( Frentiu et al 2007). Briefly, measurements and samples were taken from nestlings in the Heron Island population of Capricorn silvereyes over three consecutive breeding seasons: 2000-2001, 2001-2002 and 2003-2004.…”

Section: Methodsmentioning

confidence: 99%

“…The presence of such full siblings was anticipated to be helpful because it would allow us to check the power of our molecular markers in identifying close relatives. As part of a long-term study of evolutionary genetics in this population, we also conducted reciprocal cross-foster manipulations in which one or two chicks were swapped between pairs of nests and this design was used to implement the traditional animal model (see Frentiu et al 2007).…”

Section: Methodsmentioning

confidence: 99%

“…In addition, we have a dataset that consists of individuals used in a cross-fostering experiment ( Frentiu et al 2007), minimizing the extent to which the effect of shared genes is inflated by the effect of shared environments. Finally, the quantitative genetic basis of morphology in this population of birds is of intrinsic interest because it is an example of an unusually large island race that shows the characteristic pattern for insular passerines (Clegg & Owens 2002), having evolved to be approximately 40% larger than its mainland counterpart in just 4000 years (Clegg et al 2002a,b;Robinson-Wolrath & Owens 2003;Scott et al 2003;Frentiu et al 2007).…”

Section: Introductionmentioning

confidence: 99%

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Pedigree-free animal models: the relatedness matrix reloaded

et al. 2008

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Animal models typically require a known genetic pedigree to estimate quantitative genetic parameters. Here we test whether animal models can alternatively be based on estimates of relatedness derived entirely from molecular marker data. Our case study is the morphology of a wild bird population, for which we report estimates of the genetic variance-covariance matrices (G ) of six morphological traits using three methods: the traditional animal model; a molecular marker-based approach to estimate heritability based on Ritland's pairwise regression method; and a new approach using a molecular genealogy arranged in a relatedness matrix (R) to replace the pedigree in an animal model. Using the traditional animal model, we found significant genetic variance for all six traits and positive genetic covariance among traits. The pairwise regression method did not return reliable estimates of quantitative genetic parameters in this population, with estimates of genetic variance and covariance typically being very small or negative. In contrast, we found mixed evidence for the use of the pedigree-free animal model. Similar to the pairwise regression method, the pedigree-free approach performed poorly when the full-rank R matrix based on the molecular genealogy was employed. However, performance improved substantially when we reduced the dimensionality of the R matrix in order to maximize the signal to noise ratio. Using reduced-rank R matrices generated estimates of genetic variance that were much closer to those from the traditional model. Nevertheless, this method was less reliable at estimating covariances, which were often estimated to be negative. Taken together, these results suggest that pedigree-free animal models can recover quantitative genetic information, although the signal remains relatively weak. It remains to be determined whether this problem can be overcome by the use of a more powerful battery of molecular markers and improved methods for reconstructing genealogies.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Pedigree-free animal models: the relatedness matrix reloaded

et al. 2008

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“…In these analyses, we assumed a range of heritabilities (0.1-0.5) although those presented here are based on previous studies of birds (Price and Burley 1993;Merila et al 2001;Hadfield et al 2006;Frentiu et al 2007). Only the heritability estimate for bill color (Price and Burley 1993) is based on data from the zebra finch.…”

Section: Zebra Finch Samplesmentioning

confidence: 99%

“…Two estimates of N e * are provided using the 95% high and low bounds of the estimate of divergence time (t) from IM. Heritability estimates (h 2 ) are based on previous studies (Price and Burley 1993;Merila et al 2001;Hadfield et al 2006;Frentiu et al 2007). N e * estimates in italics represent cases where N e * .…”

Section: à6mentioning

confidence: 99%

Nucleotide Variation, Linkage Disequilibrium and Founder-Facilitated Speciation in Wild Populations of the Zebra Finch (Taeniopygia guttata)

2009

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The zebra finch has long been an important model system for the study of vocal learning, vocal production, and behavior. With the imminent sequencing of its genome, the zebra finch is now poised to become a model system for population genetics. Using a panel of 30 noncoding loci, we characterized patterns of polymorphism and divergence among wild zebra finch populations. Continental Australian populations displayed little population structure, exceptionally high levels of nucleotide diversity (p ¼ 0.010), a rapid decay of linkage disequilibrium (LD), and a high population recombination rate (r % 0.05), all of which suggest an open and fluid genomic background that could facilitate adaptive variation. By contrast, substantial divergence between the Australian and Lesser Sunda Island populations (K ST ¼ 0.193), reduced genetic diversity (p ¼ 0.002), and higher levels of LD in the island population suggest a strong but relatively recent founder event, which may have contributed to speciation between these populations as envisioned under founder-effect speciation models. Consistent with this hypothesis, we find that under a simple quantitative genetic model both drift and selection could have contributed to the observed divergence in six quantitative traits. In both Australian and Lesser Sundas populations, diversity in Z-linked loci was significantly lower than in autosomal loci. Our analysis provides a quantitative framework for studying the role of selection and drift in shaping patterns of molecular evolution in the zebra finch genome.

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Rapid morphological divergence following a human-mediated introduction: the role of drift and directional selection

2020

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Theory predicts that when populations are established by few individuals, random founder effects can facilitate rapid phenotypic divergence even in the absence of selective processes. However, empirical evidence from historically documented colonisations suggest that, in most cases, drift alone is not sufficient to explain the rate of morphological divergence. Here, using the human-mediated introduction of the silvereye (Zosterops lateralis) to French Polynesia, which represents a potentially extreme example of population founding, we reassess the potential for morphological shifts to arise via drift alone. Despite only 80 years of separation from their New Zealand ancestors, French Polynesian silvereyes displayed significant changes in body and bill size and shape, most of which could be accounted for by drift, without the need to invoke selection. However, signatures of selection at genes previously identified as candidates for bill size and body shape differences in a range of bird species, also suggests a role for selective processes in driving morphological shifts within this population. Twenty-four SNPs in our RAD-Seq dataset were also found to be strongly associated with phenotypic variation. Hence, even under population founding extremes, when it is difficult to reject drift as the sole mechanism based on rate tests of phenotypic shifts, the additional role of divergent natural selection in novel environments can be revealed at the level of the genome.

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Large body size in an island‐dwelling bird: a microevolutionary analysis

Cited by 17 publications

References 81 publications

Pedigree-free animal models: the relatedness matrix reloaded

Pedigree-free animal models: the relatedness matrix reloaded

Nucleotide Variation, Linkage Disequilibrium and Founder-Facilitated Speciation in Wild Populations of the Zebra Finch (Taeniopygia guttata)

Rapid morphological divergence following a human-mediated introduction: the role of drift and directional selection

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