Speciation rates are unrelated to the formation of population structure in Malagasy gemsnakes

Burbrink, Frank T.; Ruane, Sara; Rabibisoa, Nirhy; Raselimanana, Achille P.; Raxworthy, Christopher J.; Kuhn, Arianna

doi:10.1002/ece3.10344

Cited by 5 publications

(1 citation statement)

References 75 publications

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“…We however expect to find a correlation between macroevolutionary speciation rates and the rate of population formation, which reflects speciation initiation. This is indeed what was found by Harvey et al 2019; the lack of correlation in other studies (Singhal, Colli, et al 2022; Singhal, Huang, et al 2018; Burbrink et al 2023) may reflect cases when speciation is modulated by the rate of population extinction rather than by the rate of speciation initiation, as expected if the initiation rate is high and/or the population extinction rate is low.…”

Section: Discussionsupporting

confidence: 80%

A theoretical framework linking the birth-death and protracted birth-death models, with implications for the phylogenetic analysis of diversification

Veron,

Andréoletti,

Giraud

et al. 2024

Preprint

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While speciation takes time, standard birth-death processes used to infer diversification from phylogenies assume that it is instantaneous. This limits the interpretation of phylogenetic estimates of speciation and extinction rates, and our understanding of the microevolutionary processes that modulate these rates. Here, we consider the protracted birth-death model, which accounts for the fact that speciation takes time. We compute an “equivalent” standard birth-death process, of which diversification dynamics approximate those induced by the protracted process. We find that the equivalent birth rate declines close to the present, and that the duration of speciation influences when this decays occurs more than the equivalent rates themselves. The equivalent rates are relatively constant in the past. The birth rate in the past scales with the rate at which speciation is initiated, with a scaling factor that depends mostly on the population extinction rate. Our results suggest that the rates of speciation initiation and population extinction may often play a larger role than the speed at which populations acquire reproductive isolation in modulating speciation rates. Our study establishes a theoretical framework for understanding how microevolutionary processes combine to explain the diversification of species groups on macroevolutionary time scales.

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Section: Discussionsupporting

confidence: 80%

A theoretical framework linking the birth-death and protracted birth-death models, with implications for the phylogenetic analysis of diversification

Veron,

Andréoletti,

Giraud

et al. 2024

Preprint

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Variable success in linking micro- and macroevolution

Schluter

2024

Evolutionary Journal of the Linnean Society

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Attempts to predict macroevolution from microevolution, and microevolution from macroevolution, when natural selection is the main cause have met with varying success. Explanations for failure are numerous, but the reasons are uncertain even when a link is found. Here, I discuss possible explanations for outcomes of three efforts and ways to test them. First, quantitative genetic variation within populations often predicts directions of species divergence with surprising accuracy. Natural selection likely contributes to this pattern, but the evidence suggests that even long-term phenotypic evolution is influenced by enduring genetic biases. Second, the rate of evolution of reproductive isolation repeatedly fails to predict species diversification rates for unknown reasons. Suspicion falls on the influence of ecological and population demographic processes that might play a dominant role in the net rate of accumulation of species, an idea as yet little tested. Third, macroevolutionary patterns in the distribution of phenotypes of species in clades can in principle predict selection coefficients in diverging populations. I use the concept of adaptive landscape to suggest why the macroevolutionary signal of divergent selection is strongest at the time of splitting and why little information about selection coefficients from phylogenetic methods remains in the long run. Estimating adaptive landscapes from first principles would facilitate further efforts to link microevolution and macroevolution

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Discerning structure versus speciation in phylogeographic analysis of Seepage Salamanders (Desmognathus aeneus) using demography, environment, geography, and phenotype

Pyron,

Kakkera,

Beamer

et al. 2023

Molecular Ecology

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Numerous mechanisms can drive speciation, including isolation by adaptation, distance, and environment. These forces can promote genetic and phenotypic differentiation of local populations, the formation of phylogeographic lineages, and ultimately, completed speciation. However, conceptually similar mechanisms may also result in stabilizing rather than diversifying selection, leading to lineage integration and the long‐term persistence of population structure within genetically cohesive species. Processes that drive the formation and maintenance of geographic genetic diversity while facilitating high rates of migration and limiting phenotypic differentiation may thereby result in population genetic structure that is not accompanied by reproductive isolation. We suggest that this framework can be applied more broadly to address the classic dilemma of “structure” versus “species” when evaluating phylogeographic diversity, unifying population genetics, species delimitation, and the underlying study of speciation. We demonstrate one such instance in the Seepage Salamander (Desmognathus aeneus) from the southeastern United States. Recent studies estimated up to 6.3% mitochondrial divergence and four phylogenomic lineages with broad admixture across geographic hybrid zones, which could potentially represent distinct species supported by our species‐delimitation analyses. However, while limited dispersal promotes substantial isolation by distance, microhabitat specificity appears to yield stabilizing selection on a single, uniform, ecologically mediated phenotype. As a result, climatic cycles promote recurrent contact between lineages and repeated instances of high migration through time. Subsequent hybridization is apparently not counteracted by adaptive differentiation limiting introgression, leaving a single unified species with deeply divergent phylogeographic lineages that nonetheless do not appear to represent incipient species.

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Speciation rates are unrelated to the formation of population structure in Malagasy gemsnakes

Cited by 5 publications

References 75 publications

A theoretical framework linking the birth-death and protracted birth-death models, with implications for the phylogenetic analysis of diversification

A theoretical framework linking the birth-death and protracted birth-death models, with implications for the phylogenetic analysis of diversification

Variable success in linking micro- and macroevolution

Discerning structure versus speciation in phylogeographic analysis of Seepage Salamanders (Desmognathus aeneus) using demography, environment, geography, and phenotype

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