Article

Rates of Molecular Evolution Are Linked to Life History in Flowering Plants

Department of Ecology and Evolutionary Biology, 21 Sachem Street, Post Office Box 208105, Yale University, New Haven, CT 06520-8105, USA.
Science (Impact Factor: 33.61). 11/2008; 322(5898):86-9. DOI: 10.1126/science.1163197
Source: PubMed

ABSTRACT

Variable rates of molecular evolution have been documented across the tree of life, but the cause of this observed variation within and among clades remains uncertain. In plants, it has been suggested that life history traits are correlated with the rate of molecular evolution, but previous studies have yielded conflicting results. Exceptionally large phylogenies of five major angiosperm clades demonstrate that rates of molecular evolution are consistently low in trees and shrubs, with relatively long generation times, as compared with related herbaceous plants, which generally have shorter generation times. Herbs show much higher rates of molecular change but also much higher variance in rates. Correlates of life history attributes have long been of interest to biologists, and our results demonstrate how changes in the rate of molecular evolution that are linked to life history traits can affect measurements of the tempo of evolution as well as our ability to identify and conserve biodiversity.

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    • "If, in addition, the spontaneous mutation rate on the molecular level itself depends on ambient temperatures, then the probability and rate of evolutionary processes that involve mutations would further increase with a higher thermal regime. Strong support for the correlation of molecular evolution with generation time comes from comparative studies on vertebrates, plants and invertebrates89101112. However, these studies do not include temperature as a putative environmental driver of this correlation. "
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    ABSTRACT: The evolutionary speed hypothesis (ESH) proposes a causal mechanism for the latitudinal diversity gradient. The central idea of the ESH is that warmer temperatures lead to shorter generation times and increased mutation rates. On an absolute timescale, both should lead to an acceleration of selection and drift. Based on the ESH, we developed predictions regarding the distribution of intraspecific genetic diversity: populations of ectothermic species with more generations per year owing to warmer ambient temperatures should be more differentiated from each other, accumulate more mutations and show evidence for increased mutation rates compared with populations in colder regions.We used the multivoltine insect species Chironomus riparius to test these predictions with cytochrome oxidase I (COI) sequence data and found that populations from warmer regions are indeed significantly more differentiated and have significantly more derived haplotypes than populations from colder regions. We also found a significant correlation of the annual mean temperature with the population mutation parameter θ that serves as a proxy for the per generation mutation rate under certain assumptions. This pattern could be corroborated with two nuclear loci. Overall, our results support the ESH and indicate that the thermal regime experienced may be crucially driving the evolution of ectotherms and may thus ultimately govern their speciation rate.
    No preview · Article · Mar 2016 · Proceedings of the Royal Society B: Biological Sciences
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    • "Although the generation time effect on molecular evolution in plants has been under debate (e.g. Whittle and Johnston 2003; Verdú et al. 2007; Soria-Hernanz et al. 2008), in the last few years, some robust analyses of the phylogenies of numerous lineages have undoubtedly shown higher rates of molecular changes associated with shorter generation times (Smith and Donoghue 2008; Müller and Albach 2010; Yue et al. 2010). With ca. "
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    • "These results are unlikely to be due to the statistical errors of our method, because the estimated type I error is around 0.05 and the power is up to 80% for the mitochondrial results and the regression coefficients are consistently negative. The copy-frequency effect is a good explanation for many observed patterns in rate of molecular evolution, such as the widespread observation of a generation time effect (e.g., Mooers and Harvey 1994; Bromham et al. 1996; Smith and Donoghue 2008; Thomas et al. 2010), higher rates of molecular evolution in highly eusocial hymenopterans (Bromham and Leys 2005), faster rates of molecular evolution in shorter plants (Lanfear, Ho, et al. 2013; Bromham et al. 2015), and faster mutations in sequences that are carried more often in male germline than in female germline (Ellegren and Fridolfsson 1997; Whittle and Johnston 2002). So why do we not find evidence that the copy-frequency effect is a primary driver of differences in mutation rates between rockfish species? "
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