Evolutionary potential in the wild: more than meets the eye
ABSTRACT The genus Aquilegia consists of 60-70 perennial plant species widely distributed throughout the northern hemisphere. Its flowers have a delicate and ornamental appearance that makes them a favourite of gardeners. In this genus, adaptive radiations for both floral and vegetative traits have occurred. These adaptive radiations, and the key phylogenetic placement of Aquilegia between Arabidopsis and rice, make this genus a 'model system' for plant evolution (Kramer 2009). In this issue, Castellanos et al. (2011) use a marker-based method to infer heritability for floral and vegetative traits in two Aquilegia species. Layered on top of this are estimates of the strength of natural selection. This novel joint estimation of heritability and selection in the wild showed that vegetative traits, compared to floral traits, have the highest evolutionarily potential. Evolutionary potential is the most important quantity to measure in wild populations. It combines inheritance and strength of selection and predicts the potential for populations to adapt to changing environments. The combination of molecular techniques with species in natural environments makes this work a model for molecular ecological investigations.
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ABSTRACT: A major barrier to evolutionary studies of sex determination and sex chromosomes has been a lack of information on the types of sex-determining mechanisms that occur among different species. This is particularly problematic in groups where most species lack visually heteromorphic sex chromosomes, such as fish, amphibians and reptiles, because cytogenetic analyses will fail to identify the sex chromosomes in these species. We describe the use of restriction site associated DNA (RAD) sequencing, or RAD-seq, to identify sex-specific molecular markers and subsequently determine whether a species has male or female heterogamety. To test the accuracy of this technique we examined the lizard Anolis carolinensis. We performed RAD-seq on seven male and ten female A. carolinensis and found one male-specific molecular marker. Anolis carolinensis has previously been shown to possess male heterogamety and the recently published A. carolinensis genome facilitated characterization of the sex-specific RAD-seq marker. We validated the male specificity of the new marker using PCR on additional individuals and also found that it is conserved in some other Anolis species. We discuss the utility of using RAD-seq to identify sex determining mechanisms in other species with cryptic or homomorphic sex chromosomes and the implications for the evolution of male heterogamety in Anolis. This article is protected by copyright. All rights reserved.Molecular Ecology Resources 02/2014; 14(5). DOI:10.1111/1755-0998.12237 · 5.63 Impact Factor
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ABSTRACT: BACKGROUND: The remarkable diversity of mating patterns and sexual systems in flowering plants has fascinated evolutionary biologists for more than a century. Enduring questions about this topic include why sexual polymorphisms have evolved independently in over 100 plant families, and why proportions of self- and cross-fertilization often vary dramatically within and among populations. Important new insights concerning the evolutionary dynamics of plant mating systems have built upon a strong foundation of theoretical models and innovative field and laboratory experiments. However, as the pace of advancement in this field has accelerated, it has become increasingly difficult for researchers to follow developments outside their primary area of research expertise. SCOPE: In this Viewpoint paper we highlight three important themes that span and integrate different subdisciplines: the changes in morphology, phenology, and physiology that accompany the transition to selfing; the evolutionary consequences of pollen pool diversity in flowering plants; and the evolutionary dynamics of sexual polymorphisms. We also highlight recent developments in molecular techniques that will facilitate more efficient and cost-effective study of mating patterns in large natural populations, research on the dynamics of pollen transport, and investigations on the genetic basis of sexual polymorphisms. This Viewpoint also serves as the introduction to a Special Issue on the Evolution of Plant Mating Systems. The 15 papers in this special issue provide inspiring examples of recent discoveries, and glimpses of exciting developments yet to come.Annals of Botany 12/2011; 109(3):493-503. DOI:10.1093/aob/mcr319 · 3.30 Impact Factor