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In gynodioecious species, females and hermaphrodites coexist and the genetics of sex determination is usually nuclear cytoplasmic. Maintaining nuclear-cytoplasmic gynodioecy requires polymorphism for the feminizing genes (contained in the mitochondria) and the genes that restore male fertility (contained in the nucleus). This complex polymorphism depends, in part, on there being negative pleiotropic effects (i.e. costs) of the nuclear restorer alleles. Here, we combine information from theoretical studies and studies on the molecular action of restorer alleles in crops to interpret the probable costs of such alleles, and suggest how various aspects of the theoretical models could be tested. In doing so, we highlight how crops can be used to address evolutionary questions about the maintenance of nuclear-cytoplasmic gynodioecy.
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http://dx.doi.org/10.1016/j.tree.2006.09.013 | DOI Listing |
Oecologia
December 2017
Laboratory of Plant Conservation and Population Biology, KU Leuven, Kasteelpark Arenberg 31-bus 02435, 3001, Heverlee, Belgium.
In gynodioecious plant species, females can only persist when they have a reproductive advantage in comparison with hermaphrodites. However, several studies have shown that females do not necessarily produce more seeds than hermaphrodites, since seed production can be affected by population characteristics, such as female frequency or population size. The aim of this study was to quantify the female advantage across a large number of natural populations, examine its relationship with population sex ratio and size, and to assess the role of competition on the magnitude of the female advantage.
View Article and Find Full Text PDFEcol Evol
May 2015
Unité Evolution Ecologie Paléontologie, UMR CNRS 8198, Université de Lille 1 - Sciences et Technologies Villeneuve d'Ascq, France.
In gynodioecious plant species with nuclear-cytoplasmic sex determination, females and hermaphrodites plants can coexist whenever female have higher seed fitness than hermaphrodites. Although the effect of self fertilization on seed fitness in hermaphrodites has been considered theoretically, this effect is far from intuitive, because it can either increase the relative seed fitness of the females (if it leads hermaphrodites to produce inbred, low quality offspring) or decrease it (if it provides reproductive assurance to hermaphrodites). Hence, empirical investigation is needed to document whether relative seed fitness varies with whether pollen is or is not limiting to seed production.
View Article and Find Full Text PDFEvolution
September 2013
Laboratoire de Génétique et Evolution des Populations Végétales, UMR-CNRS 8198, Université des Sciences et Technologies de Lille - Lille 1, France.
Gynodioecy, the co-occurrence of females and hermaphrodites, is often due to conflicting interactions between cytoplasmic male sterility genes and nuclear restorers. Although gynodioecy often occurs in self-compatible species, the effect of self-pollination, inbreeding depression, and pollen limitation acting differently on females and hermaphrodites remains poorly known in the case of nuclear-cytoplasmic gynodioecy (NCG). In this study, we model NCG in an infinite population and we study the effect of selfing rate, inbreeding depression, and pollen limitation on the maintenance of gynodioecy and on sex ratios at equilibrium.
View Article and Find Full Text PDFNew Phytol
January 2014
Department of Ecology and Evolutionary Biology, University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS, 66045, USA.
Balancing selection refers to a variety of selective regimes that maintain advantageous genetic diversity within populations. We review the history of the ideas regarding the types of selection that maintain such polymorphism in flowering plants, notably heterozygote advantage, negative frequency-dependent selection, and spatial heterogeneity. One shared feature of these mechanisms is that whether an allele is beneficial or detrimental is conditional on its frequency in the population.
View Article and Find Full Text PDFHeredity (Edinb)
May 2011
Laboratoire Ecologie, Systématique et Evolution, UMR 8079 Univ Paris-Sud, Orsay, France.
Gynodioecy, the coexistence of female and hermaphrodite plants within a species, is often under nuclear-cytoplasmic sex determination, involving cytoplasmic male sterility (CMS) genes and nuclear restorers. A good knowledge of CMS and restorer polymorphism is essential for understanding the evolution and maintenance of gynodioecy, but reciprocal crossing studies remain scarce. Although mitochondrial diversity has been studied in a few gynodioecious species, the relationship between mitotype diversity and CMS status is poorly known.
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