Recombination and loss of complementation: a more than two-fold cost for parthenogenesis. J Evol Biol

Département de Biologie, Section Ecologie et Evolution, Université de Fribourg, Fribourg, Switzerland.
Journal of Evolutionary Biology (Impact Factor: 3.23). 10/2004; 17(5):1084-97. DOI: 10.1111/j.1420-9101.2004.00745.x
Source: PubMed


Certain types of asexual reproduction lead to loss of complementation, that is unmasking of recessive deleterious alleles. A theoretical measure of this loss is calculated for apomixis, automixis and endomitosis in the cases of diploidy and polyploidy. The effect of the consequent unmasking of deleterious recessive mutations on fitness is also calculated. Results show that, depending on the number of lethal equivalents and on the frequency of recombination, the cost produced by loss of complementation after few generations of asexual reproduction may be greater than the two-fold cost of meiosis. Maintaining complementation may, therefore, provide a general short-term advantage for sexual reproduction. Apomixis can replace sexual reproduction under a wide range of parameters only if it is associated with triploidy or tetraploidy, which is consistent with our knowledge of the distribution of apomixis.

8 Reads
  • Source
    • "Moreover, shifts from sexual to asexual reproduction are often associated with changes in life history and/or functional or evolutionary constraints that could influence the relative fitness of sexual and asexual individuals (Engelstadter, 2008; Horandl, 2009b; Lehtonen et al., 2012). For instance, whereas apomixis (thelytoky with no meiosis) maintains the level of heterozygosity, some forms of automixis (meiosis followed by the restoration of diploidy) reduce it (Suomalainen et al., 1987) and thus could lower the fitness of asexuals by exposing them to recessive deleterious alleles (Archetti, 2005; Engelstadter, 2008). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The evolutionary paradox of sex remains one of the major debates in evolutionary biology. The study of species capable of both sexual and asexual reproduction can elucidate factors important in the evolution of sex. One such species is the ant Cataglyphis cursor, where the queen maximizes the transmission of her genes by producing new queens (gynes) asexually while simultaneously maintaining a genetically diverse workforce via the sexual production of workers. We show that the queen can also produce gynes sexually and may do so to offset the costs of asexual reproduction. We genotyped 235 gynes from 18 colonies and found that half were sexually produced. A few colonies contained both sexually and asexually produced gynes. Although workers in this species can also use thelytoky, we found no evidence of worker production of gynes based on genotypes of 471 workers from the six colonies producing sexual gynes. Gynes are thus mainly, and potentially exclusively, produced by the queen. Simulations of gynes inbreeding level following one to ten generations of automictic thelytoky suggest that the queen switches between or combines thelytoky and sex, which may reduce the costs of inbreeding. This is supported by the relatively small size of inbred gynes in one colony, although we found no relationship between the level of inbreeding and immune parameters. Such facultative use of sex and thelytoky by individual queens contrasts with other known forms of parthenogenesis in ants, which are typically characterized by distinct lineages specializing in one strategy or the other.
    Journal of Evolutionary Biology 05/2013; 26(6):1431-1444. DOI:10.1111/jeb.12142 · 3.23 Impact Factor
  • Source
    • "animals (Suomalainen et al. 2000; Simon et al. 2003; Kearney 2005) are polyploid, and various causal mechanisms for this link have been proposed (Archetti 2004; Whitton et al. 2008). Although asexuality is commonly viewed as heightening long-term extinction risk, the effects of polyploidy on lineage potential are less clear. "
    [Show abstract] [Hide abstract]
    ABSTRACT: A life-history transition to asexuality is typically viewed as leading to a heightened extinction risk, and a number of studies have evaluated this claim by examining the relative ages of asexual versus closely related sexual lineages. Surprisingly, a rigorous assessment of the age of an asexual plant lineage has never been published, although asexuality is extraordinarily common among plants. Here, we estimate the ages of sexual diploids and asexual polyploids in the fern genus Astrolepis using a well-supported plastid phylogeny and a relaxed-clock dating approach. The 50 asexual polyploid samples we included were conservatively estimated to comprise 19 distinct lineages, including a variety of auto- and allopolyploid genomic combinations. All were either the same age or younger than the crown group comprising their maternal sexual-diploid parents based simply on their phylogenetic position. Node ages estimated with the relaxed-clock approach indicated that the average maximum age of asexual lineages was 0.4 My, and individual lineages were on average 7 to 47 times younger than the crown- and total-ages of their sexual parents. Although the confounding association between asexuality and polyploidy precludes definite conclusions regarding the effect of asexuality, our results suggest that asexuality limits evolutionary potential in Astrolepis.
    Evolution 11/2011; 65(11):3217-29. DOI:10.1111/j.1558-5646.2011.01362.x · 4.61 Impact Factor
  • Source
    • "Recombination is further constrained during male meiosis in apomicts in the chromosomal region transmitting the trait to progeny [18,19]. The fundamental importance of recombination and the paradox of sex [20,21] have inspired interest in deciphering the evolution of asexual organisms [14,22]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Apomixis is an intriguing trait in plants that results in maternal clones through seed reproduction. Apomixis is an elusive, but potentially revolutionary, trait for plant breeding and hybrid seed production. Recent studies arguing that apomicts are not evolutionary dead ends have generated further interest in the evolution of asexual flowering plants. In the present study, we investigate karyotypic variation in a single chromosome responsible for transmitting apomixis, the Apospory-Specific Genomic Region carrier chromosome, in relation to species phylogeny in the genera Pennisetum and Cenchrus. A 1 kb region from the 3' end of the ndhF gene and a 900 bp region from trnL-F were sequenced from 12 apomictic and eight sexual species in the genus Pennisetum and allied genus Cenchrus. An 800 bp region from the Apospory-Specific Genomic Region also was sequenced from the 12 apomicts. Molecular cytological analysis was conducted in sixteen Pennisetum and two Cenchrus species. Our results indicate that the Apospory-Specific Genomic Region is shared by all apomictic species while it is absent from all sexual species or cytotypes. Contrary to our previous observations in Pennisetum squamulatum and Cenchrus ciliaris, retrotransposon sequences of the Opie-2-like family were not closely associated with the Apospory-Specific Genomic Region in all apomictic species, suggesting that they may have been accumulated after the Apospory-Specific Genomic Region originated. Given that phylogenetic analysis merged Cenchrus and newly investigated Pennisetum species into a single clade containing a terminal cluster of Cenchrus apomicts, the presumed monophyletic origin of Cenchrus is supported. The Apospory-Specific Genomic Region likely preceded speciation in Cenchrus and its lateral transfer through hybridization and subsequent chromosome repatterning may have contributed to further speciation in the two genera.
    BMC Evolutionary Biology 10/2011; 11(1):289. DOI:10.1186/1471-2148-11-289 · 3.37 Impact Factor
Show more

Preview (2 Sources)

8 Reads
Available from