Correlated Evolution of Sexual System and Life-History Traits in Mosses

Crawford, Monique; Jesson, Linley K.; Garnock‐Jones, P. J.

doi:10.1111/j.1558-5646.2009.00615.x

Cited by 64 publications

(75 citation statements)

References 92 publications

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“…In bryophytes, chromosomal sex determination has been reported by several studies, which hypothesized that bisexuality is linked to polyploidy (Crawford et al, 2009). Indeed, if sex determination in bryophytes is chromosomal (reviewed in McDaniel & Perroud, 2012), then the X and Y chromosomes in the sporophyte segregate at meiosis to give female gametophytes bearing an X and males bearing a Y chromosome.…”

Section: Discussionmentioning

confidence: 99%

Increased diversification rates follow shifts to bisexuality in liverworts

et al. 2016

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SummaryShifts in sexual systems are one of the key drivers of species diversification. In contrast to angiosperms, unisexuality prevails in bryophytes. Here, we test the hypotheses that bisexuality evolved from an ancestral unisexual condition and is a key innovation in liverworts.We investigate whether shifts in sexual systems influence diversification using hidden state speciation and extinction analysis (HiSSE). This new method compares the effects of the variable of interest to the best-fitting latent variable, yielding robust and conservative tests.We find that the transitions in sexual systems are significantly biased toward unisexuality, even though bisexuality is coupled with increased diversification. Sexual systems are strongly conserved deep within the liverwort tree but become much more labile toward the present.Bisexuality appears to be a key innovation in liverworts. Its effects on diversification are presumably mediated by the interplay of high fertilization rates, massive spore production and long-distance dispersal, which may separately or together have facilitated liverwort speciation, suppressed their extinction, or both. Importantly, shifts in liverwort sexual systems have the opposite effect when compared to angiosperms, leading to contrasting diversification patterns between the two groups. The high prevalence of unisexuality among liverworts suggests, however, a strong selection for sexual dimorphism.

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Section: Discussionmentioning

confidence: 99%

Increased diversification rates follow shifts to bisexuality in liverworts

et al. 2016

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“…However, the forces driving the evolution of sexual systems may differ among taxa. Phylogenetically controlled tests have identified the environmental factors responsible for the evolution of different sexual systems in other taxa, especially plants [41,51]. Few tests exist in animal taxa with diverse sexual systems comparable to those of barnacles [33], and the evolution of such systems in most cases remains to be clarified.…”

Section: Discussionmentioning

confidence: 99%

“…Since the ML tree contained several polytomies, 100 trees with randomly resolved polytomies were created using MESQUITE v. 2.71 [44] with branch lengths of 0.0001 [41,45]. The 100 trees gave very similar log-likelihoods, in the case of both the unrestricted (i.e.…”

Section: (A) Sexual Systemsmentioning

confidence: 99%

“…Since BAYESTRAITS cannot treat polytomies (three or more unresolved branches from a common ancestor), the trees were re-rooted with both Ibla quadrivalvis and Ibla cumingi (Iblomorpha) always designated as the outgroup. The presence (1) and absence (0) of dwarf males and females were both treated as continuous variables [41] since the explanatory variable (the proportion of solitary individuals) was also continuous (BAYESTRAITS does not allow mixture of continuous and discrete variables). Their relationships were analysed using the Continuous module in BAYESTRAITS (http://www.evolution.rdg.ac.uk/BayesTraits.…”

Section: (A) Sexual Systemsmentioning

confidence: 99%

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Adaptive evolution of sexual systems in pedunculate barnacles

et al. 2011

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How and why diverse sexual systems evolve are fascinating evolutionary questions, but few empirical studies have dealt with these questions in animals. Pedunculate (gooseneck) barnacles show such diversity, including simultaneous hermaphroditism, coexistence of dwarf males and hermaphrodites (androdioecy), and coexistence of dwarf males and females (dioecy). Here, we report the first phylogenetically controlled test of the hypothesis that the ultimate cause of the diverse sexual systems and presence of dwarf males in this group is limited mating opportunities for non-dwarf individuals, owing to mating in small groups. Within the pedunculate barnacle phylogeny, dwarf males and females have evolved repeatedly. Females are more likely to evolve in androdioecious than hermaphroditic populations, suggesting that evolution of dwarf males has preceded that of females in pedunculates. Both dwarf males and females are associated with a higher proportion of solitary individuals in the population, corroborating the hypothesis that limited mating opportunities have favoured evolution of these diverse sexual systems, which have puzzled biologists since Darwin.

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“…Moreover, few studies have searched for correlates of sexual reproduction and life history traits in haploid-diploid organisms (but see review of mosses in Crawford et al, 2009). Dioecy, or separate sexes, is often used as a proxy for the mating system in haploiddiploid organisms as the evolution of different sexes is likely driven by selection for outcrossing (Bell, 1997).…”

Section: Introductionmentioning

confidence: 99%

O father where art thou? Paternity analyses in a natural population of the haploid–diploid seaweed Chondrus crispus

et al. 2014

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The link between life history traits and mating systems in diploid organisms has been extensively addressed in the literature, whereas the degree of selfing and/or inbreeding in natural populations of haploid-diploid organisms, in which haploid gametophytes alternate with diploid sporophytes, has been rarely measured. Dioecy has often been used as a proxy for the mating system in these organisms. Yet, dioecy does not prevent the fusion of gametes from male and female gametophytes originating from the same sporophyte. This is likely a common occurrence when spores from the same parent are dispersed in clumps and recruit together. This pattern of clumped spore dispersal has been hypothesized to explain significant heterozygote deficiency in the dioecious haploid-diploid seaweed Chondrus crispus. Fronds and cystocarps (structures in which zygotes are mitotically amplified) were sampled in two 25 m 2 plots located within a high and a low intertidal zone and genotyped at 5 polymorphic microsatellite loci in order to explore the mating system directly using paternity analyses. Multiple males sired cystocarps on each female, but only one of the 423 paternal genotypes corresponded to a field-sampled gametophyte. Nevertheless, larger kinship coefficients were detected between males siring cystocarps on the same female in comparison with males in the entire population, confirming restricted spermatial and clumped spore dispersal. Such dispersal mechanisms may be a mode of reproductive assurance due to nonmotile gametes associated with putatively reduced effects of inbreeding depression because of the free-living haploid stage in C. crispus.

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Correlated Evolution of Sexual System and Life-History Traits in Mosses

Cited by 64 publications

References 92 publications

Increased diversification rates follow shifts to bisexuality in liverworts

Increased diversification rates follow shifts to bisexuality in liverworts

Adaptive evolution of sexual systems in pedunculate barnacles

O father where art thou? Paternity analyses in a natural population of the haploid–diploid seaweed Chondrus crispus

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