Self-fertilization in mosses: a comparison of heterozygote deficiency between species with combined versus separate sexes

Eppley, Sarah M.; Taylor, Philip; Jesson, Linley K.

doi:10.1038/sj.hdy.6800900

Cited by 64 publications

(56 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Heterozygote deficiency (F IS ) has previously been estimated to be ∼ 0.41 ± 0.11 for dioicous bryophytes (based on five different species, Eppley et al, 2007). We detected higher values in three of the studied populations (0.64, 0.59 and 0.48, respectively), and lower in one population (0.10) ( Table 1).…”

Section: Inbreedingmentioning

confidence: 71%

Balance between inbreeding and outcrossing in a nannandrous species, the moss Homalothecium lutescens

2015

View full text Add to dashboard Cite

Epiphytic dwarf males on the females present a possible solution to the problem of short fertilization distances in mosses. However, leptokurtic spore dispersal makes dwarf males likely to be closely related to their host shoot, with an accompanying risk of inbreeding. The capacity of a female to harbour a high number of different dwarf males suggests that there may be mechanisms in place that counteract inbreeding, such as polyandry and post-fertilization selection. We have genotyped sporophytes, female host shoots and dwarf males in four populations of the moss Homalothecium lutescens. We found no evidence of selective sporophyte abortion based on level of heterozygosity. The occurrence of entirely homozygous sporophytes together with significantly positive inbreeding coefficients in three of the populations (mean F IS between 0.48 and 0.64) suggest frequent mother-son mating events. However, 23% of all sampled sporophytes had a higher level of heterozygosity compared with the mean expected heterozygosity at the population level. Polyandry was frequent, on average 59% of the sporophytes on a female shoot were sired by distinct fathers. In conclusion, sporadic fertilizations by dwarf males originating from nonhost female shoots appear to counteract strong inbreeding.

show abstract

Section: Inbreedingmentioning

confidence: 71%

Balance between inbreeding and outcrossing in a nannandrous species, the moss Homalothecium lutescens

2015

View full text Add to dashboard Cite

show abstract

“…Quantifying inbreeding in hermaphrodites P Jarne and P David tetraploids (Ronfort et al, 1998) and situations in which both gametophytic and sporophytic selfing may occur, such as in mosses (see Eppley et al, 2007). A strong advantage of this approach is that F is almost systematically estimated in analyses of population genetic structure, based on co-dominant markers, providing an ample source of data.…”

Section: Population Structure Approachmentioning

confidence: 99%

“…It is common in angiosperms, a group with o10% dioecious species (Renner and Ricklefs, 1995), as well as in other plants, such as mosses (Eppley et al, 2007), and in hermaphroditic animals, such as mollusks or trematodes (Jarne and Auld, 2006). It also occurs in fungi.…”

Section: Introductionmentioning

confidence: 99%

Quantifying inbreeding in natural populations of hermaphroditic organisms

Jarne

David

2008

Heredity

View full text Add to dashboard Cite

We review molecular methods for estimating selfing rates and inbreeding in populations. Two main approaches are available: the population structure approach (PSA) and progeny-array approach (PAA). The PSA approach relies on single-generation samples and produces estimates that integrate the inbreeding history over several generations, but is based on strong assumptions (for example, inbreeding equilibrium). The PSA has classically relied on single-locus inbreeding coefficients averaged over loci. Unfortunately PSA estimates are very sensitive to technical problems such as the occurrence of null alleles at one or more of the loci. Consequently inbreeding might be substantially overestimated, especially in outbred populations. However, the robustness of the PSA has recently been greatly improved by the development of multilocus methods free of such bias. The PAA, on the other hand, is based on the comparison between offspring and mother genotypes. As a consequence, PAA estimates do not reflect long-term inbreeding history but only recent mating events of the maternal individuals studied ('here and now' selfing). In addition to selfing rates, the PAA allows estimating other mating system parameters, including biparental inbreeding and the correlation of selfing among sibs. Although PAA estimates could also be biased by technical problems, incompatibilities between the mother's genotype and her offspring allow the identification and correction of such bias. For all methods, we provide guidelines on the required number of loci and sample sizes. We conclude that the PSA and PAA are equally robust, provided multilocus information is used. Although experimental constraints may make the PAA more demanding, especially in animals, the two methods provide complementary information, and can fruitfully be conducted together.

show abstract

“…All sporophytes had karyotypes consistent with mating within a clonal clump [79,81]. Allozyme and microsatellite studies in monoecious mosses find that most sporophytes are homozygous, consistent with frequent gametophytic selfing [82][83][84], although one study of monoecious liverworts found that 5% of sporophytes of Pellia borealis and 25% of sporophytes of Pellia epiphylla were sired by mating between gametophytes [85,86].…”

Section: (D) Monoecious Matingmentioning

confidence: 99%

Living together and living apart: the sexual lives of bryophytes

Haig¹

2016

Phil. Trans. R. Soc. B

View full text Add to dashboard Cite

One contribution of 15 to a theme issue 'Weird sex: the underappreciated diversity of sexual reproduction'. Haploid gametophytes of bryophytes spread by clonal growth but mate locally, within an area defined by the range of sperm movement. Rarity of establishment from spores or vegetative competition can result in unisexual populations unable to reproduce sexually. Females typically outcompete males, probably because females expend fewer resources than males on the production of gametes. Extreme sexual dimorphism-tiny males growing as epiphytes on much larger females-has evolved many times. Haploid selfing is common in bryophytes with bisexual gametophytes, and results in completely homozygous sporophytes. Spores from these sporophytes recapitulate the genotype of their single haploid parent. This process can be considered analogous to 'asexual' reproduction with 'sexual' reproduction occurring after rare outcrossing between haploid parents. Ferns also produce bisexual haploid gametophytes but, unlike bryophytes, haploid outcrossing predominates over haploid selfing. This difference is probably related to clonal growth and vegetative competition occurring in the haploid but not the diploid phase in bryophytes, but the reverse in ferns. Ferns are thereby subject to stronger inbreeding depression than bryophytes.This article is part of the themed issue 'Weird sex: the underappreciated diversity of sexual reproduction'. Sexual lives of bryophytesAnimal life histories are characterized by multicellular diploid individuals that produce haploid gametes by meiosis. Gametes are the only haploid cells of such life cycles. The life histories of bryophytes (mosses, liverworts and hornworts) are fundamentally different. Multicellular haploid gametophytes (gameteproducing plants) produce gametes by mitosis. The fertilization of an ovum by a sperm produces a zygote that develops into a short-lived multicellular diploid sporophyte (spore-producing plant) that grows attached to the maternal gametophyte on which it depends for nutrients. Sporophytes produce haploid spores by meiosis that germinate to produce new gametophytes (figure 1). Mating is restricted to the distance over which sperm can find ova, usually in the millimetre to centimetre range [1]. Clonal expansion occurs via vegetative spread of gametophytes into neighbouring space and production of gemmae (asexual propagules) that disperse gametophytic clones to new sites [2].Gametophytes of dioecious bryophytes are unisexual, producing either eggs or sperm, but not both. Males and females compete for space but require close proximity for sexual reproduction. By contrast, gametophytes of monoecious bryophytes are bisexual, able to produce both eggs and sperm. A bisexual gametophyte that fertilizes its own eggs engenders homozygous sporophytes all of whose spores are genetically identical (excepting meiotic errors and postzygotic mutations). Roughly 70% of liverworts, 60% of mosses and 40% of hornworts are dioecious [3]. Bryophyte life cycles are not only fascinating in th...

show abstract

Self-fertilization in mosses: a comparison of heterozygote deficiency between species with combined versus separate sexes

Cited by 64 publications

References 39 publications

Balance between inbreeding and outcrossing in a nannandrous species, the moss Homalothecium lutescens

Balance between inbreeding and outcrossing in a nannandrous species, the moss Homalothecium lutescens

Quantifying inbreeding in natural populations of hermaphroditic organisms

Living together and living apart: the sexual lives of bryophytes

Contact Info

Product

Resources

About