The Origin and Genetic Basis of Obligate Parthenogenesis in Daphnia pulex

Innes, David J.; Hebert, Paul D. N.

doi:10.2307/2408918

Cited by 146 publications

(198 citation statements)

References 29 publications

(57 reference statements)

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“…One of these groups consists of clones assigned to D. pulex s.s., while the other group represents F1 hybrids between this species and D. pulicaria. Both groups appear to have arisen polyphyletically, apparently as a result of the transmission of a gene producing sex-limited meiosis suppression (Innes & Hebert, 1988). There is a complex geographical pattern of breeding system variation in temperate Churchill ponds on average held 1.5 clones per pond compared with 1.2 clones from Scandinavia and are likely to be somewhat younger at no more than 3000-4000 years (L. J. Weider, personal communication) compared with around 10000 years for the latter (R. Vainola, personal communication).…”

Section: Discussionmentioning

confidence: 99%

Geographical cline in breeding systems and ploidy levels in European populations of Daphnia pulex

et al. 1994

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Ninety populations of Daphnia pulex from sites throughout the UK and Scandinavia were assayed for genetic variation at 11 variable enzyme loci. A latitudinally-related dine in both breeding system and ploidy level was observed. Southern populations (latitudes 52-59°N) comprised only diploid cyclic parthenogens. Northern populations (latitudes 68-71°N) were dominated by polyploid obligate parthenogens and diploid cyclic parthenogens were absent. An assemblage of populations from a site of intermediate latitude (6 1°N) included both diploid cyclic parthenogens and diploid obligate parthenogens. This dine parallels one previously described from temperate to arctic North America. The obligately parthenogenetic (asexual) clones were generally heterozygous at one or more loci for a common D. pulex allele plus an allele not found in cyclically parthenogenetic (sexual) populations of D. pulex: it is argued that these asexual clones arose polyphyletically following several independent hybridizations between D. pulex and an unrecognized but closely related taxon. Fifteen different asexual clones were detected and 25 of 28 asexual populations were uniclonal: the mean number of asexual clones per population was 1.21.

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Section: Discussionmentioning

confidence: 99%

Geographical cline in breeding systems and ploidy levels in European populations of Daphnia pulex

et al. 1994

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“…Cyclic parthenogenesis is the ancestral breeding system and the transition to obligate asexuality in D. pulex has been firmly linked to sex-limited meiosis suppression. Breeding studies have established that obligately asexual clones of this species are heterozygous for a sex-limited meiosis suppressor (Innes & Hebert, 1988). Females of such clones produce only diploid eggs, but their male progeny undergo meiosis to produce haploid sperm which transmit the meiosis suppressor and elicit the adoption of asexuality by half of the offspring, which arise from matings with cyclically parthenogenetic females.…”

Section: Introductionmentioning

confidence: 99%

Macrogeographic patterns of breeding system diversity in the Daphnia pulex group. I. Breeding systems of Canadian populations

et al. 1993

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Efforts to deduce the evolutionary significance of sexual reproduction from the taxonomic and ecological distributions of asexuals rely on the presumption that reversions of asexual taxa to sexual reproduction are rare. There is growing evidence, however, that reversions may be likely as long as asexuals are diploid, and some sexual populations persist. However, few systems have been studied in sufficient detail to provide insight into the nature of interactions between the sexual and asexual components of a single taxon. The cladoceran crustaceans Daphnia pulex and D. puilcaria both show variation in breeding system with some populations reproducing by cyclic and others by obligate parthenogenesis. The present study used allozymic analysis to characterize the breeding systems of both species across Canada. Although F1 hybrids were prevalent between the species and invariably reproduced by obligate parthenogenesis, each parent species showed regional variation in its breeding system. D. pulex reproduces by obligate parthenogenesis in eastern Canada but switches to cyclic parthenogenesis in the west with an abrupt transition coincident with the forest/prairie ecotone. D. pulicaria shows a divergent pattern, with populations on the priaries reproducing by obligate parthenogenesis, while those in eastern Canada and the far west are cyclic parthenogens. The results make clear that breeding systems in both taxa tend to be uniform over large areas. The discordance in breeding system employed by each species at specific sites suggests that the patterns of breeding system variation are not linked to environmental factors, but are instead a consequence of the interplay between historical factors, such as dispersion patterns from glacial ref ugia and the sites of origin of mutations promoting the transition to asexuality.

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“…Such males provide a vehicle for fertilizing the eggs of sexual females, thereby transmitting the genetic determinants of female-limited meiosis suppression (4, 5). Such sex-limited meiosis suppression provides a powerful mechanism for the recurrent transformation of sexual lineages into novel asexually produced genotypes by repeated crossings between male progeny of obligate asexuals and sexual females (5-8).Although several genetic types of obligate asexuality may exist within the Daphnia species complex (9), our current focus is on a system involving "contagious" obligate asexuality (5,7,8), which has resulted in a wide phylogenetic and geographic distribution of obligately parthenogenetic (OP) lineages in the eastern and midcontinental portions of North America.In cyclically parthenogenetic (CP) D. pulex, resting eggs are products of meiosis and fertilization, whereas, in OP females, they are produced by a pseudomeiotic process in which a germline cell undergoes an equational separation (10). Data from laboratory crosses initially suggested that a single dominant allele confers OP (7).…”

mentioning

confidence: 99%

“…Although several genetic types of obligate asexuality may exist within the Daphnia species complex (9), our current focus is on a system involving "contagious" obligate asexuality (5,7,8), which has resulted in a wide phylogenetic and geographic distribution of obligately parthenogenetic (OP) lineages in the eastern and midcontinental portions of North America.…”

mentioning

confidence: 99%

“…Such sex-limited meiosis suppression provides a powerful mechanism for the recurrent transformation of sexual lineages into novel asexually produced genotypes by repeated crossings between male progeny of obligate asexuals and sexual females (5)(6)(7)(8). Although several genetic types of obligate asexuality may exist within the Daphnia species complex (9), our current focus is on a system involving "contagious" obligate asexuality (5,7,8), which has resulted in a wide phylogenetic and geographic distribution of obligately parthenogenetic (OP) lineages in the eastern and midcontinental portions of North America.…”

mentioning

confidence: 99%

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The spread of a transposon insertion in Rec8 is associated with obligate asexuality in Daphnia

Eads

Tsuchiya²,

Andrews

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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Although transitions from sexual to asexual reproduction are thought to have important evolutionary consequences, little is known about the mechanistic underpinnings of these changes. The cyclical parthenogen Daphnia pulex is a powerful model in which to address these issues because female-limited meiosis suppression can be transmitted to sexual individuals via males, providing the opportunity for genetic dissection of the trait. A previous study identified genomic regions differentiating obligately asexual females from their sexual counterparts, and a candidate gene within one such region, encoding the meiotic cohesin Rec8, is the subject of this investigation. The D. pulex genome contains three Rec8 loci, all of which are quite polymorphic. However, at one of the loci, all obligately asexual clones carry an allele containing an identical upstream insertion of a transposable element as well as a frameshift mutation, both of which are completely absent from sexual lineages. The low level of variation within the insertion allele across all asexual lineages suggests that this element may be in the process of spreading through the species, and abrogation or modification of Rec8 function is possibly responsible for converting meiotically reproducing lineages into obligate asexuals.T ransitions between sexual and asexual reproduction are believed to have important evolutionary and ecological consequences (1, 2). However, the molecular, genetic, and cytological underpinnings of such transitions remain largely uncharacterized. Most asexual metazoan taxa are obligate parthenogens (3), making formal genetic analysis of these transitions impossible. In contrast, for the cyclical parthenogen Daphnia pulex, there are numerous lineages in which the females are obligately asexual, but still retain the ability to produce males capable of haploid sperm production via meiosis. Such males provide a vehicle for fertilizing the eggs of sexual females, thereby transmitting the genetic determinants of female-limited meiosis suppression (4, 5). Such sex-limited meiosis suppression provides a powerful mechanism for the recurrent transformation of sexual lineages into novel asexually produced genotypes by repeated crossings between male progeny of obligate asexuals and sexual females (5-8).Although several genetic types of obligate asexuality may exist within the Daphnia species complex (9), our current focus is on a system involving "contagious" obligate asexuality (5,7,8), which has resulted in a wide phylogenetic and geographic distribution of obligately parthenogenetic (OP) lineages in the eastern and midcontinental portions of North America.In cyclically parthenogenetic (CP) D. pulex, resting eggs are products of meiosis and fertilization, whereas, in OP females, they are produced by a pseudomeiotic process in which a germline cell undergoes an equational separation (10). Data from laboratory crosses initially suggested that a single dominant allele confers OP (7). However, a recent marker association study of a collection of OP an...

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The Origin and Genetic Basis of Obligate Parthenogenesis in Daphnia pulex

Cited by 146 publications

References 29 publications

Geographical cline in breeding systems and ploidy levels in European populations of Daphnia pulex

Geographical cline in breeding systems and ploidy levels in European populations of Daphnia pulex

Macrogeographic patterns of breeding system diversity in the Daphnia pulex group. I. Breeding systems of Canadian populations

The spread of a transposon insertion in Rec8 is associated with obligate asexuality in Daphnia

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