Genotypic diversity and variation in mode of reproduction among populations in the Daphnia pulex group

Innes, David J.; Schwartz, Steven S.; Hebert, Paul D. N.

doi:10.1038/hdy.1986.134

Cited by 72 publications

(75 citation statements)

References 22 publications

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“…Genotypic frequencies in 18 of 20 natural populations were out of HWE and linkage disequilibrium between genotypes at MPI and PGM was frequent. Similar genotypic characteristics have been reported in studies of other asexual taxa (Hoffmann, 1986;Innes et al, 1986). The laboratory rearing studies indicated that single C. vidua females could initiate cultures and that their offspring were genetically identical.…”

Section: Discussionsupporting

confidence: 63%

Apomictic parthenogenesis and genotypic diversity in Cypridopsis vidua (Ostracoda: Cyprididae)

Havel

1989

Heredity

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Based on sex ratios, the crustacean subclass Ostracoda appears to have made frequent transitions from sexual to asexual reproduction. However few genetic data are available verifying their mode of reproduction. The current report provides such evidence for apomictic pathenogenesis in the cosmopolitan cypridid ostracode Cypridopsis vidua. Sex ratio analysis indicated that natural populations are exclusively female. Allozyme phenotypes in 18 of 20 natural populations showed strong departures from Hardy-Weinberg expectations at single loci, and three of four populations had non-random associations of phenotypes at MPI and PGM. Allozyme phenotypes at these loci suggested that polyploids were present in half these populations and were more common in the low arctic site than in the temperate sites. Most natural populations of C. vidua displayed high levels of genotypic diversity, with a total of 77 unique clones detected and up to 24 clones per pond. Breeding studies on 64 isofemale lines established that parthenogenesis is apomictic and that mutation rates are less than i0.

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Section: Discussionsupporting

confidence: 63%

Apomictic parthenogenesis and genotypic diversity in Cypridopsis vidua (Ostracoda: Cyprididae)

Havel

1989

Heredity

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“…In fact, asexual populations of R. padi consisted of only one dominant allozyme clone that was widely distributed in France and which has apparently achieved tremendous ecological success, at least in the short-term. A comparable reduction in genotypic diversity has been demonstrated in obligately asexual populations of cladocerans when compared with their cyclically parthenogenetic relatives (Innes et a!., 1986;Hebert et al, 1988).…”

Section: Discussionmentioning

confidence: 78%

“…hoek, 1979(Vrijen-. hoek, , 1993, frogs (Hotz et a!., 1985), snails (Lively, 1992), moths (Harshman & Futuyama, 1985) and cladocerans (Innes et a!., 1986;Hebert et a!., 1988). However, surprisingly little attention has been directed towards aphids which are excellent candidates for such studies.…”

Section: Introductionmentioning

confidence: 99%

Genetic diversity and mode of reproduction in French populations of the aphid Rhopalosiphum padi L.

Simon¹,

Carrel²,

Hebert

et al. 1996

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Flolocyclic individuals of the aphid Rhopalosiphum padi reproduce by cyclical parthenogenesis, while anholocyclic individuals are obligate parthenogens. Although admixed on the secondary hosts in summer, holocyclic and anholocyclic populations occur separately on the primary and secondary hosts during winter and spring. In this study, we compared the genetic diversity and population structure of holocyclic and anholocyclic populations collected in spring in the northern half of France. We also analysed the genetic composition of summer populations of R. padi on its secondary hosts. In spring, holocyclic populations were in Hardy-Weinberg equilibrium at individual loci and had a relatively high genotypic diversity. Conversely, anholocyclic populations deviated from Hardy-Weinberg equilibrium and often consisted of a single clone. Moreover, these populations showed very low mean heterozygosities compared with holocyclic populations. Analysis of summer populations suggested that in regions with cold winters, summer populations were largely recruited from holocyclic clones, whereas in areas with mild winters, summer populations were mainly derived from anholocyclic clones. These results permit an assessment of the geographical distribution of the two modes of reproduction on a large scale. The reasons for the diminished heterozygosity of anholocyclic populations are also discussed in relation to the mechanisms which may induce transitions to asexuality in aphids.

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“…Recent work established the presence of F1 hybrids between these species and has shown that such hybrids always reproduce by obligate parthenogenesis (Hebert et a!., 1989a;Crease & Lynch, 1991). Earlier studies incorrectly classified these hybrids as asexual clones of D. pulex (Hebert & Crease, 1983;Lynch 1983;Innes et al, 1986). It remains clear, however, that D. pulex s.s. shows variable reproductive behaviour, with some populations reproducing by cyclic and others by obligate parthenogenesis.…”

Section: Introductionmentioning

confidence: 87%

“…Clonal diversity is exceptionally high (Hebert et a!., 1988, 1 989a) and joint allozyme/mtDNA analysis has confirmed the polyphyletic origins of asexuality (Crease et a!., 1989). Prior surveys of breeding systems, however, have revealed two anomalies -the sustained presence of sexual populations in regions dominated by asexuals (Hebert et al,1 989a) and an apparent regional variation in the dominant breeding system (Innes et al, 1986). …”

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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Genotypic diversity and variation in mode of reproduction among populations in the Daphnia pulex group

Cited by 72 publications

References 22 publications

Apomictic parthenogenesis and genotypic diversity in Cypridopsis vidua (Ostracoda: Cyprididae)

Apomictic parthenogenesis and genotypic diversity in Cypridopsis vidua (Ostracoda: Cyprididae)

Genetic diversity and mode of reproduction in French populations of the aphid Rhopalosiphum padi L.

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

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