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Diversity in the reproductive modes of European Daphnia pulicaria deviates from the geographical parthenogenesis.

Dufresne F, Marková S, Vergilino R, Ventura M, Kotlík P - PLoS ONE (2011)

Bottom Line: These newly formed asexual lineages are differentially distributed being found predominantly at high latitudes.Inferred transitions to obligate parthenogenesis have occurred only in HTM, most likely as a result of hybridizations.In contrast to North American populations, these transitions do not appear to involve meiosis suppressor genes and have not been accompanied by polyploidy.

View Article: PubMed Central - PubMed

Affiliation: Département de Biologie, Centre d'Études Nordiques, Université du Québec à Rimouski, Rimouski, Québec, Canada. france_dufresne@uqar.qc.ca

ABSTRACT

Background: Multiple transitions to obligate parthenogenesis have occurred in the Daphnia pulex complex in North America. These newly formed asexual lineages are differentially distributed being found predominantly at high latitudes. This conforms to the rule of geographical parthenogenesis postulating prevalence of asexuals at high latitudes and altitudes. While the reproductive mode of high-latitude populations is relatively well studied, little is known about the reproduction mode in high altitudes. This study aimed to assess the reproductive mode of Daphnia pulicaria, a species of the D. pulex complex, from high altitude lakes in Europe.

Methodology/principal findings: Variation at eight microsatellite loci revealed that D. pulicaria from the High Tatra Mountains (HTM) had low genotype richness and showed excess of heterozygotes and significant deviations from Hardy-Weinberg expectations, and was thus congruent with reproduction by obligate parthenogenesis. By contrast, populations from the Pyrenees (Pyr) were generally in Hardy-Weinberg equilibrium and had higher genotypic richness, suggesting that they are cyclic parthenogens. Four lakes from lowland areas (LLaP) had populations with an uncertain or mixed breeding mode. All D. pulicaria had mtDNA ND5 haplotypes of the European D. pulicaria lineage. Pyr were distinct from LLaP and HTM at the ND5 gene. By contrast, HTM shared two haplotypes with LLaP and one with Pyr. Principal Coordinate Analysis of the microsatellite data revealed clear genetic differentiation into three groups. HTM isolates were intermediate to Pyr and LLaP, congruent with a hybrid origin.

Conclusion/significance: Inferred transitions to obligate parthenogenesis have occurred only in HTM, most likely as a result of hybridizations. In contrast to North American populations, these transitions do not appear to involve meiosis suppressor genes and have not been accompanied by polyploidy. The absence of obligate parthenogenesis in Pyr, an environment highly similar to the HTM, may be due to the lack of opportunities for hybridization.

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Geographic location of sampling sites.For the lowland populations (LLaP) each of the four sites is shown with a separate symbol while for the alpine populations single symbol is shown for each region (HTM and Pyr) where the sites were situated close to each other.
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pone-0020049-g001: Geographic location of sampling sites.For the lowland populations (LLaP) each of the four sites is shown with a separate symbol while for the alpine populations single symbol is shown for each region (HTM and Pyr) where the sites were situated close to each other.

Mentions: From 606 analyzed individuals collected in 18 water bodies representing the alpine and lowland populations of Europe (Figure 1) we obtained 561 isolates with complete genotype, which were used in subsequent statistical analyses (Table S1). A total of 64 alleles were identified at the eight microsatellite loci. Loci Dp519, Dp 514, and Dp502 had the lowest number of alleles (five) whereas locus Dp514alt was the most variable one, with 22 alleles. All analyzed individuals from two alpine lakes in the High Tatra Mountains (HTM; MHinc and ZelJ) were homozygous for the same allele at each locus, while isolates from all the other lakes and ponds were polymorphic.


Diversity in the reproductive modes of European Daphnia pulicaria deviates from the geographical parthenogenesis.

Dufresne F, Marková S, Vergilino R, Ventura M, Kotlík P - PLoS ONE (2011)

Geographic location of sampling sites.For the lowland populations (LLaP) each of the four sites is shown with a separate symbol while for the alpine populations single symbol is shown for each region (HTM and Pyr) where the sites were situated close to each other.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3104988&req=5

pone-0020049-g001: Geographic location of sampling sites.For the lowland populations (LLaP) each of the four sites is shown with a separate symbol while for the alpine populations single symbol is shown for each region (HTM and Pyr) where the sites were situated close to each other.
Mentions: From 606 analyzed individuals collected in 18 water bodies representing the alpine and lowland populations of Europe (Figure 1) we obtained 561 isolates with complete genotype, which were used in subsequent statistical analyses (Table S1). A total of 64 alleles were identified at the eight microsatellite loci. Loci Dp519, Dp 514, and Dp502 had the lowest number of alleles (five) whereas locus Dp514alt was the most variable one, with 22 alleles. All analyzed individuals from two alpine lakes in the High Tatra Mountains (HTM; MHinc and ZelJ) were homozygous for the same allele at each locus, while isolates from all the other lakes and ponds were polymorphic.

Bottom Line: These newly formed asexual lineages are differentially distributed being found predominantly at high latitudes.Inferred transitions to obligate parthenogenesis have occurred only in HTM, most likely as a result of hybridizations.In contrast to North American populations, these transitions do not appear to involve meiosis suppressor genes and have not been accompanied by polyploidy.

View Article: PubMed Central - PubMed

Affiliation: Département de Biologie, Centre d'Études Nordiques, Université du Québec à Rimouski, Rimouski, Québec, Canada. france_dufresne@uqar.qc.ca

ABSTRACT

Background: Multiple transitions to obligate parthenogenesis have occurred in the Daphnia pulex complex in North America. These newly formed asexual lineages are differentially distributed being found predominantly at high latitudes. This conforms to the rule of geographical parthenogenesis postulating prevalence of asexuals at high latitudes and altitudes. While the reproductive mode of high-latitude populations is relatively well studied, little is known about the reproduction mode in high altitudes. This study aimed to assess the reproductive mode of Daphnia pulicaria, a species of the D. pulex complex, from high altitude lakes in Europe.

Methodology/principal findings: Variation at eight microsatellite loci revealed that D. pulicaria from the High Tatra Mountains (HTM) had low genotype richness and showed excess of heterozygotes and significant deviations from Hardy-Weinberg expectations, and was thus congruent with reproduction by obligate parthenogenesis. By contrast, populations from the Pyrenees (Pyr) were generally in Hardy-Weinberg equilibrium and had higher genotypic richness, suggesting that they are cyclic parthenogens. Four lakes from lowland areas (LLaP) had populations with an uncertain or mixed breeding mode. All D. pulicaria had mtDNA ND5 haplotypes of the European D. pulicaria lineage. Pyr were distinct from LLaP and HTM at the ND5 gene. By contrast, HTM shared two haplotypes with LLaP and one with Pyr. Principal Coordinate Analysis of the microsatellite data revealed clear genetic differentiation into three groups. HTM isolates were intermediate to Pyr and LLaP, congruent with a hybrid origin.

Conclusion/significance: Inferred transitions to obligate parthenogenesis have occurred only in HTM, most likely as a result of hybridizations. In contrast to North American populations, these transitions do not appear to involve meiosis suppressor genes and have not been accompanied by polyploidy. The absence of obligate parthenogenesis in Pyr, an environment highly similar to the HTM, may be due to the lack of opportunities for hybridization.

Show MeSH
Related in: MedlinePlus