Triparental inheritance inDictyostelium

Sex promotes the recombination and reassortment of genetic material and is prevalent across eukaryotes, although our knowledge of the molecular details of sexual inheritance is scant in several major lineages. In social amoebae, sex involves a promiscuous mixing of cytoplasm before zygotes consume the majority of cells, but for technical reasons, sexual progeny have been difficult to obtain and study. We report here genome-wide characterization of meiotic progeny inDictyostelium discoideum. We find that recombination occurs at high frequency in pairwise crosses between all three mating types, despite the absence of the Spo11 enzyme that is normally required to initiate crossover formation. Fusions of more than two gametes to form transient syncytia lead to frequent triparental inheritance, with haploid meiotic progeny bearing recombined nuclear haplotypes from two parents and the mitochondrial genome from a third. Cells that do not contribute genetically to theDictyosteliumzygote nucleus thereby have a stake in the next haploid generation.D. discoideummitochondrial genomes are polymorphic, and our findings raise the possibility that some of this variation might be a result of sexual selection on genes that can promote the spread of individual organelle genomes during sex. This kind of self-interested mitochondrial behavior may have had important consequences during eukaryogenesis and the initial evolution of sex.

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Triparental inheritance in Dictyostelium

10.1101/385708 ◽

2018 ◽

Author(s):

Gareth Bloomfield ◽

Peggy Paschke ◽

Marina Okamoto ◽

Tim J. Stevens ◽

Hideko Urushihara

Keyword(s):

Mitochondrial Genome ◽

Dictyostelium Discoideum ◽

High Frequency ◽

Genetic Material ◽

Lateral Transfer ◽

Mating Types ◽

Zygote Nucleus ◽

Social Amoebae

AbstractSex promotes the recombination and reassortment of genetic material and is prevalent across eukaryotes. In social amoebae sex involves a promiscuous mixing of cytoplasm before zygotes consume the majority of cells. We report here the first genomewide characterisation of meiotic progeny in Dictyostelium discoideum. We find that recombination occurs at high frequency in pairwise crosses between all three mating types, despite the absence of the SPO11 enzyme that is normally required to initiate crossover formation. In crosses involving three strains, transient fusions involving more than two gametes frequently lead to triparental inheritance, with recombined nuclear haplotypes inherited from two parents and the mitochondrial genome from a third. Cells that do not contribute genetically to the Dictyostelium zygote nucleus thereby have a stake in the next haploid generation. We suggest that this lateral transfer helps to enforce cooperation in this confictual system.

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Characterization Of Interspecific Gene Flows at The Genome-wide Level in a Natural Ecosystem The Massane Forest Reveals New Insights Into Horizontal Transfer In plants.

10.1101/2021.12.19.471934 ◽

2021 ◽

Author(s):

Emilie Aubin ◽

Christel Llauro ◽

Joseph Garrigue ◽

Marie Mirouze ◽

Olivier Panaud ◽

...

Keyword(s):

Wild Species ◽

Horizontal Transfer ◽

Genetic Material ◽

Natural Ecosystem ◽

Natural Ecosystems ◽

Model Species ◽

Ecological Relationships ◽

Genome Wide ◽

Genome Level

Horizontal transfer (HT) refers to the exchange of genetic material between divergent species by mechanisms other than reproduction. In recent years, several studies have demonstrated HTs in plants, particularly in the context of parasitic relationships and in model species. However, very little is known about HT in natural ecosystems, especially those involving non-parasitic wild species, and the nature of the ecological relationships that promote these HTs. In this work, we conducted a pilot study investigating HTs by sequencing the genomes of 17 wild non-model species from a natural ecosystem, the Massane forest, located in southern France. To this end, we developed a new computational pipeline called INTERCHANGE that is able to characterize HTs at the whole genome level without prior annotation and directly in the raw sequencing reads. Using this pipeline, we identified 12 HT events, half of which occurred between lianas and trees. We found that only LTRs-retrotransposons and predominantly those from the Copia superfamily were transferred between these wild species. This study revealed a possible new route for HTs between non-parasitic plants and provides new insights into the genomic characteristics of horizontally transferred DNA in plant genomes.

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