Triparental inheritance in Dictyostelium
Triparental inheritance in Dictyostelium
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DOI：
10.1073/pnas.1814425116
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发表时间：
2019-02-05
影响因子：
11.1
通讯作者：
Urushihara, Hideko
中科院分区：
文献类型：
--
作者：
Bloomfield, Gareth;Paschke, Peggy;Urushihara, Hideko
有性促进遗传物质的重组和重配，并且在真核生物中普遍存在，尽管我们对几个主要谱系的有性遗传的分子细节知之甚少。在社会性变形虫中，性涉及在受精卵消耗大部分细胞之前细胞质的混杂混合，但由于技术原因，有性后代很难获得和研究。我们在此报告了盘基网柄菌减数分裂后代的全基因组特征。我们发现，尽管缺乏启动交叉形成通常所需的 Spo11 酶，但在所有三种交配类型之间的成对杂交中，重组发生频率很高。两个以上配子融合形成短暂合胞体导致频繁的三亲遗传，单倍体减数分裂后代携带来自两个亲本的重组核单倍型和来自第三个亲本的线粒体基因组。因此，对盘基网柄菌合子核没有遗传贡献的细胞在下一代单倍体中具有利害关系。盘状 D. discoideum 线粒体基因组是多态性的，我们的研究结果提出了一种可能性，即其中一些变异可能是基因性选择的结果，这些基因可以促进性过程中个体细胞器基因组的传播。这种自私的线粒体行为可能在真核发生和性的最初进化过程中产生了重要的后果。
Sex promotes the recombination and reassortment of genetic material and is prevalent across eukaryotes, although our knowledge of themolecular 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 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. 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 the Dictyostelium zygote nucleus thereby have a stake in the next haploid generation. D. discoideum mitochondrial 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.