Evolution of haploid selection in predominantly diploid organisms
Evolution of haploid selection in predominantly diploid organisms
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DOI：
10.1073/pnas.1512004112
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发表时间：
2015-12-29
影响因子：
11.1
通讯作者：
Immler, Simone
中科院分区：
文献类型：
--
作者：
Otto, Sarah P.;Scott, Michael F.;Immler, Simone
二倍体生物体操纵其单倍体配子经历选择的程度。动物产生的精子通常含有大多数蛋白质和RNA的二倍体补充，限制了单倍体基因的选择。然而，植物在花粉中表现出广泛的表达，具有活跃的转录单倍体基因组。在这里，我们分析了跟踪基因进化的模型，这些基因改变了单倍体选择的强度，以预测进化何时加剧，何时削弱雄配子竞争受精的“选择性竞技场”。考虑到有害的突变，进化导致二倍体母亲在单倍体精子/花粉中加强选择，因为这减少了二倍体后代遗传的突变负荷。然而，如果选择在单倍体和二倍体中起相反的作用(“倍性拮抗选择”)，母亲会进化到减少单倍体选择，以避免选择性地放大对其后代有害的等位基因。因此，在母体控制下，单倍体阶段的选择要么最大化，要么达到中间状态，这取决于相对于倍性拮抗选择程度的有害突变率。相比之下，进化通常会导致二倍体父亲最大限度地掩盖配子中的突变，每当掩盖(例如，通过转录共享)增加父亲配子的平均适合度时。我们讨论了关于单倍体选择范围的母父冲突的含义，并描述了需要进行的实证研究，以完善我们对看似二倍体生物体中单倍体选择的理解。
Diploid organisms manipulate the extent to which their haploid gametes experience selection. Animals typically produce sperm with a diploid complement of most proteins and RNA, limiting selection on the haploid genotype. Plants, however, exhibit extensive expression in pollen, with actively transcribed haploid genomes. Here we analyze models that track the evolution of genes that modify the strength of haploid selection to predict when evolution intensifies and when it dampens the "selective arena" within which male gametes compete for fertilization. Considering deleterious mutations, evolution leads diploid mothers to strengthen selection among haploid sperm/pollen, because this reduces the mutation load inherited by their diploid offspring. If, however, selection acts in opposite directions in haploids and diploids ("ploidally antagonistic selection"), mothers evolve to reduce haploid selection to avoid selectively amplifying alleles harmful to their offspring. Consequently, with maternal control, selection in the haploid phase either is maximized or reaches an intermediate state, depending on the deleterious mutation rate relative to the extent of ploidally antagonistic selection. By contrast, evolution generally leads diploid fathers to mask mutations in their gametes to the maximum extent possible, whenever masking (e.g., through transcript sharing) increases the average fitness of a father's gametes. We discuss the implications of this maternal-paternal conflict over the extent of haploid selection and describe empirical studies needed to refine our understanding of haploid selection among seemingly diploid organisms.