Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211, USA.
Department of Electrical Engineering and Computer Science, University of Missouri, Columbia, Missouri 65211, USA.
Plant Cell. 2021 May 31;33(4):901-916. doi: 10.1093/plcell/koab029.
The phenotypic consequences of the addition or subtraction of part of a chromosome is more severe than changing the dosage of the whole genome. By crossing diploid trisomies to a haploid inducer, we identified 17 distal segmental haploid disomies that cover ∼80% of the maize genome. Disomic haploids provide a level of genomic imbalance that is not ordinarily achievable in multicellular eukaryotes, allowing the impact to be stronger and more easily studied. Transcriptome size estimates revealed that a few disomies inversely modulate most of the transcriptome. Based on RNA sequencing, the expression levels of genes located on the varied chromosome arms (cis) in disomies ranged from being proportional to chromosomal dosage (dosage effect) to showing dosage compensation with no expression change with dosage. For genes not located on the varied chromosome arm (trans), an obvious trans-acting effect can be observed, with the majority showing a decreased modulation (inverse effect). The extent of dosage compensation of varied cis genes correlates with the extent of trans inverse effects across the 17 genomic regions studied. The results also have implications for the role of stoichiometry in gene expression, the control of quantitative traits, and the evolution of dosage-sensitive genes.
添加或减少染色体的一部分的表型后果比改变整个基因组的剂量更为严重。通过将二倍体三体与单倍体诱导剂杂交，我们鉴定了 17 个覆盖约 80%玉米基因组的远端节段单体二倍体。单体二倍体提供了通常在多细胞真核生物中无法实现的基因组失衡水平，从而使影响更强且更容易研究。转录组大小估计表明，少数二倍体反调节大多数转录组。基于 RNA 测序，位于不同染色体臂上的基因（顺式）在二倍体中的表达水平从与染色体剂量成比例（剂量效应）到与剂量无关的表达变化（剂量补偿）不等。对于不在变化的染色体臂上的基因（反式），可以观察到明显的反式作用，大多数基因的调节降低（反式效应）。所研究的 17 个基因组区域中，变化的顺式基因的剂量补偿程度与跨区域的反式反向效应的程度相关。结果还对基因表达中化学计量的作用、数量性状的控制以及剂量敏感基因的进化具有启示意义。
