Division of Biological Sciences, University of Missouri, 117 Tucker Hall, Columbia, MO 65211, USA.
Theor Appl Genet. 2010 Jan;120(2):341-53. doi: 10.1007/s00122-009-1113-3.
Heterosis and polyploidy are two important aspects of plant evolution. To examine these issues, we conducted a global gene expression study of a maize ploidy series as well as a set of tetraploid inbred and hybrid lines. This gene expression analysis complements an earlier phenotypic study of these same materials. We find that ploidy change affects a large fraction of the genome, albeit at low levels; gene expression changes rarely exceed 2-fold and are typically not statistically significant. The most common gene expression profile we detected is greater than linear increase from monoploid to diploid, and reductions from diploid to triploid and from triploid to tetraploid, a trend that mirrors plant stature. When examining heterosis in tetraploid maize lines, we found a large fraction of the genome impacted but the majority of changes were not statistically significant at 2-fold or less. Non-additive expression was common in the hybrids, and the extent of non-additivity increased both in number and magnitude from duplex to quadruplex hybrids. Overall, we find that gene expression trends mirror observations from the phenotypic studies; however, obvious mechanistic connections remain unknown.
杂种优势和多倍体是植物进化的两个重要方面。为了研究这些问题，我们对玉米倍性系列以及一组四倍体自交系和杂交系进行了全球基因表达研究。这项基因表达分析补充了对这些相同材料的早期表型研究。我们发现，倍性变化影响了基因组的很大一部分，尽管程度较低；基因表达变化很少超过 2 倍，通常不具有统计学意义。我们检测到的最常见的基因表达模式是从单倍体到二倍体的线性增加，以及从二倍体到三倍体和从三倍体到四倍体的减少，这一趋势反映了植物的形态。当我们研究四倍体玉米品系的杂种优势时，发现基因组的很大一部分受到了影响，但大多数变化在 2 倍或以下时没有统计学意义。非加性表达在杂种中很常见，并且从双杂交到四杂交杂种，非加性表达的数量和幅度都增加了。总的来说，我们发现基因表达趋势反映了表型研究的观察结果；然而，明显的机制联系仍然未知。
