Nonadditive gene expression in diploid and triploid hybrids of maize
Nonadditive gene expression in diploid and triploid hybrids of maize
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DOI：
10.1534/genetics.104.032987
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发表时间：
2005-01-01
期刊：
影响因子：
3.3
通讯作者：
Birchler, JA
中科院分区：
文献类型：
--
作者：
Auger, DL;Gray, AD;Birchler, JA
杂种优势的分子基础仍然是未知的，尽管这一现象在进化和实际育种计划中的重要性。为了阐明杂种优势的分子基础，需要了解基因在近交和杂种状态下的表达。在这项研究中，我们检查了各种转录本的杂交和近交个体（B73和Mo17），以确定是否特定的信使RNA的数量是加性或非加性的杂交种。此外，我们检查了杂交三倍体个体中相同转录本的水平，这些个体接受了不相等的基因组贡献，一个单倍体基因组来自一个亲本，两个来自另一个亲本。如果等位基因的表达仅仅是双亲杂种的加性值，则可以观察到中亲值。我们的研究表明，相当数量的基因不表现出中亲值的表达在杂种。相反，二倍体杂种中的转录水平与二倍体近交系中的水平负相关。虽然转录水平明显是非加性的，但三倍体杂交种的转录水平受基因组剂量的影响。
The molecular basis of hybrid vigor (heterosis) has remained unknown despite the importance of this phenomenon in evolution and in practical breeding programs. To formulate a molecular basis of heterosis, an understanding of gene expression in inbred and hybrid states is needed. In this study, we examined the amount of various transcripts in hybrid and inbred individuals (B73 and Mo17) to determine whether the quantities of specific messenger RNAs were additive or nonadditive in the hybrids. Further, we examined the levels of the same transcripts in hybrid triploid individuals that had received unequal genomic contributions, one haploid genome from one parent and two from the other. If allelic expression were merely the additive value in hybrids from the two parents, the midparent values would be observed. Our study revealed that a substantial number of genes do not exhibit the midparent value of expression in hybrids. Instead, transcript levels in the diploid hybrids correlate negatively with the levels in diploid inbreds. Although transcript levels were clearly nonadditive, transcript levels in triploid hybrids were affected by genomic dosage.