Zhuang Yan, Adams Keith L
University of British Columbia Botanical Garden and Centre for Plant Research, Department of Botany, University of British Columbia, Vancouver, British Columbia V6T1Z4, Canada.
Genetics. 2007 Dec;177(4):1987-96. doi: 10.1534/genetics.107.080325.
Hybridization between plant species can induce speciation as well as phenotypic novelty and heterosis. Hybrids also can show genome rearrangements and gene expression changes compared with their parents. Here we determined the allelic variation in gene expression in Populus trichocarpa x Populus deltoides F(1) hybrids. Among 30 genes analyzed in four independently formed hybrids, 17 showed >1.5-fold expression biases for one of the two alleles, and there was monoallelic expression of one gene. Expression ratios of the alleles differed between leaves and stems for 10 genes. The results suggest differential regulation of the two parental alleles in the hybrids. To determine if the allelic expression biases were caused by hybridization we compared the ratios of species-specific transcripts between an F(1) hybrid and its parents. Thirteen of 19 genes showed allelic expression ratios in the hybrid that were significantly different from the ratios of the parental species. The P. deltoides allele of one gene was silenced in the hybrid. Modes of gene regulation were inferred from the hybrid-parent comparisons. Cis-regulation was inferred for 6 genes, trans-regulation for 1 gene, and combined cis- and trans-regulation for 9 genes. The results from this study indicate that hybridization between plant species can have extensive effects on allelic expression patterns, some of which might lead to phenotypic changes.
植物物种之间的杂交可以诱导物种形成以及表型新奇性和杂种优势。与亲本相比，杂种还可能表现出基因组重排和基因表达变化。在这里，我们确定了毛果杨×美洲黑杨F(1)杂种中基因表达的等位基因变异。在对四个独立形成的杂种分析的30个基因中，17个基因在两个等位基因中的一个上表现出>1.5倍的表达偏差，并且有一个基因表现出单等位基因表达。10个基因的等位基因表达比率在叶和茎之间存在差异。结果表明杂种中两个亲本等位基因存在差异调控。为了确定等位基因表达偏差是否由杂交引起，我们比较了F(1)杂种与其亲本之间物种特异性转录本的比率。19个基因中的13个在杂种中的等位基因表达比率与亲本物种的比率显著不同。一个基因的美洲黑杨等位基因在杂种中被沉默。从杂种与亲本的比较中推断出基因调控模式。推断6个基因存在顺式调控，1个基因存在反式调控，9个基因存在顺式和反式联合调控。这项研究的结果表明，植物物种之间的杂交可能对等位基因表达模式产生广泛影响，其中一些可能导致表型变化。
