2018年1月3日，Plant Cell发表了题为“Genomic Imprinting was Evolutionarily Conserved during Wheat Polyploidization”的文章。该文章为中国农业大学辛明明教授研究组完成，揭示了印迹基因在小麦多倍体化过程中，表达模式的保守性。

基因印迹是指：正交和反交的当代种子中，来源于母本或父本的等位基因被特异沉默的现象。

基因组印迹是一种表观遗传现象，会导致基因据其亲本来源而差异表达。为了评估基因组印迹的进化保守性和倍性对这一过程的影响，我们通过高通量转录组测序研究了二倍体，四倍体和六倍体小麦胚乳中的原始亲本特异性基因在不同发育阶段的表达模式。我们分别在二倍体，四倍体和六倍体小麦中鉴定了91，135和146个母系或父系表达的基因（分别为MEG或PEG），其中52.7％在不同发育阶段表现出动态表达模式。GO富集分析表明，MEGs和PEGs分别参与代谢过程和依赖DNA的转录。在小麦六倍体化过程中，将近一半的印迹基因表现出保守的表达模式。此外，源自全基因组重复的40%的同源性对，在六倍体小麦的不同亚基因组中始终是母本或父本偏爱的。另外，分别在四倍体和六倍体小麦的基因组复制后发现，通过串联重复进化的同源对的印迹表达分别为41.2％和50.0％。这些结果表明，基因组印迹在是近亲物种Triticum和Aegilops之间的进化是保守的，面临这些属种间的多倍体杂交。

Genomic imprinting is an epigenetic phenomenon that causes genes to be differentially expressed depending on their parent-of-origin. To evaluate the evolutionary conservation of genomic imprinting and the effects of ploidy on this process, we investigated parent-of-origin-specific gene expression patterns in the endosperm of diploid (Aegilops spp.), tetraploid, and hexaploid wheat (Triticum spp.) at various stages of development via high-throughput transcriptome sequencing. We identified 91, 135, and 146 maternally or paternally expressed genes (MEGs or PEGs, respectively) in diploid, tetraploid, and hexaploid wheat, respectively, 52.7% of which exhibited dynamic expression patterns at different developmental stages. Gene ontology enrichment analysis suggested that MEGs and PEGs were involved in metabolic processes and DNA-dependent transcription, respectively. Nearly half of the imprinted genes exhibited conserved expression patterns during wheat hexaploidization. In addition, forty percent of the homeolog pairs originating from whole genome duplication were consistently maternally or paternally biased in the different subgenomes of hexaploid wheat. Furthermore, imprinted expression was found for 41.2% and 50.0% of homolog pairs that evolved by tandem duplication after genome duplication in tetraploid and hexaploid wheat, respectively. These results suggest that genomic imprinting was evolutionarily conserved between closely related Triticum and Aegilops species, and in the face of polyploid hybridization between species in these genera.