动物中多倍体虽不常见，但癌细胞常是多倍体和非整倍体。多倍体是植物基因组进化和农作物驯化的一个重要途径；小麦、棉花、油菜都是异源多倍体，由种间杂交经染色体组加倍后形成的。多倍体农作物的驯化和利用是中国和世界粮食安全的重要基础。更多的植物包括有些动物是古多倍体，多倍化后保存了大量的同源基因。在稳定的异源多倍体中，种间杂种优势被永久的固定，并为自然和人工选择提供了新基因和互作的遗传资源。然而，有关多倍体分子进化和遗传机制仍然很不清楚。本课题将利用新形成和自然的拟南芥多倍体为研究材料，对多倍体基因组和表观基因组开展研究；揭示出表观基因图谱包括DNA甲基化，小RNA和组蛋白修饰对部分同源基因的表达、调控网络和形态性状的影响；比较和解释DNA分子进化、基因计量、突变率和表观基因组之间的相互关系；找到调控进化和功能变化的分子机理；为更好地利用多倍体动植物提供新的思路。

Although polyploidy is rare in animals, polyploidy and aneuploidy are often associated with cancer cells. In contrast, polyploidy is an important feature for the evolution of many plant genomes and for the domestication of agricultural crops； wheat, cotton, and oilseed rape are allopolyploids, which are formed by interspecific hybridization followed by chromosome doubling. Thus，improvement of polyploid crops should have provided a foundation for food security in the world. Many more plant species including some animals are known as paleopolyploids that contain many duplicate genes. In stable allopolyploids, heterozygosity and heterosis is permanently fixed, and the gene and subgenomic interactions provide molecular bases for natural and artificial selection. However, molecular and evolutionary mechanisms for polyploidy are poorly understood. This project will investigate genomic, epigenomic, and phenotypic changes in resynthesized and natural Arabidopsis polyploids. Specifically, the effects of gene dosage, DNA methylation, histone modifications, and small RNAs will be tested on expression of homoeologous genes and regulatory networks; the relationship between epigeneome, sequence variation, dosage，and mutation rates will be determined; mechanisms for genome evolution and phenotypic variation will be investigated. The results will provide molecular bases for improving plant and animal production.