Doyle Jeff J, Flagel Lex E, Paterson Andrew H, Rapp Ryan A, Soltis Douglas E, Soltis Pamela S, Wendel Jonathan F
Department of Plant Biology, Cornell University, Ithaca, New York 14850, USA.
Annu Rev Genet. 2008;42:443-61. doi: 10.1146/annurev.genet.42.110807.091524.
Polyploidy is a common mode of evolution in flowering plants. The profound effects of polyploidy on gene expression appear to be caused more by hybridity than by genome doubling. Epigenetic mechanisms underlying genome-wide changes in expression are as yet poorly understood; only methylation has received much study, and its importance varies among polyploids. Genetic diploidization begins with the earliest responses to genome merger and doubling; less is known about chromosomal diploidization. Polyploidy duplicates every gene in the genome, providing the raw material for divergence or partitioning of function in homoeologous copies. Preferential retention or loss of genes occurs in a wide range of taxa, suggesting that there is an underlying set of principles governing the fates of duplicated genes. Further studies are required for general patterns to be elucidated, involving different plant families, kinds of polyploidy, and polyploids of different ages.
多倍体是开花植物中一种常见的进化模式。多倍体对基因表达的深远影响似乎更多是由杂交而非基因组加倍引起的。基因表达全基因组变化背后的表观遗传机制目前仍知之甚少；只有甲基化得到了较多研究，而且其重要性在不同多倍体中有所不同。遗传二倍体化始于对基因组合并和加倍的最早反应；而关于染色体二倍体化的了解则较少。多倍体使基因组中的每个基因都发生复制，为同源拷贝中功能的分化或分配提供了原材料。在广泛的分类群中都存在基因的优先保留或丢失现象，这表明存在一套潜在的原则来支配重复基因的命运。需要开展进一步研究以阐明涉及不同植物科、多倍体类型以及不同年龄多倍体的一般模式。
