Liu Bao, Xu Chunming, Zhao Na, Qi Bao, Kimatu Josphert N, Pang Jinsong, Han Fangpu
Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics & Cytology, Northeast Normal University, Changchun 130024, China.
J Genet Genomics. 2009 Sep;36(9):519-28. doi: 10.1016/S1673-8527(08)60143-5.
A polyploid organism by possessing more than two sets of chromosomes from one species (autopolyploidy) or two or more species (allopolyploidy) is known to have evolutionary advantages. However, by what means a polyploid accommodates increased genetic dosage or divergent genomes (allopolyploidy) in one cell nucleus and cytoplasm constitutes an enormous challenge. Recent years have witnessed efforts and progress in exploring the possible mechanisms by which these seemingly intangible hurdles of polyploidy may be ameliorated or eventually overcome. In particular, the documentation of rapid and extensive non-Mendelian genetic and epigenetic changes that often accompany nascent polyploidy is revealing: the resulting non-additive and novel gene expression at global, regional and local levels, and timely restoration of meiotic chromosomal behavior towards bivalent pairing and disomic inheritance may ensure rapid establishment and stabilization as well as its long-term evolutionary success. Further elucidation on these novel mechanisms underpinning polyploidy will promote our understanding on fundamental issues in evolutionary biology and in our manipulation capacities in future genetic improvement of important crops that are currently polyploids in genomic constitution. This review is intended to provide an updated discussion on these interesting and important issues within the scope of a specific yet one of the most important plant groups-polyploid wheat and its related species.
多倍体生物通过拥有来自一个物种的两套以上染色体（同源多倍体）或两个或更多物种的染色体（异源多倍体）而具有进化优势。然而，多倍体如何在一个细胞核和细胞质中容纳增加的遗传剂量或不同的基因组（异源多倍体）是一个巨大的挑战。近年来，在探索改善或最终克服这些看似无形的多倍体障碍的可能机制方面已经做出了努力并取得了进展。特别是，新出现的多倍体常常伴随的快速而广泛的非孟德尔遗传和表观遗传变化的记录正在揭示：在全球、区域和局部水平上产生的非加性和新的基因表达，以及减数分裂染色体行为及时恢复为二价配对和二体遗传，可能确保其快速建立和稳定以及长期的进化成功。对这些支撑多倍体的新机制的进一步阐明将促进我们对进化生物学基本问题的理解，以及我们未来对基因组构成目前为多倍体的重要作物进行遗传改良的操作能力。本综述旨在在一个特定但最重要的植物类群——多倍体小麦及其相关物种的范围内，对这些有趣且重要的问题提供最新的讨论。
