Department of Biology and Zurich-Basel Plant Science Center, Swiss Federal Institute of Technology, ETH Centre, CH-8092 Zurich, Switzerland.
Trends Genet. 2010 Mar;26(3):142-8. doi: 10.1016/j.tig.2009.12.006. Epub 2010 Jan 19.
Polyploidization, a widespread phenomenon among plants, is considered a major speciation mechanism. Polyploid plants have a high degree of immediate post-zygotic reproductive isolation from their progenitors, as backcrossing to either parent will produce mainly nonviable progeny. This reproductive barrier is called triploid block and it is caused by malfunction of the endosperm. Nevertheless, the main route to polyploid formation is via unreduced gametes and unstable triploid progeny, suggesting that there are ways to overcome the triploid block. Until recently, the mechanistic basis for unreduced gamete formation and the triploid block were completely unknown. Recent developments have revealed genetic pathways leading to unreduced gamete formation as well as the underlying genetic basis for the triploid block in Arabidopsis. These novel findings will provide the basis for a genetic understanding of polyploid formation and subsequent speciation in plants.
多倍体化是植物中广泛存在的现象，被认为是主要的物种形成机制。多倍体植物与其祖先之间具有高度的即时合子后生殖隔离，因为回交到任一亲本都会产生主要的非存活后代。这种生殖障碍称为三倍体障碍，它是由胚乳功能障碍引起的。然而，多倍体形成的主要途径是通过未减数配子和不稳定的三倍体后代，这表明有办法克服三倍体障碍。直到最近，未减数配子形成和三倍体障碍的机制基础还完全未知。最近的研究揭示了导致未减数配子形成的遗传途径以及拟南芥中三倍体障碍的潜在遗传基础。这些新发现将为植物多倍体形成和随后的物种形成的遗传理解提供基础。
