Jenczewski Eric, Eber Frédérique, Grimaud Agnès, Huet Sylvie, Lucas Marie Odile, Monod Hervé, Chèvre Anne Marie
UMR ENSAR-INRA, Station de Génétique et Amélioration des Plantes, F-35653 Le Rheu, France.
Genetics. 2003 Jun;164(2):645-53. doi: 10.1093/genetics/164.2.645.
Precise control of chromosome pairing is vital for conferring meiotic, and hence reproductive, stability in sexually reproducing polyploids. Apart from the Ph1 locus of wheat that suppresses homeologous pairing, little is known about the activity of genes that contribute to the cytological diploidization of allopolyploids. In oilseed rape (Brassica napus) haploids, the amount of chromosome pairing at metaphase I (MI) of meiosis varies depending on the varieties the haploids originate from. In this study, we combined a segregation analysis with a maximum-likelihood approach to demonstrate that this variation is genetically based and controlled mainly by a gene with a major effect. A total of 244 haploids were produced from F(1) hybrids between a high- and a low-pairing variety (at the haploid stage) and their meiotic behavior at MI was characterized. Likelihood-ratio statistics were used to demonstrate that the distribution of the number of univalents among these haploids was consistent with the segregation of a diallelic major gene, presumably in a background of polygenic variation. Our observations suggest that this gene, named PrBn, is different from Ph1 and could thus provide complementary information on the meiotic stabilization of chromosome pairing in allopolyploid species.
精确控制染色体配对对于赋予有性繁殖多倍体减数分裂稳定性进而生殖稳定性至关重要。除了小麦中抑制部分同源配对的Ph1位点外，对于有助于异源多倍体细胞学二倍体化的基因活性了解甚少。在油菜（甘蓝型油菜）单倍体中，减数分裂中期I（MI）的染色体配对数量因单倍体来源的品种而异。在本研究中，我们将分离分析与最大似然法相结合，以证明这种变异是基于遗传的，并且主要由一个具有主要效应的基因控制。从一个高配对品种和一个低配对品种（在单倍体阶段）之间的F(1)杂种产生了总共244个单倍体，并对它们在MI期的减数分裂行为进行了表征。似然比统计用于证明这些单倍体中单价体数量的分布与一个双等位基因主要基因的分离一致，推测是在多基因变异的背景下。我们的观察结果表明，这个名为PrBn的基因与Ph1不同，因此可以提供关于异源多倍体物种中染色体配对减数分裂稳定化的补充信息。
