Silkova O G, Shchapova A I, Kravtsova L A
Institute of Cytology and Genetics, Siberian Division, Russian Academy of Sciences, Novosibirsk, 630090 Russia.
Genetika. 2003 Nov;39(11):1505-15.
Meiosis has been studied in partially fertile wheat-rye F1 hybrids yielded by crosses Triticum aestivum (Saratovskaya 29 variety) x Secale cereale L. (Onokhoiskaya variety) (4x = 28). Hybrid self-fertility proved to be caused by formation of restituted nuclei, which appear after equational segregation of univalent chromosome in AI and sister chromatid non-separation in AII of meiosis, as well as after AI blockage in three different ways. Both types of meiotic restitution were found in each hybrid plant. Expression of the "meiotic restitution" trait varied significantly in polyhaploids of the same genotype (ears of the same plants, anthers of the same ear, microsporocytes of the same anther). Chromatin condensation in prophase proved to be related to the division type and univalent segregation in AI. During reduction segregation of univalents in AI, sister chromatid cohesion and chromosome supercondensation remained unchanged. The results obtained suggest that in the remote hybrids with haploid karyotype of the parental origin (polyhaploids), the program of two-stage meiosis may be fundamentally transformed to ensure one instead of two divisions. We propose that meiotic restitution is a result of special genetic regulation of the kinetochore organization (both structural and functional) and chromatin condensation, i.e. of major meiotic mechanisms.
对通过普通小麦（萨拉托夫斯卡亚29品种）×黑麦（奥诺霍伊斯卡亚品种）（4x = 28）杂交产生的部分可育小麦-黑麦F1杂种的减数分裂进行了研究。杂种的自育性被证明是由恢复核的形成引起的，恢复核出现在减数分裂AI期单价染色体的均等分离和AII期姐妹染色单体不分离之后，以及AI期以三种不同方式受阻之后。在每个杂种植物中都发现了这两种减数分裂恢复类型。“减数分裂恢复”性状在相同基因型的单倍体（同一植株的穗、同一穗的花药、同一花药的小孢子母细胞）中的表达差异很大。前期的染色质凝聚被证明与分裂类型和AI期的单价体分离有关。在AI期单价体的减数分裂分离过程中，姐妹染色单体的凝聚和染色体的超凝聚保持不变。获得的结果表明，在具有亲本来源单倍体核型的远缘杂种（单倍体）中，两阶段减数分裂程序可能会从根本上转变，以确保进行一次而不是两次分裂。我们认为减数分裂恢复是着丝粒组织（结构和功能）和染色质凝聚的特殊遗传调控的结果，即主要减数分裂机制的结果。
