Martinez-Perez Enrique, Shaw Peter, Aragon-Alcaide Luis, Moore Graham
John Innes Centre, Colney, Norwich NR4 7UH, UK.
Plant J. 2003 Oct;36(1):21-9. doi: 10.1046/j.1365-313x.2003.01853.x.
Hexaploid wheat possesses 42 chromosomes derived from its three ancestral genomes. The 21 pairs of chromosomes can be further divided into seven groups of six chromosomes (one chromosome pair being derived from each of the three ancestral genomes), based on the similarity of their gene order. Previous studies have revealed that, during anther development, the chromosomes associate in 21 pairs via their centromeres. The present study reveals that, as a prelude to meiosis, these 21 chromosome pairs in hexaploid (and tetraploid) wheat associate via the centromeres into seven groups as the telomeres begin to cluster. This results in the association of multiple chromosomes, which then need to be resolved as meiosis progresses. The formation of the seven chromosome clusters now explains the occasional occurrence of remnants of multiple associations, which have been reported at later stages of meiosis in hexaploid (and tetraploid) wheat. Importantly, the chromosomes have the opportunity to be resorted via these multiple interactions. As meiosis progresses, such interactions are resolved through the action of loci such as Ph1, leaving chromosomes as homologous pairs.
六倍体小麦拥有源自其三个祖先基因组的42条染色体。根据基因顺序的相似性，这21对染色体可进一步分为七组，每组六条染色体（每个祖先基因组各有一对染色体）。先前的研究表明，在花药发育过程中，染色体通过着丝粒以21对的形式配对。本研究表明，作为减数分裂的前奏，六倍体（和四倍体）小麦中的这21对染色体在端粒开始聚集时通过着丝粒聚集成七组。这导致多条染色体配对，然后在减数分裂进行过程中需要解开。现在，七个染色体簇的形成解释了在六倍体（和四倍体）小麦减数分裂后期偶尔出现的多条配对残余物的现象。重要的是，染色体有机会通过这些多重相互作用重新排列。随着减数分裂的进行，这种相互作用通过诸如Ph1等基因座的作用得以解决，使染色体成为同源对。
