Analysis of B chromosome transcripts and their involvement in B chromosome nondisjunction

在某些植物中，驱动是B染色体的主要特征，特别是在禾本科植物中，它涉及到花粉有丝分裂时的定向不分离，并允许B染色体以比孟德尔频率更高的速度传递。然而，到目前为止，还没有任何B上的基因或非分离元件被描述为在B的积累机制/驱动中发挥作用。我们想要检测非编码RNA是否参与了B非析取的调节。为此，我们将分析位于B末端区域(控制不分离过程的染色体区域)的B特异转录活性高拷贝重复序列，以及迄今尚未确定特征的B特异转录本。此外，我们还打算通过A和B染色体染色质组成和着丝粒功能的差异，在微观水平上分析不分离的过程。这一分析将为高等真核生物产生快速基因组变化提供新的证据，特别是与自私染色体有关的变化，并将提高我们对染色体分离行为基础机制的了解。

Drive is the main feature of B chromosomes (Bs) in certain species of plants, especially the Gramineae, where it involves directed nondisjunction at pollen mitosis and allows the Bs to be transmitted at greater rate than Mendelian frequencies. Thus far however no gene, or nondisjunction element, on any B has yet been characterized that plays a role in B accumulation mechanisms/drive. We wish to test whether noncoding RNA is involved in the regulation of B nondisjunction. To this end Bspecific transcriptionally active high-copy repeats, which are located at the Bterminal regions (the chromosomal region which controls the process of nondisjunction), will be analyzed, together with with the hitherto uncharacterized Bspecific transcripts. In addition, we intend to analyse the process of nondisjunction at the microscopic level, in terms of differences in the chromatin composition, and centromere function between A and B chromosomes. This analysis will provide new evidence of the generation of rapid genome changes in higher eukaryotes, with particular relevance to selfish chromosomes, and will improve our knowledge of the mechanism underlying the segregation behaviour of chromosomes.