Kishii Masahiro, Tsujimoto Hisashi
Kihara Institute for Biological Research and Graduate School of Integrated Science, Yokohama City University, Yokohama, Japan.
Genome. 2002 Oct;45(5):946-55. doi: 10.1139/g02-059.
The TaiI family sequences are classified as tandem repetitive DNA sequences present in the genome of tribe Triticeae, and are localized in the centromeric regions of common wheat, but in the subtelomeric heterochromatic regions of Leymus racemosus and related species. In this study, we investigated the chromosomal distribution of TaiI family sequences in other Triticeae species. The results demonstrated a centromeric localization in genera Triticum and Aegilops and subtelomeric localization in other genera, thus showing a genus-dependent localization of TaiI family sequences in one or the other region. The copy numbers of TaiI family sequences in species in the same genus varied greatly, whether in the centromeric or subtelomeric regions (depending on genus). We also examined the evolution of TaiI family sequences during polyploidization of hexaploid common wheat. A comparison of chromosomal locations of the major TaiI family signals in common wheat and in its ancestral species suggested that the centromeric TaiI family sequences in common wheat were inherited from its ancestors with little modification, whereas a mixed origin for the B genome of common wheat was indicated.
Tail家族序列被归类为小麦族基因组中存在的串联重复DNA序列，位于普通小麦的着丝粒区域，但在总状披碱草及相关物种的亚端粒异染色质区域。在本研究中，我们调查了Tail家族序列在其他小麦族物种中的染色体分布。结果表明，Tail家族序列在小麦属和山羊草属中定位于着丝粒，而在其他属中定位于亚端粒，从而显示出Tail家族序列在这一个或另一个区域的属依赖性定位。同一属物种中Tail家族序列的拷贝数差异很大，无论是在着丝粒区域还是亚端粒区域（取决于属）。我们还研究了六倍体普通小麦多倍体化过程中Tail家族序列的进化。对普通小麦及其祖先物种中主要Tail家族信号的染色体位置进行比较表明，普通小麦着丝粒Tail家族序列从其祖先继承而来，几乎没有修饰，而普通小麦B基因组显示出混合起源。
