Afa家族串联重复序列因只出现在小麦及小麦族近缘属物种而得名,本研究从蒙古冰草中克隆得到一个Afa家族序列,长度为233 bp,命名为pAmAfa1,该序列在GENBANK中进行同源序列比对,结果表明该序列与大多数小麦族其他物种的Afa家族串联重复序列存在较高的相似性;系统进化分析表明,蒙古冰草pAmAfa1序列与大赖草pLrAfa3,pLrAfa5序列聚在一起,表明蒙古冰草P染色体组与大赖草的N、X染色体亲源关系较近。为了明确Afa家族串联重复序列在蒙古冰草染色体上的位置,双色荧光原位杂交技术被采用,以pAmAfa1为探针检测到杂交信号出现在染色体的末端或近端部的区域,每条染色体上都有杂交信号,表明Afa家族串联重复序列普遍存在于P染色体组中。
Tandem repetitive Afa-family sequences are known to occur in the wheat and related species of Triticeae. A member of the Afa-family sequences isolated from Mongolian Wheatgrass (Agropyron mongolicum Keng) (2n= 2x= 14,PP) is 233 bp, named as pAmAfal, which is most similar with other Afa-family sequences in Triticeae species. The phylogenic analysis results show that pAmAfal is clustered with pLrAfa3 and pLrAfa5, and the findings indicate that P genome has homology with N and X genomes. To know which the genome of Mongolian wheat- grass carries the Afa-family sequence; FISH is carried out using pAmAfal as the probe. The signals appear in the telomeric regions and subtelomeric regions of all chromosomes. This finding indicates that P genomes contain Afa-family repeats.