中文摘要：

[目的]通过筛查猕猴桃EST数据库中的SSR重复序列,为开发出新型的猕猴桃EST-SSR标记和分子生物学研究奠定理论基础。[方法]从NCBI公共数据库中最新公布的猕猴桃表达序列标签（Expressed Sequence Tag,EST）中随机抽取56 400条序列,应用SSRHunter软件查找微卫星（Microsatellite,SSR）重复序列。搜索的标准是：二核苷酸、三核苷酸、四核苷酸、五核苷酸和六核苷酸最少重复次数分别为7次、5次、4次、4次、3次,包括复合型微卫星。微卫星的重复次数越多,相应的检验出等位基因数目就越多。[结果]从猕猴桃EST序列中获得了7 939条SSR,其中包括二核苷酸重复5 131条（64.63%）,三核苷酸重复1 237条（15.58%）,四核苷酸重复284条（3.58%）,五核苷酸重复397条（5.00%）,六核苷酸重复890条（11.21%）。大约每2.48 kb长度的单一基因序列中即存在1个SSR,即平均7个单一基因中存在1个SSR。在二核苷酸重复序列中,AG/CT共分布4 654条（90.70%）。在三核苷酸中,较为丰富的3种重复基元是ACC/GGT,AAG/CTT和CGC/GCG,共分布817条,它们占三核苷酸重复中各重复基元的66.04%。在其他基元中,还包括AGG/CCT,AGC/GCT,AAC/GTT,ATC/GAT,AGT/ACT,CGA/TCG,AAT/ATT7种重复基元,共420条SSR序列,占33.96%。AGT与CGT重复基元未见分布。[结论]在称猴桃EST序列中,二核苷酸重复序列是最丰富的重复单元,其次为三核苷酸重复和六核苷酸重复。在所获得的SSR重复单元中,AG/CT为优势重复。

英文摘要：

Objctive The aim was to make better use of the EST-SSR resources of kiwifruit for further molecular biological studies and new EST-SSR marker development by screening and mining the SSR repeats in the EST database of kiwifruit （Actinidia spp. ） [ Method] 56 400 of EST sequences were randomly selected from EST（ Expressed Sequence Tag）sequences of kiwifruit in the database of NCBI. EST sequences were analyzed and the SSR（Microsatellite） was screened by using the SSRHunter software. [ Result] 7 939 SSRs were identified from the ran- domly selected kiwifruit EST resources, among which there were 5 131 （64.63%） dinucleotide, 1 237 （ 15.58% ） trinucleotide, 284 （ 3.58% ） tetra nucleotide, 397 （5.00%） pentanucleotide and 890 （ 11.21% ） hexanucleotide SSRs. Among the dinucleotide sequences, AG/CT repeat motif was accounted for 4 654（90.70% ）. The frequency of SSRs was approximately 1/2.48 kb, which could exist to 1 SSR in 7 unigenes. [ Conclusion] The dinucleotide repeats appeared to be the most abundant SSRs, followed by the trinucleotide and hexanucleotide repeats. Among them the repeat motif such as AG/CT was predominant in each type of SSRs.