甜瓜基因组SSR位点分布规律与多态性初探

Distribution and Polymorphism Characteristics of SSR Loci in Melon Genome

以3个甜瓜品种"BM7"、"伽师瓜"和"Y8"为试材,选取甜瓜基因组的3个DNA区域进行SSR位点的分布规律分析,进一步通过聚丙烯酰胺凝胶电泳检验甜瓜基因组SSR位点的多态性,以期初步揭示甜瓜基因组中SSR位点的分布规律及其多态性,进而为甜瓜及其它物种开展相关研究提供参考。试验表明:甜瓜基因组中平均每1.9kb就有一个SSR位点,富含A和T的重复基序出现的频率远高于富含C和G的重复基序的频率,没有发现全部由C、G构成的重复基序;二、三、四碱基重复基序的SSR位点占绝大多数(83.3%),五、六碱基重复基序的SSR位点分布较少(16.7%)。二、三、四、五、六核苷酸重复基序SSR位点平均长度依次为21、15、14、16、20bp。设计的82对SSR引物中81对扩增出产物,多态比例最高为48.1%。试验表明,甜瓜基因组中SSR分布具有一定规律,并且可以利用SSR分子标记开展相关研究;试验同时对更好地开展SSR和ISSR分子标记的相关研究奠定了理论基础和依据。

Taking three kinds of melon including ‘BM7＇, ‘Jiashi＇ and ‘Y8＇ as materials, three fragments of the melon genome sequence were randomly selected for investigation of distribution characteristics of SSR in melon genome; polyacrylamide gel electrophoresis was used to test the polymorphism of self designed SSR primers. The results showed that the mean distribution density of SSR was one SSR loci per 1.9 kh. Motif rich in A and T appears much higher than motif rich in C and G, motif comprised all by C and/or G was not found. The largest proportion of SSR loci was the dinucleotide,trinucleotide and tetranucleotide repeat motifs,and the total ratio was 83. 3 %. The proportion of pentanucle- otide and hexanucleotide was low,with the ratio of 16. 70%. The average lengths of dinucleotide to hexanucleotide repeat motifs were 21,15,14,16,20 bp respectively. The PCR products can be amplified by 81 of total 82 designed self designed SSR primers successfully, and the maximal polymorphism was 48.1%. The results showed that the distribution of SSR in melon genome was relative stable,and it is helpful for future work in SSR and ISSR.