对NCBI网上公开的12757条茶树ESTs序列进行聚类,成功构建了茶树的独立基因(Unigene)数据库,发现茶树的EST序列冗余率约为68.2%。初步建立了茶树EST-SNP标记开发体系,明确了茶树EST中SNP的分布规律,茶树编码区的SNP发生频率约为0.58%,平均200bp就有1个SNP位点,并进一步推算出茶树基因组DNA序列的杂合率约为0.38%,平均300个碱基就可能出现1个杂合位点。从237个多基因聚类簇中发现了818个SNP候选位点,设计了25对SNP引物进行DNA重测序验证,发现EST-SNP候选位点的多态检出率为75%。
By clustering the 12757 ESTs of tea downloaded from NCBI, a unigene database of tea was successfully built. It was found that the redundancy rate for ESTs from tea was approximately 68.2%. An EST-SNP exploiting system for tea was established preliminarily. The SNP distribution was identified. The occurrence frequency for coding region SNP in tea was appropriately 0.58%. It meant that there was average one SNP in every 200bp of tea ESTs. Furthermore, the hybrid rate for tea genome was deduced to be 0.38%, averagely one hybrid DNA site per 300bp. Totally 818 candidated SNP were exploited from 237 multigene clusters. Then 25 pairs of SNP primers were designed and 75% of these sites were validated to be polymorphism by DNA sequencing.
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