Abstract:

Through the sequence analysis of 2 548 ESTs in Betula pendula deposited in NCBI, we found that 306 SSRs were distributed in 260 ESTs out of 2 548 ESTs sequences, accounting for 10.2% of the whole EST sequences. The frequency of SSR was 12.01%, in which, the repetitive proportions of dinucleotide, trinucleotide, and tetranucleotide were 81.37%, 16.67%, and 1.96%, respectively. Moreover, the efficiency of primer design with various softwares was different. The software, Primer3, designed 176 pairs of SSR primers, the proportion of primers, which were successfully used for amplifying DNA fragments of B.platyphylla, was 59.09%, and the proportion of primers that produced polymorphic fragments was 25.96%. The software, SSR primer, designed 100 pairs of primers, the proportion of primers, which were successfully used for amplifying DNA fragments of B.platyphylla, was 37%, and the proportion of primers producing polymorphic fragments was 48.65%.

Key words: Betula pendula, Betula platyphylla, EST, SSR, marker