Application of degenerate oligonucleotide primed PCR (DOP-PCR) for SNP discovery in soybean

Abstract

As the majority of methods for single nucleotide polymorphism (SNP) identification are highly cost-prohibitive, it is necessary to develop new strategies that are more suitable for small and medium-scale laboratories. In this paper, we investigate the potential of degenerate oligonucleotide primed PCR (DOP-PCR) for SNP discovery in soybean. PCR fragments were amplified from two soybean cultivars, ‘Pureunkong’ and ‘Jinpumkong 2,’ shotgun cloned and sequenced. The sequences of both cultivars were then assembled and examined for occurrence of SNPs. The effectiveness of SNP discovery was much lower than expected. Over 1,300 analyzed sequences were grouped in 144 contigs, but only 51 putative SNP sites were found in 18 of these contigs. About 50% of the contigs contained identical sequences and in more than one-third (35.4%), putative paralogous fragments were assembled. Subsequent validation of SNPs allowed the confirmation of only eight SNP sites. The failure to validate the remaining SNPs was mostly due to amplification of duplicated or multiplicated genomic regions. A relatively high proportion of chloroplast and mitochondrial DNA sequences was another limitation of effective SNP detection. Although the DOP-PCR technique was not efficient enough for SNP discovery because of the degree of soybean genome complication, the relatively large number of paralogous sequences in our data collection can be used for further detailed analysis of the genome structure of this species.