In molecular markers, dominance and * * * dominance refer to PCR amplification products (DNA fragments) of alleles. Dominant markers, such as RAPD and ISSR, PCR products can not be accurately judged, and heterozygosity can not be distinguished. Only bands can be analyzed and recorded as 0/1; While * * * dominant markers such as SSR can distinguish heterozygotes, that is, they can show different variations in DNA of diploid and polyploid chromosomes, and can not only record and analyze 0/ 1 according to the length (bp) of amplified products, but also * * * dominant markers can distinguish heterozygotes, that is, if there are insertions, deletions and other variations at the same site on homologous chromosomes, even if.
Therefore, * * * dominant markers have greater advantages than dominant markers in revealing genetic diversity. More importantly, SSR primers are developed based on conserved exon sequences, that is, known DNA sequences, and have specific positions in the genome, so they are widely used in QTL analysis.