Effect of flanking sequences of the DXS10103 locus on allele typing
The DNA of the two samples was amplified by PCR using the GSTARTM 30X and AGCU X19 commercial kits,respectively,and it was found that the genotyping of the two kits was different at the DXS10103 locus,with a difference of 2 base pairs.After analyzing the sequence information of DXS10103 locus,it was found that there is a repeat sequence of[CA]from base 48 to base 29 at the 5′ end upstream of the core repeat sequence.After high-throughput sequencing detection,2-base[CA]insertion was found in the repetitive structure of the flanking sequence.The positioning of the forward primer in the GSTARTM 30X kit was strategically located near the core sequences,effectively preventing any interference from the[CA]repeated sequence in the surrounding sequence.In contrast,the AGCU X19 kit amplification region included a repeat structure of the[CA]dinucleotide,a 2-base insertion was detected in the two samples,and stutters due to the repeat structure of the flanking sequence were detected.A similar situation also exists for the D21S1270 locus.Based on the findings in this study,when designing primers for the locus,it is recommended to avoid repetitive sequences in the flanking regions to prevent the occurrence of mutations in the flanking sequences and the resulting effects of stutter.
Core repeat sequencesDXS10103Flanking sequencesShort tandem repeats