Application Guide - QIAxcel Advanced

QIAxcel Advanced Application Guide 10/2016 95 Analysis limitations The identification of rice varieties was based on a database. A sample that generates a profile that is not present in the database cannot be identified. The 8 markers in this study were not sufficient to unambiguously identify all 15 Basmati rice varieties. In ambiguous cases, we used 2 additional markers to identify the variety (data not shown). When a sample consisted of 3 or more rice varieties, the allele patterns became complex (Figure 5), making complete sample identification and quantification difficult or at times, impossible. However, in most cases, identification and quantification could be done by independently analyzing grains that differ in physical characteristics (grain profiles). This method is more time-consuming and expensive, with an uncertainty between 6.5% for samples with >95% Basmati rice content and 22.2% for samples with lower Basmati rice content (average 14.1%). 82 bp 92 bp # Size (bp) NA NA % 1 15 0.0018099 n/a 2 82 0.0026379 75.86 3 92 0.0008393 24.10 4 600 0.0020555 n/a 82 bp 92 bp # Size (bp) NA NA % 1 15 0.0018099 n/a 2 82 0.0026379 75.86 3 92 0.0008393 24.10 4 600 0.0020555 n/a Figure 4. Quantification of the RM1 marker in a sample of 75% Taraori Basmati and 25% non-Basmati rice. The 82 bp peak comes from Basmati and the 92 bp peak from the non-Basmati rice. The normalized area percentage (NA %) of each peak represents the quantity of Basmati rice and adulterant, respectively. Figure 5. Analysis of a sample containing more than 3 rice varieties. A. Lane 1: RM1 + RM72. Lane 2: RM44 + RM55. Lane 3: RM202 + RM241. Lane 4: RM171 + RM348. B. Electropherogram of the RM1 and RM72 markers. C. Electropherogram of the RM171 and RM348 markers. With such complex allele patterns, identification requires additional analysis of physically different grains present in the sample. 1 2 3 4 156 bp 148 bp 360 bp 395 bp 421 bp 438 bp 167 bp 378 bp 79 bp 120 bp 170 bp 161 bp 267 bp 184 bp 194 bp 201 bp 1 2 3 4 156 bp 148 bp 360 bp 395 bp 421 bp 438 bp 167 bp 378 bp 79 bp 120 bp 170 bp 161 bp 267 bp 184 bp 194 bp 201 bp 1 2 3 4 156 bp 148 bp 360 bp 395 bp 421 bp 438 bp 167 bp 378 bp 79 bp 120 bp 170 bp 161 bp 267 bp 184 bp 194 bp 201 bp 1150.0018099 n/a 2820.002637975.86 3920.000839324.10 46000.0020555 n/a 1150.0018099 n/a 2820.002637975.86 3920.000839324.10 46000.0020555 n/a 1234 1234 1234

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