Blocking primers to enhance PCR amplification of rare sequences in mixed samples – a case study on prey DNA in Antarctic krill stomachs

Table 3 Results from fragment analysis showing the algae and krill peak height generated from PCR mixtures with different amounts of the different blocking primers added and different initial concentration of algal 28S rDNA fragments.

Initial concentration of Pyramimonas fragments to Euphausia fragments	Blocking primer	Amount of 10 μM blocking primer added	Peak height
			Fragment length 180 (Pyramimonas sp.)	Fragment length 199 (Euphausia superba)
1:100	No blocking	0 μL	311	8107
	Short28SR-	1.0 μL	8454	3030
		2.5 μL	8516	186
	blkKrill-3'c3	5.0 μL	8243	0
	Short28SF-	1.0 μL	8374	7538
		2.5 μL	8524	190
	DPO-blkKrill	5.0 μL	8498	66
1:1000	No blocking	0 μL	0	8301
	Short28SR-	1.0 μL	8480	6025
		2.5 μL	8470	146
	blkKrill-3'c3	5.0 μL	8617	0
	Short28SF-	1.0 μL	7740	8309
		2.5 μL	8427	318
	DPO-blkKrill	5.0 μL	8427	140
Krill only	No blocking	0 μL	0	8324

ISSN: 1742-9994