Purification of crime scene DNA extracts using centrifugal filter devices

Investigative Genetics

Table 2 Centrifugal filter purification of mock crime scene DNA extracts using Amicon Ultra 30 K and Microsep 30 K

Sample type	DNA purification	Average DNA concentration (ng/μL) with CV (%)	Detected STR alleles (>50 rfu)	Average of total sum of STR peak heights (rfu)^awith CV (%)	Average of intra-locus balance (0 to 1)^b	Average of inter-loci balance (0 to 1)^c
Blood on denim (n = 3)	None	0.46 (27%)	96%	30,776 (20%)	0.83	0.90
	Microsep 30 K	0.22(12%)	100%	42,113 (10%)	0.87	0.96
	Amicon Ultra 30 K	0.27(15%)	96%	51,596 (38%)	0.84	0.95
Blood on kitchen paper (n = 10)	None	0.32 (79%)	N/A	N/A	N/A	N/A
	Microsep 30 K	0.23 (83%)	100%	20,230 (78%)	0.89	0.99
	Amicon Ultra 30 K	0.23 (85%)	100%	21,115 (96%)	0.90	0.99
Hair (n = 10)	None	0.66 (77%)	N/A	N/A	N/A	N/A
	Microsep 30 K	0.39 (77%)	98%	32,135 (77%)	0.88	0.98
	Amicon Ultra 30 K	0.72 (55%)	100%	62,670 (56%)	0.93	0.99
Rape case samples, semen fraction (n = 24)	None	1.10 (34%)	N/A	N/A	N/A	N/A
	Microsep 30 K	0.56 (43%)	100%	57,088 (37%)	0.89	0.98
	Amicon Ultra 30 K	0.86 (25%)	100%	85,441 (23%)	0.91	0.99
Rape case samples, epithelial fraction (n = 24)	None	1.09 (51%)	N/A	N/A	N/A	N/A
	Microsep 30 K	0.68 (39%)	100%	33,498 (47%)	0.87	0.97
	Amicon Ultra 30 K	0.89 (30%)	100%	42,508 (30%)	0.88	0.97
Saliva on envelope (n = 3)	None	0.083 (22%)	100%	53,754 (14%)	0.90	0.98
	Microsep 30 K	0.050 (8%)	100%	43,682 (10%)	0.91	0.99
	Amicon Ultra 30 K	0.054 (17%)	100%	63,168 (6%)	0.88	0.99
Touch stains (mini-tape) (n = 10)	None	0.023 (71%)	N/A	N/A	N/A	N/A
	Microsep 30 K	0.027 (55%)	95%	11,281 (73%)	0.74	0.96
	Amicon Ultra 30 K	0.024 (59%)	97%	12,207 (77%)	0.76	0.96

^aTotal sum of peak heights have been normalized against the sample volume in PCR. ^bMean local balance, that is, the mean of the heterozygote balances in all markers of the electropherograms, was used for calculation of intra-locus balance. ^cNormalized Shannon entropy [32, 33] was used to calculate inter-locus balance. CV, Coefficient of variation; rfu, Relative fluorescence units.

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