Version	1	/	Date	of	Issue:	10.29.15	/	Issuing	Authority:	Forensic	Science	Standards	Board	(FSSB)

OSAC	Research	Needs Assessment Form

Title	of	research	need:

Keywords:

Submitting subcommittee(s): Date	Approved:

(If	SAC	review	identifies	 additional	

subcommittees,	add	them	to	the	box	above.)

Background	information:

1.	 Description	of	research	need:

Characterizing,	designing	and	constructing	integrated	DNA	mixture	

interpretation	solutions	

Forensic	DNA	mixtures,	signal	processing,	artifacts,	DNA	interpretation,	low	

template	DNA,	complex	DNA	mixtures

BDIRC 8/25/16

Despite	recent	advances	in	the	development	and	construction	of	probabilistic	interpretation	systems	for	

complex	DNA	mixtures,	transitioning	these	systems	into	the	forensic	DNA	pipeline	is	still	a	challenge.	The	

solution	to	this	barrier	to	transition	still requires	breakthroughs	in	signal	analysis	that	come	from	innovative	

basic	and	applied	research	that	looks	beyond	the	analysis	and	interpretation	schemes	currently	known.	

In	many	cases	the	construction	of	current	probabilistic	systems	includes	algorithms	that	evaluate	allele	peak	

heights	and	stutter.		However,	DNA	signal	is	complicated	by	additional	elements	such	as	pull-up,	spikes,	

noise,	incomplete	adenylation,	dye	dissociation	and	raised	baseline.		These	artifactual	elements	originate	

from	a	variety	of	sources,	but	in	general,	can	be	classified	as	PCR- or	instrument- based	artifacts.		In	order	to	

create	a	DNA	interpretation	mechanism	that	is	fully	automated	and	objective,	improvements	in	signal	

analysis	and	signal	processing	are	required.		Further,	if	artifacts	continue	to	confound	DNA	signal	then	

implementation	of	processes	and	algorithms	that	appropriately	filter,	or	interpret, this	signal	is	warranted.		

An	example	of	pioneering	work	in	this	area	includes (1)	where	an	integrated	mathematical	approach	to

model	the	data is	developed.		One	major	advantage	of	this	method	is	the	correction	of	raised	baseline.				

Other	work	has	focused	on	implementing	interpretation	strategies	that	utilize	the	entire	signal	(2,	3).		

Though	there	is	evidence	to	suggest	that	the	information	gained	–particularly	for	low-template	DNA	

components- can	be	substantive	(4,	5),	a	decrease	in	the	analytical	threshold exacerbates	issues	associated	

with	artifact	interpretation.		Thus,	as	laboratories	and	researchers	continue	to	explore	the low	signal	regions	

of	the	evidence,	improved	mechanisms	to	analyze	and	interpret	the	signal	are	needed.		
Version	1	/	Date	of	Issue:	10.29.15	/	Issuing	Authority:	Forensic	Science	Standards	Board	(FSSB)

2.	 Key	bibliographic	references	relating	to	this	research	need:

3a.		In	what	ways	would	the	research	results	improve	current	laboratory	capabilities?

(1) Goor	R.,	et	al.		A	Mathematical	Approach	to	the	Analysis	of	Multiplex	DNA	Profiles.		Bull	Math	Biol.	

2011	Aug; 73(8):	1909-1931.

(2) Perlin	M.,	et	al.	Linear	Mixture	Analysis:	A	Mathematical	Approach	to	Resolving	Mixed	DNA	Samples.	

J	Forensic	Sci.	2001;	46(6):	1372-1378.

(3) Swaminathan	H.,	et	al.		CEESIt:	A	Computational	Tool	for	the	Interpretation	of	STR	Mixtures.		

Forensic	Sci	Int:	Genetics.	2016;	22:	149-160.

(4) Rakay	CA., et	al. Maximizing	Allele	Detection:	Effect	of	analytical	threshold	and	DNA	levels	on	Rates	

of	Allele	and	Locus	Drop-out.	Forensic	Sci	Int:	Genetics.	2012;	6:	723-728.

(5) Taylor	D.,	et	al.	Does	the	Use	of	Probabilistic	Genotyping	Change	the	Way	We	Should	View	Subthreshold	data?	Australian	J	Forensic	Sci.	2015;	Dec.

Extensive	research	over	the	last	two	decades	has	yet	to	produce	a	fully	objective	and	automated	

DNA	interpretation	system.		Some systems	rely	upon	the	laboratory	to apply	a	signal	threshold

during	analysis,	while	others	require	artifact	filtering,	assumptions	on the	number	of	contributors,	

and/or	inputs	for	allele	drop-in	or	drop-out.		Even	in	instances	where	the	signal	may	be	

unencumbered	by	multiple	contributors,	degradation	or	low-template	levels,	DNA	signal	

interpretation	is	still	a	necessity.		Further,	as	the	quantity	of	data	continues	to	grow,	automated	

signal	interpretation	and	processing	will	become	more	of	a	necessity	since signal	noise	and	artifact	

will	necessarily	be	present.		Thus,	mechanisms	by	which	the	signal	can	be	evaluated	in	an	objective	

manner	will	be	required,	regardless	of	platform.
Version	1	/	Date	of	Issue:	10.29.15	/	Issuing	Authority:	Forensic	Science	Standards	Board	(FSSB)

3b.		In	what	ways	would	the	research	results	improve	understanding	of	the	scientific	basis	for	the	

subcommittee(s)?

3c.		In	what	ways	would	the	research	results	improve	services	to	the criminal	justice	system?

4.		Status assessment	(I,	II,	III,	or	IV):		

This	research	need	has	been	identified	by	one	or	more	subcommittees	of	OSAC	and	is	being	provided	as	an	

informational	resource	to	the	community.

Major gap	

in	current	

knowledge

Minor gap	

in	current	

knowledge

No	or	limited

current	research	

is	being	

conducted

I III

Existing current	

research	is	being	

conducted

II IV

As	the	level	of	DNA	information	generated	by	laboratories	grows (i.e.	additional	loci,	NGS	data)

manual	interpretation	of	profiles	containing	noise,	artifacts,	and	true	signal	will	become	more	

challenging.		Thus,	there	is	a	need	for	DNA	processing	to	approach	automation. .		Though	there	will,	

presumably,	always	be	a	need	for	laboratories	to	review	the	data,	this	research	will	allow for	

simultaneous	improvements	in	signal	detection	and	interpretation.		If	both	detection	and	

interpretation	are	normalized,	then	the	rapidly	developing	science	of	DNA	mixture	interpretation	

can	be	effectively	communicated	to	stakeholders alleviating	concerns	related	to	"black	box"	

approaches.

This	research	will provide	data	and	develop	research	products	to	examine	and	minimize	variations

that	occur	during	mixture	interpretation.		If	they	are	minimized,	it	is	anticipated	that	this	research

can	be	transitioned	more	easily	to	the	forensic	laboratory,	resulting	in	a	standardized	approach	to	

mixture	interpretation that	can	be	effectively	communicated	to	stakeholders.

II
Version	1	/	Date	of	Issue:	10.29.15	/	Issuing	Authority:	Forensic	Science	Standards	Board	(FSSB)

// Approval	date:

(Approval	is	by	majority	vote	of	subcommittee.		Once	approved,	forward	to	SAC.)

1.		Does	the	SAC	agree	with	the	research	need?				Yes					X 							No							⃝		

2.		Does	the	SAC	agree	with	the	status assessment?				Yes				X			⃝							No							⃝	

If	no,	what	is	the	status assessment	of	the	SAC:

Approval	date:

(Approval	is	by	majority	vote	of	SAC.		Once	approved,	forward	to	NIST	for	posting.)

Subcommittee 04/29/2016

SAC

08/24/2016