Determining which type of adventitious presence of transgenic traits test to request can vary depending on the end use of the information.  Testing should be adequate for product use and for the impact it has on future quality or use.  Species that are targeted particularly are corn, soybean, cotton, canola, rice, and alfalfa.  This article and accompanying chart will assist you in deciding appropriate testing strategies for testing for adventitious presence. 

There are a number of different technologies ranging from herbicide bioassays, enzyme linked immunosorbant assay (ELISA), and polymerase chain reaction (PCR) that can be utilized in determining the presence of adventitious presence in different seeds and grains.  Herbicide bioassay and ELISA tests react with the trait protein while PCR tests looks for inserted transgenic DNA.  Quantitative PCR is utilized with international shipments or food grade material. 

The following chart lists the procedure, what does it test, the benefits and limitations as well as the cost.  Give Kalyn a call to discuss these and she can assist in determining which test will meet your testing requirements.

Procedure	What Does it Test?	Benefits	Limitations	Cost
Herbicide Bioassay	§    Presence/absence of particular trait – Roundup Ready® (NK603, GA21), Liberty Link® (PAT)	§     Economical §    % trait or %  non-trait reported §    Can be combined with ELISA testing for economical AP Screen of 1200 or 2400 seeds	§    Seven day turn-around time §   Dead and dormant seed trait level not determined §    Test limited to herbicide traits	$20 - 40 for 1,200 and 2,400 seed tests
ELISA	§    Presence/absence and measurement of protein produced from inserted gene §    YG CB (Mon 810, Bt 11), YG CRW (Mon 863),    Soybean RR (CP4 EPSPS) §    StarLink (Cry9C) §    HerculexÔ (Cry1F)	§    2-3 day turnaround time   §    Can be combined with herbicide bioassay testing for economical AP screen of 1,200 or 2,400 seeds	§    Not Available for GA 21 (Roundup Ready® for corn)	$35-60/test for 1,200-2,400 seed tests
PCR Qualitative	§    Absence of 35S and NOS – common promoter and terminator of inserted transgenic DNA	§    Screens for all current non-regulated GMO traits with one test §    Sensitivity determined by number of seeds tested; 1,200 seeds- 0.4% or less, 10,000 seeds 0.05% or less §    4 day turnaround §    Capable of screening processed food and grain products	§    Expense	$130-225 for 1,200-10,000 seeds tested
PCR Semi-Quantitative	§    Looks for inserted transgenic DNA §    Estimates % GMO statistically from number of sub samples positive out of total sub samples	§    Screens for all present non-regulated GMO traits with one test §    Sensitivity determined by number of seeds tested; 1,200 seeds- 0.4% or less, 10,000 seeds- 0.05% or less §    4 day turnaround §    Capable of screening processed food and grain products	§    Expense	$150-240 for 1,200-10,000 seeds tested
PCR Quantitative	§    Looks for inserted transgenic DNA §    Determines % GMO from % GMO standard line	§    Screens for all current non-regulated GMO traits with one test §    Standards to 0.01% GMO level §    Sensitivity based on seeds tested –5,000 seeds –0.1%,10,000 seeds – 0.05% §    4 day turnaround	§    Expense	$250-275 for 5,000-10,000 seeds tested