It is my idea:

when do not have +ve (in case that our restriction enzyme cuts our desire gene during digestion):

after amplification desire gene,   pcr product may use without restriction enzyme in one tube as a +ve and others with restriction enzyme as a normal test and one can be as a -ve with restriction enzyme without pcr product , results, cutting DNA strand in tubes with restriction enzymes and no cutting in the tube not including restriction produced same bands as a pcr products, her we can notify that restriction enzymes work well.

Thanks Sheik Asraf S and Edel Pérez-López for answers.

Thanks Kamaran, I think it is a good idea, I will give a try. Just to ask here one important thing: if the restriction enzyme cuts in one position, does that digest result (band) should has the same bp as the pcr product (gene) before digestion?

if the RE cuts in one position, 2 fragments will produce and it shouldnt has the same bp as the pcr product because pcr product is the full gene you have amplified and then you want to digeste it and cut it by RE so if the RE cuts the gene in one or more position donot produce the same band bp as the pcr products

this is what i said before this is to genotyping without using +ve instead used undigested (pcr product)

Can you send the full paper please?

used nested pcr

Thanks.