query in pcr genotyping

[kaushikvedam]

i am new to this technique pcr.
we are working with the hsp knock out mouse in our lab.when we breed these mouse we need to genotype them. we got the primers pair for hsf gene (which produce hsp) from invitrogen.
to confirm the mouse to be heterozygous or homozygous knockout mouse we also got primers for neo gene.
the vendor from whom we got these mouse told us that for a homozygous knockout offspring we should see a band in neo;for hetrozygous knockout mouse we should see band in both hsf and neo ;and for wild type mouse with hsp proteins we should see a band only in hsf.
my pcr protocol works for all my wild type samples and i get a band in hsf,which says my hsf primer works.but when ever i do the pcr with knock out mouse samples i dont see any band...i am confused now..i dont know whether these knock out mouse are homozygous or hetrozygous...please help me how to solve this problem.