I designed a primer for gene sequence(1480 bp) and when carried PCR, the product was 150 bp, what is the problem? and how to obtain the correct fragment?
If your primes and template are designes from genomic dna then it may have some secondary structure and the enzyme could be reading across a looped dna giving a short product. Try amplifying with 1m betaine (final concentration) and/or 6%dmso or if your colleagues have any highGC buffer for their polymerase try using this as it will rmove a lot of secondary structure. If your gene has pseudogenes than it may be necessary to re design the primers