pcr problem with genomic fly

[Danuta Maria Antosiewicz]

To anyone on the net who knows:
	
		I have been attempting to PCR a fragment on the Drosophila Simulans TRA gene with almost no luck.  My primers are both 17 bases long and they span a segment of about 800 bases.  I've tried many different annealing temperatures from 53 - 65 degrees Celsius, and have also tried different concentrations of genomic DNA,  I've run 25 cycles, 30 cycles, and 35 cycles, and I still can't get the damn thing to work.  Does anyone know anything I don't know about genomic fly DNA and the effective PCR of these DNA? 

 Please respond.  My email address is:  jalin at ucsd.edu    Thanks.