The pyrithiamine or pPTR vectors are E. coli-Aspergillus shuttle vectors and contain an ampicillin resistance gene (AmpR) as the selection marker for E. coli and a pyrithiamine-resistance gene (ptrA) as the selection marker for Aspergillus. Pyrithiamine is a pyridine analog and inhibitor of thiamine. Because the pPTR vector multiple cloning site (MCS) is located within the lacZ region, the presence or absence of target DNA insert can easily be verified using blue/white screening via bacterial plates containing IPTG and X-Gal.