sentence: cDNA samples were used as templates in order to measure the basal level expression of the MAT1-1 , MAT1-2 , PREA , PREB , GPA1 , STE4 , STE18 , STE20 , STE50 , STE11 , STE7 , KSS1 , STE12 and α - pheromone genes in yeast and mycelium .