A diploid strain of yeast that was trisomic for a chromosome carrying the Trp1 gene was sporulated. When the asci were dissected and tested for the ability to grow without tryptophan, some asci had 4 prototrophic spores and some asci had 2 prototrophic spores and 2 auxotrophic spores. What was the genotype of the diploid trisomic parental strain with respect to the Trp1 gene?