Explanation:
These engineered cells will mate with each other or with normal mating type a cells, but not with normal mating type α
The sexual cell types of yeast are designated a and α, which are correspondingly conferred by the MATa and MATα alleles of the mating type locus (MAT)
Cells of opposite type can mate to establish a cell of the MATα/MATa diploid state because both MAT alleles are co-dominant, such diploid cells are sterile but can undergo meiosis and sporulation to form asci, each of which contains two MATa and two MATα haploid spores
