1) Duchenne Muscular Dystrophy (DMD) is an X-linked recessive trait that causes muscular weakness, deterioration of muscle tissue, and loss of coordination. The allele for DMD is represented by Xd and the normal allele is represented by XD. Neither parent has DMD, but both of their sons express the trait. What are the genotypes of the parents? 2) A chicken with the sex chromosomes ZW is female, and ZZ is male. Which gamete determines the offsprings sex and why?.