Since the two dogs are carriers of the gene for deafness, their genotypes would be "Hh", where "H" is the dominant gene for normal hearing and "h" is the recessive gene for deafness. This means that each of the dogs has one copy of the normal hearing gene and one copy of the gene for deafness, but they have normal hearing because the dominant gene is masking the effect of the recessive gene. When these two dogs are mated, they can pass on either the normal hearing gene or the gene for deafness to their offspring. The genotype of the two parent dogs would therefore be "Hh".