In 1989, Pellestor et al. (American Journal of Human Genetics 44:464-473) examined the chromosomal constitution of sperm cells from males who were heterozygous carriers of reciprocal translocations. From a male who was heterozygous for a der(4:17) reciprocal translocation, they reported the following data: Chromosome constitution of sperm cell cells Balanced, with no translocation Balanced, with der(4:17) translocation Adjacent 1 (unbalanced) Adjacent 2 (unbalanced) 15 O 20 O 30 What is the expected number of sperm cells in the sample that are balanced with the der(4:17) translocation? 40 Number of 45 16 19 21 4