Changes Involving Genomes and Chromosomes I49 



18.6. Give a possible chromosomal formula for human individuals who are: 



a. Triploid males. 



b. Klinefelter's type of male. 



c. Mongolian idiot. 



d. Both b. and c. 



Which of these are trisomic diploid, tetrasomic diploid, doubly trisomic diploid? 

 Which are euploid, and explain? 



18.7. Discuss the statement: "All somatic cells from diploid zygotes are chromosomally 

 identical." 



18.8. Klinefelter's males and Mongolian idiots rarely have children. Each of these ab- 

 normalities occurs in about 0.2% of individuals at birth. What would you calculate 

 to be the minimal frequency of zygotes that are trisomic diploid for any chromosome? 



18.9. Do you suppose that the human species will benefit from the discovery that certain 

 members of it are trisomic? Explain. 



18.10. What are the advantages of autopolyploidy? of amphiploidy? 



18.11. What can you conclude about the mutational basis for Hexaptera from the fact that 

 its salivary gland chromosomes are apparently indistinguishable from normal? 



18.12. What genetic explanation can you offer for the fact, demonstrated in Figure 18-2, 

 that the seed capsule of the haploid Datura is smaller than that of the triploid? 



