Gene and Point Mutations 



203 



Lewis John Stadler {1896-1954) is 

 noted for his studies on the nature of 

 mutation and of t/ie gene {see p. xi). 

 He and H. J. Muller discovered inde- 

 pendently the mutagenic effect of X 

 rays. {By permission of Genetics, Inc., 

 vol. 41, p. 1, 1956.) 



23.4. Would you expect the mutation rate to Polydactyly, P, from normal, p, to be greater 

 among normal individuals in a pedigree for Polydactyly than it is among normals in 

 general? Explain. How might you proceed to test this hypothesis? 



23.5. Do the mutational properties discussed suggest any limitations with respect to the 

 chemical composition of genes? Explain. 



23.6. When a chromosome is broken, is the breakage point within a gene or between genes, 

 or can both occur? Justify your answer. 



23.7. Point mutations are sometimes called gene mutations. Do you think this is per- 

 missible? Why? 



23.8. In what way is the study of mutation dependent upon genes? In what way is the 

 reverse true? 



23.9. What is your opinion with regard to the validity of applying principles of point muta- 

 tion directly to gene mutation? 



