522 



THE PRINCIPLES OF HEREDITY 



large numbers of 

 cross between two 



6. What are the expected types of offspring from a cross between a heterozy- 

 gous black, short-haired guinea pig and a homozygous white, long-haired guinea pig? 

 Show how you derive your answer. 



7. How can the inheritance of quantitative characters be explained on the basis 

 of the gene concept? 



8. Why are genetic ratios more reliable when there are 

 offspring? 



9. By means of a diagram show the expected results of a 

 roan short-horned cattle. 



10. Under what conditions are two genes said to be linked? 



11. What is the possible biological value of crossing over? 



12. What is the relation between hormones and chromosomes in sex determina- 

 tion in the vertebrate animals? 



13. How does sex determination in birds differ from that in man? 



14. Show the types of children that will be expected to result from a marriage 

 of a color-blind woman with a normal-visioned man. 



15. A normal man marries a normal woman who has a father with hemophilia. 

 Show the kinds of children which may be expected. 



