Questions and Problems 143 



6. In Drosophila, gray body (E) is dominant over ebony (e) and red 

 eye {Ca) over claret (ca). A cross between a heterozygous gray red and 

 an ebony claret gave 108 graj^ red : 47 gray claret : 41 ebony red : 104 

 ebony claret. Calculate x" and determine goodness of fit to a 1 : 1 : 1 : 1 

 ratio. 



7. If X- in question 6 is too large, what does it signify? How can 

 you explain the results obtained? 



8. In Capsella, A produces elongated, pointed primary leaf lobes, 

 whereas a produces blunt, shorter primary lobes; B divides the leaf by 

 deep sinuses, usually reaching nearly or quite to the midrib, whereas b 

 produces only shallow sinuses. An AA BB plant is crossed with an aa bb 

 plant. What are the genotypes and phenotypes of the Fi and F2 and 

 of the backcross of the Fi to the double recessive? 



9. In Capsella, AB plants are known as heteris, Ab as tenuis, aB as 

 rhomboidea, and ab as simplex. What are the phenotypes of the Fi and 

 F2 of the following crosses: heteris, homozygous for both genes X tenuis, 

 homozygous for A; homozygous heteris X homozygous rhomboidea; 

 homozygous tenuis X simplex; homozygous rhomboidea X simplex? 



10. What are the genotypes of the offspring of the following Capsella 

 crosses: AAbbXAABb; aaBbxAabb; AAbbXaaBB; AABbX 

 AaBb? 



11. In Drosophila melanogaster, black body {bl) is recessive to gray 

 {Bl) and spineless (ss) is recessive to spined (Ss). If a homozygous 

 black spineless is mated with a homozygous gray spined, what are the 

 genotypes and phenotypes of the Fi and F2? 



12. What are the genotypes and phenotypes of the backcross of the 

 Fi of question 11 to each parent and of the testcross of the Fi to a 

 black spineless fly? 



13. In Drosophila, normal wing (Vg) is dominant to vestigial (vg) and 

 red eye (P) is dominant to pink (p). What are the genotypes of flies 

 which produce the following types of offspring when crossed: (a) 83 

 normal red : 30 normal pink : 28 vestigial red : 9 vestigial pink; (6) 

 167 normal red : 53 normal pink; (c) 156 normal red : 59 normal 

 pink : 114 vestigial red : 109 vestigial pink; (d) 310 normal red : 318 

 normal pink : 105 vestigial red : 110 vestigial pink; (c) 68 normal 

 red : 24 normal pink : 71 vestigial red : 27 vestigial pink? Calculate x^ 

 in each part of this problem. 



14. In Drosophila, white eye (w) is recessive to red (T^) and is in 

 the sex chromosome; vestigial wing (vg) is recessive to normal (Vg) 

 and is in an autosome. What are the genotypes and phenotypes of 

 the Fi and F2 from the following crosses: WW VgVg X wY vgvg; 

 WW vgvg X wY VgVg ; irw VgVg X WY vgvg; ww vgvg X WY VgVg? 



