412 Intrachromosomal Aberrations 



2. Position effect has been observed in certain duplications. Is it 

 theoretically possible that it might be found as well in other chromo- 

 somal aberrations? Explain. 



3. If X-rays produce a small ring deficiency, show how the behavior 

 will differ if the ring has the centromere, if the centromere remains with 

 the rod-shaped segment of the .chromosome, and if the centromere splits 

 in half so that the ring has half and the rod has half. 



4. A man has two strains of a particular plant. One is homozygous 

 for the chromosome abode jghijklmn and the other is homozygous for the 

 chromosome ahcdejghilkjmn. Show the configurations in each of these 

 plants and in the hybrid between them. 



5. What would be the gametes of the hybrid in problem 4 if there 

 was (a) a single crossover within the inversion, (6) one crossover be- 

 tween the inversion and the centromere; (c) two crossovers within the 

 inversion involving all four strands; {d) one crossover in the inversion 

 and one between the inversion and the centromere; and (e) two cross- 

 overs in the inversion and one between the inversion and the cetro- 

 mere. 



6. Diagram the configurations in each part of problem 5 in the first 

 anaphase and second anaphase of meiosis. 



7. Diagram the configurations formed by each of the following pairs 

 of chromosomes: 



(a) abcdefghij and abedcfgihj 

 (6) abhgefdcij and abcdefghij 

 (c) abcdefghij and abfehgcdij 



8. A geneticist has a strain of plants two of whose chromosomes are 

 abcdefghij and klmnopqrst. He subjects them to X-rays and produces 

 a reciprocal translocation between these two chromosomes. The two 

 new chromosomes are abcdefghpqrst and klmnoij. Diagram the zygo- 

 tene configurations in the translocation heterozygote. 



9. What would be the offspring of the translocation heterozygote in 

 question 8? How would the chromosomes pair in each of the types of 

 offspring? 



10. In Datura quercifolia, three interchange types have been found 

 and have the following chromosomes: type 1 = 1-18, 3-4, 5-6, 7-20, 

 9-10, 11-21, 13-14, 15-16; 17-2, 19-8, 12-22, and 23-24; type 2 = 1-18, 

 3-4, 5-6, 7-20, 9-2, 11-21, 13-14, 15-16, 17-10; 19-8; 12-22, and 23-24; 

 type 3 = M8, 3-4, 5-6, 7-8, 9-10, 11-21, 13-14, 15-16, 17-2; 19-20; 

 12-22, and 23-24. What would be the chromosomal arrangement at 

 meiotic first prophase in the hybrids between type 1 and type 2, between 

 type 1 and type 3, and between type 2 and type 3? 



