CHROMOSOME BREAKAGE BY DIEPOXIDE AND BY X-RAYS 



{3) Some of the apparent chromosome breaks have their origin in chro- 

 matid interchange. 



(4) Dicentrics and centric rings are frequent after X-ray treatment, but 

 no evidence was found of chromosome reunion (R") after treatment with 

 diepoxide even at the long time-intervals. 



ACKNOWLEDGEMENTS 



/ am indebted to Professor P. C. Koller and to Dr. S. H. Revell for supplying me 

 with samples of diepoxide, to Dr. J. R. Clarkson for irradiating material and to 

 Mrs. J. Paton for invaluable assistance. This investigation is supported by grants 

 from the British Empire Cancer Campaign. 



REFERENCES 



1 Darlington, C. D. and La Cour, L. F. J. Genet. 1945, 46 180. 



2 Ford, C. E. Proc. 8th Intern. Cong. Genet., Heriditas Suppl. 1949, 570. 

 ^Thoday, J. M. Proc. 8th Intern. Cong. Genet., ibid, 1949, 672. 



* Thoday, J. M. Brit. J. Radiol. 1951, 24 572 and 622. 

 5 Gray, L. H. and Scholes, M. E. ibid, 1951, 24 82. 



« Revell, S. H. Brit. Ernp. Cancer Camp. Ann. Rep. 1953, 30 42. 



^ Revell, S. H. Symposium on Chromosome Breakage, Heredity Suppl. 1953, 107. 



* McLeish, J. Symposium on Chromosome Breakage, ibid, 1953, 125. 

 9 Darlington, C. D. and Koller, P. C. Heredity, 1947, 1 187. 



" Smith, H. H. and Lofty, T. A. Amer. J. Bat. 1954, 41 589. 

 " Darlington, C. D. John Innes Hart. Inst. Ann. Rep. 1952, 42 26. 

 12 Revell, S. H. Brit. Emp. Cancer Camp. Ann. Rep. 1954, 31 33. 

 1^ Revell, S. H. This Symposium. 

 1* Wood, R. K. S. Nature, Lond. 1951, 167 771. 



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