Radiation effects of thymidine-2-C14 *1II. Chromosome aberrations caused by thymidine-2-C14 and thymine-2-C14 in the onion root tip
1956; Elsevier BV; Volume: 11; Issue: 2 Linguagem: Inglês
10.1016/0014-4827(56)90100-8
ISSN1090-2422
AutoresH. A. McQuade, Morris Friedkin, A ATCHISON,
Tópico(s)Garlic and Onion Studies
Resumo1. Chromosome aberrations were studied in onion root tips treated with thymidine 2-C14 and thymine 2-C14. Roots treated with radiothymidine gave significantly higher aberration frequencies than those treated with radiothymine. Chromosome aberrations increased with increasing exposure to radiothymidine; this was not the case with radiothymine. 2. Radiation effects of thymidine were studied because it is a precursor of DNA without diversion to any known cytoplasmic component including RNA. Thus a unique system is available for provoking intranuclear damage. Thymine enters the cell without becoming part of the DNA. 3. Experiments were designed to determine whether or not the main source of chromosome aberration in thymidine-C14 treated roots was the radiocarbon in the genetic material. Evidence for and against the hypothesis is presented. Additional approaches involving the use of more intensely radioactive thymine are outlined.
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