Affiliations: Department of Radiation Oncology
Tel: (409) 772-4244
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An mFISH image of a chromosome spread from a human peripheral lymphocyte that had been irradiated with 4 Gy 137Cs gamma-rays. Two simple, pairwise exchanges are seen, a dicentric involving chromosomes 1 and X (red arrows) and a translocation between chromosomes 12 and 21 (yellow arrows). Notably, the cell also contains a complex exchnage involving chromosomes 1, 2, 3, 9, 11 and 20 (white arrows). Image courtesy of B.D. Loucas and M.N. Cornforth.
Over the years, my research has focused on fundamental mechanisms of chromosome damage, principally that produced in mammalian cells following exposure to ionizing radiations. Studies are of considerable clinical relevance because they help us to understand how high doses of radiation can be more effectively used to kill cancerous cells in patients, and because they can help identify individuals that may be unusually sensitive to radiation treatment. Moreover, because radiation can also cause cancer, they are also important from the standpoint of radiation protection. Here, such research aids in determining the risks facing people that have been accidentally exposed to much lower doses radiation. Specific interests involve the relationship between mutations and chromosome aberrations in the context of radiation-induced genomic instability. Technical advances in cytogenetics are allowing us to more fully characterize the nature of radiation-induced rearrangements in the genome, thereby shedding light on the underlying recombinational processes. For example, we use the technique of combinatorial whole chromosome painting (mFISH) to investigate the formation of complex aberrations, complicated rearrangements that involve several different chromosomes and breakpoints produced from the same recombinational event. In collaboration with other labs, we have recently begun employing the strand-specific in situ hybridization technique of CO-FISH to study the recombination properties of mammalian telomeres, specifically the requirements of telomere binding factors and repair proteins for protective endcapping in newly synthesized telomeres.