Freethought & Rationalism Archive

ps418 · 06-12-2003, 12:08 PM

There is a paper in a recent issue of the American Journal of Human Genetics demonstrating that intrachromosomal rearrangements can be used to quantify levels of exposure to densely ionizing radiation. In this case, they looked at chromosome 5 from white blood cells. Other points of interest are a new 'band painting' technique that makes the identification of such rearrangements much easier to detect, as well as the report that people exposed to DI radiation have large intrachromosomal rearrangements, greater than 6 million bases long. The paper itself can be download for free at coauthor D.J. Brenner's website:

Hande M.P., Azizova T.V., Geard C.R., Burak L.E., Mitchell C.R., Khokhryakov V.F., Vasilenko E.K. and Brenner D.J. Past exposure to densely ionizing radiation leaves a unique permanent signature in the genome. Am. J. Hum. Genet. 72:1162-1170 (2003).

Quote:

Speculation has long surrounded the question of whether past exposure to ionizing radiation leaves a unique permanent signature in the genome. Intrachromosomal rearrangements or deletions are produced much more efficiently by densely ionizing radiation than by chemical mutagens, x-rays, or endogenous aging processes. Until recently, such stable intrachromosomal aberrations have been very hard to detect, but a new chromosome band painting technique has made their detection practical. We report the detection and quantification of stable intrachromosomal aberrations in lymphocytes of healthy former nuclear-weapons workers who were exposed to plutonium many years ago. Even many years after occupational exposure, more than half the blood cells of the healthy plutonium workers contain large (>6 Mb) intrachromosomal rearrangements. The yield of these aberrations was highly correlated with plutonium dose to the bone marrow. The control groups contained very few such intrachromosomal aberrations. Quantification of this large-scale chromosomal damage in human populations exposed many years earlier will lead to new insights into the mechanisms and risks of cytogenetic damage.

See also:

Geiger counter in every human revealed

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