Ocorrência de mutações em loci ligados ao cromossomo Y na prole nascida de indivíduos expostos à radiação ionizante / Occurrence of mutations in loci linked to Y chromosome in the offspring born to individuals exposed to ionizing radiation

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

In September 1987, in Goiânia-GO, Brazil, one of the most serious radiological accidents occurred at a radiotherapy unit involving a source of cesium-137. An area of 2,000 m2 was contaminated and 249 people were exposed, both externally and internally, to substantial doses of ionizing radiation, resulting in four fatalities due to acute radiation syndrome. The current study examined the occurrence of possible mutations in the Y chromosome of the exposed men and their male offspring divided into two groups: A) eight accidentally exposed men and eight boys; B) twelve occupationally exposed men and sixteen boys; and the control group with 8 men and 8 boys not exposed. DNA was isolated from peripheral blood lymphocytes and 30 loci (SRY, AMELY, ZFY, AZFa-Prox1, SY83, AZFa-Prox2, SY86, SY85, SY84, USP9Y, SY87, DBY, AZFa-Dist1, 12f2, AZFa-Dist2, UTYpe, SY106, SY124, SY127, SY134, SY135, SY143, SY1197, SY1291, SY1125, SY1054, YDAZ3, SY254, SY255, RH65618) were amplified by the polymerase chain reaction. All DNA tests had a probability of paternity of at least 99.99%. All analyzed individuals amplified STS; however, 4 fathers (8.4%) and 8 sons (21.2%) in group A, and 3 fathers (7.1%) and 3 sons (63.3%) in group B showed mutations. The total mutation rates were 0.11. The first generation of the accidentally exposed group showed 7 mutations in SY86, 12 mutations in SY84, and 1 mutation both in 12f2 and SY135. The first generation of the occupationally exposed group showed 2 mutations in SRY, AMELY, AZFa-Prox1, AZFa-Prox2, SY86, SY85, SY84, USP9Y, SY87, AZFa-Dist1, UTYpe, SY106, SY124, SY127, SY134, SY135, SY143, SY1125, SY1054, YDAZ3, SY254, SY255, and RH65618; and 4 mutations in 12f2. In the control group, only one son showed an SY84 deletion. Recombination events between repetitive regions are possibly the cause of the high incidence of de novo mutations in the Y chromosome. The mutations were possibly generated by intrinsic mechanisms that could have been increased by the ionizing radiation from cesium-137. The exposure to ionizing radiation from cesium-137 can be detected in offspring of exposed individuals, and the mutation rate can be attributed to radioactive exposure.

ASSUNTO(S)

3. ionizing radiations 1. recombinação; 2. cromossomo y; 3. radiação ionizante; 4. césio 137- goiânia (go) 2. y chromosome 4. cesium-137 2. cromossomo y 1. recombination biologia molecular 1. recombinação 3. radiação ionizante 4. césio-137

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