Ocorrência de mutações em loci ligados ao cromossomo Y na prole nascida de indivíduos expostos à radiação ionizante
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Data
2009-05-13
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Universidade Federal de Goiás
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.
Descrição
Citação
ARRUDA, Jalsi Tacon. Occurrence of mutations in loci linked to Y chromosome in the offspring born to individuals exposed to ionizing radiation. 2009. 74 f. Dissertação (Mestrado em Ciências Biolóicas) - Universidade Federal de Goiás, Goiânia, 2009.