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High production of nondisjunction mutants in the offspring of Drosophila melanogaster females exposed to carbon dioxide at meiosis I
Author(s) -
Fujikawa Kazuo,
Matsubara Masahiro,
Itoh Tetsuo,
Kondo Sohei
Publication year - 1998
Publication title -
environmental and molecular mutagenesis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 87
eISSN - 1098-2280
pISSN - 0893-6692
DOI - 10.1002/(sici)1098-2280(1998)31:2<176::aid-em10>3.0.co;2-9
Subject(s) - nondisjunction , biology , meiosis , genetics , offspring , andrology , aneuploidy , microbiology and biotechnology , chromosome , gene , medicine , pregnancy
Drosophila melanogaster females homozygous for X ‐linked recessive markers, y and w i , were exposed CO 2 and mated with y + w + / Y males. The progeny were sampled and inspected for y w i / y w i / Y ( XXY ) and y + w + / O ( XO ) mutants. The frequency of nondisjunction XXY mutants after a 90‐min exposure to CO 2 increased 100‐fold above the control level in the first‐day brood but did not increase above the control level in the second to sixth broods, showing that CO 2 is an extremely potent inducer of nondisjunction in mature oocytes during meiotic metaphase I but is not harmful to immature oocytes. Nondisjunction‐causing damage induced by CO 2 in mature oocytes disappeared completely within one day after CO 2 treatment, as evidenced by a reduction of the number of XXY mutants to the control level when the mating of CO 2 ‐treated females was delayed by one day. CO 2 ‐induced nondisjunction is probably due to damage to spindle microtubules in mature oocytes at metaphase I. N 2 is a less potent inducer of nondisjunction than CO 2 . Maternal X‐irradiation with 4 Gy did not induce XXY mutants, showing that medium‐level radiation does not induce nondisjunction. The results support Gaul den's hypothesis that oxygen deficits and CO 2 increases in the microenvironment of mature oocytes can be potent inducers of nondisjunction. The possible relationship to the cluster of Down syndrome seen in Berlin shortly after the Chernobyl accident is discussed. Environ. Mol. Mutagen. 31:176–182, 1998 © 1998 Wiley‐Liss, Inc.