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Testing for nondisjunction in the mouse

A C Chandley, R M Speed

    Environmental Health Perspectives
    |August 1, 1979
    PubMed

    Insights

    Spermatogonial irradiation in male mice significantly increased nondisjunction, while primary spermatocytes showed insensitivity to radiation and Mitomycin C. Female mice exhibited an "ageing effect" on nondisjunction, requiring further study for low-dose x-ray effects.

    Area of Science:

    • Reproductive biology
    • Genetics
    • Toxicology

    Background:

    • Nondisjunction, the failure of chromosomes to separate properly during cell division, can lead to aneuploidy and developmental abnormalities.
    • Understanding the factors that induce nondisjunction is crucial for assessing reproductive risks.
    • Mice are a common model organism for studying genetic toxicology and reproductive effects.

    Purpose of the Study:

    • To investigate the induction of nondisjunction in male and female mice by specific agents.
    • To determine the sensitivity of different germ cell stages to genotoxic agents.
    • To evaluate the influence of age and low-dose radiation on nondisjunction in females.

    Main Methods:

    • Karyotyping of 10-day fetal progeny from control and treated adult mice.
    • Exposure of male mice to 100 rad x-rays (affecting spermatogonia and primary spermatocytes) or Mitomycin C (affecting primary spermatocytes).
    • Exposure of female mice of different ages to 5 rad x-rays.

    Main Results:

    • Spermatogonial irradiation in males resulted in a 3.5-fold increase in nondisjunction.
    • Primary spermatocytes in males demonstrated insensitivity to both x-rays and Mitomycin C.
    • An "ageing effect" on nondisjunction was observed in female mice, but low-dose x-ray effects were inconclusive due to small sample size.

    Conclusions:

    • Spermatogonia are a sensitive target for radiation-induced nondisjunction in male mice.
    • Early primary spermatocytes are resistant to induced nondisjunction by the tested agents.
    • Female reproductive aging influences nondisjunction rates, warranting further investigation into low-dose radiation effects.

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