Nondisjunction during meiosis leads to aneuploidy. Which description best captures this process and a common outcome?

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Multiple Choice

Nondisjunction during meiosis leads to aneuploidy. Which description best captures this process and a common outcome?

Non-disjunction during meiosis means the chromosomes or chromatids fail to separate properly, producing gametes that carry an extra copy or are missing a copy of a chromosome. When such a gamete fuses with a normal gamete, the zygote ends up with an abnormal chromosome number—aneuploidy. A classic example is trisomy 21, where three copies of chromosome 21 lead to Down syndrome due to altered gene dosage across many genes. This error occurs in the germline during meiosis, not in somatic mitosis, and it often results in developmental consequences in the offspring.

Non-disjunction during meiosis means the chromosomes or chromatids fail to separate properly, producing gametes that carry an extra copy or are missing a copy of a chromosome. When such a gamete fuses with a normal gamete, the zygote ends up with an abnormal chromosome number—aneuploidy. A classic example is trisomy 21, where three copies of chromosome 21 lead to Down syndrome due to altered gene dosage across many genes. This error occurs in the germline during meiosis, not in somatic mitosis, and it often results in developmental consequences in the offspring.

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