Question

A scientist is investigating genetic variation in chromosomes. The model below shows one way that meiosis can result in genetic variation.



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The scientist makes a claim that genetic variation in Example 1 above is a result of nondisjunction. Which evidence, from the model, BEST supports this claim?

A.
Homologous chromosomes separate incorrectly producing daughter cells with unequal amounts of genetic information.

B.
Heritable mutations caused by environmental factors result in loss of entire chromosomes.



C.
Deletions during DNA replication are passed to daughter cells.

D.
Homologous chromosomes exchange genetic material during meiosis.

Answer 1

A. Homologous chromosomes separate incorrectly producing daughter cells with unequal amounts of genetic information.

Explanation: Nondisjunction is the failure of homologous chromosomes (or sister chromatids) to separate properly during meiosis, producing gametes (and thus daughter cells after fertilization) with missing or extra chromosomes and unequal genetic content.