Question

if these four cells resulted from cell division of a single cell with diploid chromosome number 2n = 4, what best describes what just occurred?

1. normal meiosis
2. translocation
3. inversion
4. nondisjunction

Explanation:

• Normal meiosis: Results in gametes with \(n\) chromosomes. Here, some gametes have \(n + 1\) or \(n-1\), so it's not normal meiosis.
• Translocation: Involves the transfer of genetic material between non - homologous chromosomes. This is not related to the change in chromosome number shown (\(n+1\), \(n - 1\)).
• Inversion: Reverses the order of genes on a chromosome. It doesn't cause a change in chromosome number like \(n+1\) or \(n - 1\).
• Nondisjunction: Occurs when chromosomes fail to separate properly during cell division. This can lead to gametes with an extra chromosome (\(n + 1\)) or a missing chromosome (\(n-1\)).

Answer:

1. nondisjunction