Which of the following is not true for sister chromatids?

Options

A. They arise by replication during S phase
B. They segregate from each other during each mitotic anaphase
C. They usually contain identical versions of the same genetic information
D. They segregate from each other during meiosis I.

Answer

To determine which statement is not true for sister chromatids, we need to analyze the properties and behavior of sister chromatids during the cell cycle, particularly during mitosis and meiosis.

### Step-by-Step Solution:

1. **Understanding Sister Chromatids**:
- Sister chromatids are identical copies of a single chromosome that are formed during the S phase of the cell cycle when DNA is replicated. Each chromosome consists of two sister chromatids joined at a region called the centromere.

2. **Identifying True Statements**:
- **Statement 1**: "They arise in S phase."
- This statement is true. Sister chromatids are formed during the S phase when the DNA is replicated.

- **Statement 2**: "They segregate from each other during mitotic anaphase."
- This statement is also true. During mitosis, specifically in anaphase, sister chromatids are pulled apart to opposite poles of the cell.

- **Statement 3**: "They usually contain identical versions of the same genetic information."
- This statement is true as well. Sister chromatids are exact copies of each other, containing the same genetic information.

3. **Analyzing the Fourth Statement**:
- **Statement 4**: "They segregate from each other during meiosis I."
- This statement is not true. During meiosis I, homologous chromosomes (not sister chromatids) are separated. Sister chromatids remain together until meiosis II, where they are finally segregated.

4. **Conclusion**:
- The statement that is not true for sister chromatids is: "They segregate from each other during meiosis I."

### Final Answer:
The statement that is not true for sister chromatids is: **"They segregate from each other during meiosis I."**

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