Which of the following is not the feature of meiosis?

Options

A. Meiosis involves two sequential cycles of nuclear and cell division, meiosis I and meiosis II but only a single cycle of DNA replication.
B. Meiosis I is initiated after the parental chromosomes have replicated to produce identical sister chromatids at the S-phase.
C. Meiosis involves pairing of non-homologous chromosomes and recombination between them.
D. Four haploid cells are formed at the end of meiosis II.

Explanation

To determine which of the following is not a feature of meiosis, we need to analyze each statement provided in the question.

1. **Meiosis involves two sequential cycles of nuclear and cell division, meiosis I and meiosis II, but only a single cycle of DNA replication.**
- This statement is true. Meiosis consists of two main stages (meiosis I and meiosis II), and DNA replication occurs only once before meiosis I.

2. **Meiosis I is initiated after the parental chromosomes have replicated to produce identical sister chromatids at the S phase.**
- This statement is also true. Meiosis I begins after the DNA has been replicated during the S phase of the cell cycle, resulting in sister chromatids.

3. **Meiosis involves pairing of non-homologous chromosomes and recombination between them.**
- This statement is false. In meiosis, homologous chromosomes pair up, not non-homologous chromosomes. Recombination (crossing over) occurs between homologous chromosomes during prophase I.

4. **Four haploid cells are formed at the end of meiosis II.**
- This statement is true. The end result of meiosis II is the formation of four haploid cells from the original diploid cell.

Based on the analysis, the statement that is not a feature of meiosis is the third one: "Meiosis involves pairing of non-homologous chromosomes and recombination between them."

### Step-by-Step Solution:
1. **Identify the statements related to meiosis.**
- Read each statement carefully to understand what they imply about the process of meiosis.

2. **Evaluate the first statement.**
- Confirm that meiosis does involve two cycles of division and only one cycle of DNA replication. This is true.

3. **Evaluate the second statement.**
- Check if meiosis I starts after DNA replication. This is true.

4. **Evaluate the third statement.**
- Analyze the claim about pairing non-homologous chromosomes. This is false; meiosis involves homologous chromosomes.

5. **Evaluate the fourth statement.**
- Confirm that meiosis results in four haploid cells. This is true.

6. **Conclude which statement is incorrect.**
- Identify that the third statement is the one that is not a feature of meiosis.