If the egg of sexually reproduction organisms contains 16 chromosomes, what will be the number of dyads in anaphase l?

Options

A. 16
B. 8
C. 32
D. 64

Answer

To solve the problem, we need to understand the process of meiosis, particularly focusing on anaphase I.

### Step-by-Step Solution:

1. **Understanding Chromosome Number in Egg Cells**:
- The question states that the egg of the organism contains 16 chromosomes. This number represents the haploid (n) number of chromosomes.

2. **Meiosis Overview**:
- Meiosis consists of two rounds of cell division: meiosis I and meiosis II. During meiosis I, homologous chromosomes are separated, while during meiosis II, sister chromatids are separated.

3. **Formation of Dyads**:
- In anaphase I of meiosis, homologous chromosomes (which are in pairs) are separated. Each pair of homologous chromosomes is referred to as a dyad.
- Before anaphase I, during prophase I, the chromosomes replicate, resulting in each chromosome consisting of two sister chromatids.

4. **Calculating the Number of Dyads**:
- Since the original number of chromosomes is 16 (haploid), during the S phase of interphase (before meiosis begins), the chromosomes are replicated. This means there are now 32 chromatids present (16 chromosomes x 2).
- However, in anaphase I, we are dealing with the separation of homologous pairs. Each pair of homologous chromosomes (dyad) consists of 2 sister chromatids.
- Therefore, the number of dyads in anaphase I is equal to the original number of chromosomes, which is 16.

5. **Conclusion**:
- The number of dyads in anaphase I is 16.

### Final Answer:
The number of dyads in anaphase I is **16**.

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