Morgan and his group found that when genes were grouped on the same chromosome, some genes were very hightly linked and showed-

Options

A. Very low recombination
B. Higher recombination
C. No recombination
D. `100%` parental combination

Answer

**Step-by-Step Solution:**

1. **Understanding Linkage:** Morgan and his group discovered that genes located on the same chromosome tend to be inherited together. This phenomenon is known as "linkage."

2. **Linkage and Recombination:** The degree of linkage between genes affects the recombination frequency. When genes are closely linked on the same chromosome, they are less likely to undergo recombination during meiosis.

3. **Recombination Process:** Recombination occurs during the pachytene stage of prophase I of meiosis, where homologous chromosomes can exchange genetic material. However, if genes are tightly linked, the chances of this exchange happening are reduced.

4. **Analyzing the Options:**
- **Very Low Recombination:** This option suggests that tightly linked genes will show minimal recombination, which aligns with Morgan's findings.
- **Higher Recombination:** This would imply that linked genes are more likely to recombine, which contradicts the concept of linkage.
- **No Recombination:** This suggests that recombination does not occur at all, which is not entirely true as some recombination can happen even among linked genes.
- **100% Parental Combinations:** This would mean that all offspring would only show parental traits without any variation, which is also not accurate since some recombination can occur.

5. **Conclusion:** Based on the understanding of linkage and recombination, the correct answer to the question is "very low recombination."

**Final Answer:** Very low recombination.

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