All genes located on the same chromosome

Options

A. form different groups depending upon their relative distance
B. form one linkage group
C. will not from any linkage groups.
D. form interactive groups that affect the phenotype.

Explanation

To solve the question regarding all genes located on the same chromosome, we can break it down step by step:

### Step-by-Step Solution:

1. **Understanding Genes on Chromosomes**:
- Genes are segments of DNA located on chromosomes. Each chromosome can carry multiple genes.

2. **Concept of Linkage**:
- Genes that are located on the same chromosome tend to be inherited together. This phenomenon is known as "linkage."

3. **Linkage Groups**:
- A linkage group consists of all the genes on a single chromosome. These genes are inherited as a unit during cell division.

4. **Separation of Genes**:
- Genes on the same chromosome do not separate during meiosis unless crossing over occurs. Crossing over is a process that can occur during meiosis where homologous chromosomes exchange segments, which can lead to the separation of linked genes.

5. **Distance Between Genes**:
- The closer two genes are on a chromosome, the less likely they are to be separated during crossing over. Therefore, genes that are physically close on the chromosome form a stronger linkage.

6. **Human Linkage Groups**:
- In humans, there are 23 pairs of chromosomes, which means there are 23 linkage groups. Each group corresponds to a pair of chromosomes.

7. **Conclusion**:
- Since all genes located on the same chromosome form one linkage group, the correct answer to the question is that they form one linkage group.

### Final Answer:
- All genes located on the same chromosome form one linkage group.