Two allelic genes are located on

Options

A. The same chromosome
B. Two homologous chromosomes
C. Two-non-homologous chromosomes
D. Any two chromosomes

Answer

### Step-by-Step Solution:

1. **Understanding Alleles**:
- Alleles are defined as the contrasting forms of a gene that occupy the same position (locus) on homologous chromosomes. For example, if a gene determines flower color, one allele may code for red flowers while another may code for white flowers.

2. **Identifying Chromosomes**:
- In the context of genetics, chromosomes are structures within cells that contain DNA and genes. Each organism typically has pairs of chromosomes, one inherited from each parent.

3. **Homologous Chromosomes**:
- Homologous chromosomes are pairs of chromosomes that have the same structure and gene sequence but may carry different alleles. For instance, one chromosome may carry an allele for blue eyes while its homologous partner may carry an allele for brown eyes.

4. **Meiosis and Crossing Over**:
- During meiosis, specifically in prophase I, homologous chromosomes can exchange genetic material in a process known as crossing over. This occurs between non-sister chromatids of homologous chromosomes, leading to genetic variation.

5. **Conclusion**:
- Therefore, the two allelic genes are located on **homologous chromosomes**. This means that each gene is found at the same locus on each chromosome of the homologous pair, but they may carry different alleles.