When the maternal and paternal chromosomes carry different alleles at the same locus, the genotype is called

Options

A. Homozygous
B. Heterozygous
C. Heterokont
D. Heterokaryotic

Answer

To solve the question, we need to understand the definitions of the terms related to alleles and genotypes. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Question
The question asks about the genotype when maternal and paternal chromosomes carry different alleles at the same locus.

### Step 2: Define Key Terms
1. **Alleles**: Different forms of a gene that can exist at a specific locus on a chromosome.
2. **Locus**: The specific location of a gene on a chromosome.

### Step 3: Identify the Types of Genotypes
- **Homozygous**: This term describes a genotype where both alleles at a locus are the same (e.g., AA or aa).
- **Heterozygous**: This term describes a genotype where the alleles at a locus are different (e.g., Aa).
- **Heterocont**: This term is not commonly used in genetics and refers to a different context (e.g., unequal lengths of flagella in certain organisms).
- **Heterokaryotic**: This term refers to cells that contain two or more genetically different nuclei within a common cytoplasm.

### Step 4: Analyze the Given Information
Since the question specifies that the maternal and paternal chromosomes carry different alleles, we are looking for a term that describes this condition.

### Step 5: Conclusion
The correct term for a genotype where the maternal and paternal chromosomes have different alleles at the same locus is **heterozygous**.

### Final Answer
The genotype is called **heterozygous**.

---