Eukaryotic genes are called

Options

A. Split genes
B. Discontinuous genes
C. Continuous genes
D. Both 1 and 2

Answer

### Step-by-Step Solution:

1. **Understanding Eukaryotic Genes**:
- Eukaryotic genes are segments of DNA that code for proteins. They are found in organisms whose cells have a nucleus.

2. **Identifying Gene Structure**:
- Eukaryotic genes consist of coding regions called exons and non-coding regions called introns.

3. **Definition of Split Genes**:
- The term "split genes" refers to the presence of both introns and exons within the gene structure. This means that the gene is not continuous but is split into segments.

4. **Pre-mRNA Processing**:
- When a gene is transcribed, the initial RNA product (pre-mRNA) contains both introns and exons.
- To produce mature mRNA, the introns (non-coding regions) must be removed through a process called splicing, leaving only the exons (coding regions).

5. **Formation of Functional mRNA**:
- After splicing, the resulting mature mRNA is a continuous sequence of exons that can be translated into a functional protein by ribosomes.

6. **Conclusion**:
- Therefore, eukaryotic genes are referred to as "split genes" due to the presence of introns and exons. The correct answer to the question is option A: split genes.

### Final Answer:
Eukaryotic genes are called **split genes**.

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