In slpit genes, the coding sequences are called

Options

A. Exons
B. Cistrons
C. Introns
D. Operons

Answer

**Step-by-Step Solution:**

1. **Understanding Split Genes**: Split genes consist of coding and non-coding regions. The coding regions are the parts of the gene that are expressed and translated into proteins, while the non-coding regions do not code for proteins.

2. **Identifying Coding Sequences**: In split genes, the coding sequences are specifically referred to as "exons." Exons are the segments of DNA that are transcribed into mRNA and then translated into proteins.

3. **Recognizing Non-Coding Sequences**: The non-coding regions of split genes are called "introns." Introns are sequences that are transcribed into mRNA but are removed during the RNA splicing process before translation.

4. **Eliminating Incorrect Options**:
- **Systron**: This term is not commonly used in genetics and does not refer to coding sequences.
- **Intron**: As established, introns are non-coding regions, so this option is incorrect.
- **Operon**: An operon is a cluster of genes regulated together, not specifically a coding sequence.

5. **Conclusion**: Based on the definitions and explanations, the correct answer to the question is that in split genes, the coding sequences are called "exons."

**Final Answer**: The coding sequences in split genes are called **exons**.

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