There are certain sequences of DNA that are termed as mobile or jumping genes and are useful as vectors. Such sequences are called as

Options

A. YAC
B. Plasmid
C. Transposons
D. Phasmid

Answer

To solve the question, we need to identify the correct term for certain sequences of DNA that are referred to as mobile or jumping genes and are useful as vectors. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Question
The question asks for the name of DNA sequences that are mobile or jumping genes and can be used as vectors.

**Hint:** Think about the definitions of mobile genetic elements and their roles in genetic engineering.

### Step 2: Analyze the Options
We have four options to consider:
1. **YAC (Yeast Artificial Chromosome)** - These are engineered chromosomes derived from yeast, not mobile genes.
2. **Plasmid** - These are small, circular DNA molecules found in bacteria, but they are not classified as jumping genes.
3. **Transposons** - These are sequences of DNA that can move around to different positions within the genome of a single cell, often referred to as "jumping genes."
4. **Phasmid** - This term refers to a type of stick insect and is not related to DNA sequences.

**Hint:** Focus on the definitions and functions of each option to determine which one fits the description of mobile genes.

### Step 3: Identify the Correct Answer
From the analysis:
- **Transposons** are indeed the sequences that are known as mobile or jumping genes. They can move within the genome and are often used in genetic engineering as vectors.

**Hint:** Recall that transposons can insert themselves into various locations in the genome, which is why they are considered "mobile."

### Conclusion
The correct answer to the question is **Transposons**.

**Final Answer:** Transposons