Which of the following is not true regarding the transgenic animals ?

Options

A. Transgenic mice are being developed for use in testing the safety of vaccines before they are used on humans.
B. They are used to study complex factors involved in growth such as insulin-like growth factor .
C. Protein alpha - 1 antitrypsin is used for replacement therapy for individuals at risk from emphysema.
D. In `1997,` the first transgenic cow, Rosie, produced human protein beta lactalbumin enriched milk

Answer

To solve the question regarding which statement is not true about transgenic animals, we will analyze each statement provided in the options.

### Step-by-Step Solution:

1. **Understanding Transgenic Animals**:
- Transgenic animals are those that have had a foreign gene deliberately inserted into their genome. This is done through genetic engineering techniques. They are also referred to as genetically modified organisms (GMOs).

**Hint**: Remember that transgenic animals are created to express specific traits or produce certain proteins.

2. **Evaluating the Statements**:
- **Statement 1**: "They are being developed to test the safety of vaccines."
- This statement is true. Transgenic mice are often used in research to test the safety and efficacy of vaccines before they are administered to humans.

**Hint**: Think about the role of animal testing in vaccine development.

- **Statement 2**: "They are used to study complex factors involved in growth, like insulin-like growth factor."
- This statement is also true. Transgenic animals can be used to study various biological processes, including growth factors and their effects on physiology.

**Hint**: Consider how scientists use transgenic models to understand biological mechanisms.

- **Statement 3**: "Alpha-1 antitrypsin protein has been used for replacement in individuals suffering from emphysema."
- This statement is correct. Transgenic animals can produce therapeutic proteins like alpha-1 antitrypsin, which is used to treat emphysema.

**Hint**: Recall the importance of proteins produced by transgenic animals in medical treatments.

- **Statement 4**: "In 1997, the first transgenic cow was made, Rosie, which made milk enriched with human protein called beta-lactalbumin."
- This statement is misleading. While it is true that Rosie was a transgenic cow, the protein mentioned is incorrectly named. The correct name should be alpha-lactalbumin, not beta-lactalbumin.

**Hint**: Pay attention to the specifics of the proteins mentioned in relation to transgenic animals.

3. **Identifying the Incorrect Statement**:
- After evaluating all the statements, we find that the fourth statement contains an error regarding the name of the protein. Therefore, it is the incorrect statement about transgenic animals.

### Conclusion:
The statement that is not true regarding transgenic animals is the one that incorrectly names the protein produced by the transgenic cow Rosie. Thus, the answer is **Option D**.