Ananda Chakrabarty received the first U.S. patent for a GM organism. This organism was
1. cloned E. coli
2. Dolly the cloned sheep
3. transgenic mouse expressing the growth hormone gene
4. Pseudomonas engineered to degrade petroleum

Detailed Explanation:
Correct Answer:
4. Pseudomonas engineered to degrade petroleum

The Pioneering Work of Ananda Chakrabarty

Ananda Chakrabarty made history in 1980 by becoming the first person to receive a U.S. patent for a genetically modified organism (GMO). His invention was a genetically engineered strain of the bacterium Pseudomonas, which was designed to degrade petroleum and other hydrocarbons. This genetically modified organism was capable of breaking down toxic oil spills, providing a groundbreaking solution for environmental cleanup.

Why Other Options Are Incorrect:

• Cloned E. coli (Option 1):
  While Escherichia coli is widely used in genetic engineering, the first patent issued to Chakrabarty was not for a genetically modified E. coli, but for a modified Pseudomonas strain capable of degrading petroleum.

• Dolly the Cloned Sheep (Option 2):
  Dolly was the first mammal to be cloned from an adult somatic cell, and this achievement was made in 1996, well after Chakrabarty’s patent. Dolly is not related to Chakrabarty’s work in genetic modification of microorganisms.

• Transgenic Mouse Expressing Growth Hormone Gene (Option 3):
  While transgenic mice have been widely used in research and are genetically modified organisms, Chakrabarty’s patent was for a bacterial strain, not a transgenic mouse.

Conclusion:

Ananda Chakrabarty’s Pseudomonas engineered to degrade petroleum was a major milestone in biotechnology, marking the first time a genetically modified organism was patented in the United States. This achievement opened doors to the potential for using GMOs in environmental applications, such as bioremediation, and had a lasting impact on both biotechnology and environmental science.