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Dolly (sheep)

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Dolly was a female Finn-Dorset sheep who became one of the most famous animals in history. Born on 5 July 1996, she was the first mammal to be cloned from an adult somatic cell. A somatic cell is a regular cell taken from a specific part of a mature body. This achievement was a massive breakthrough in biology. It proved that a specialized cell could be reprogrammed to create an entirely new individual. Before Dolly, scientists were not sure if a mature cell could ever become a whole animal again.

Dolly clone
Dolly clone

To create Dolly, scientists used a process called somatic cell nuclear transfer. This method involves several precise steps. First, researchers took a nucleus from a cell in a mammary gland. The nucleus acts as the control center containing the DNA instructions. Next, they took an unfertilized oocyte, which is a developing egg cell, and removed its own nucleus. The donor nucleus was then inserted into this empty egg cell. To jumpstart the process, the scientists used an electric shock to stimulate the cell to divide. Once the cell developed into a blastocyst, it was implanted into a surrogate mother to grow into a lamb.

Dolly clone
Dolly clone

Dolly's creation was a team effort involving many experts. She was cloned by Ian Wilmut, Keith Campbell, and their colleagues at the Roslin Institute in Scotland. This work was part of the University of Edinburgh and involved a biotechnology company called PPL Therapeutics. The project received funding from PPL Therapeutics and the Ministry of Agriculture. While Dolly was a sensation, she was not the very first animal cloned. This type of work built on the 1958 research of John Gurdon. He had successfully cloned African clawed frogs using a similar approach with adult cells.

Dolly face closeup
Dolly face closeup

Dolly lived her entire life at the Roslin Institute in Midlothian. She was a productive mother and had six lambs in total. Her first lamb, Bonnie, was born in April 1998. In 1999, she had twins named Sally and Rosie. In 2000, she gave birth to triplets named Lucy, Darcy, and Cotton. However, Dolly faced some health challenges as she aged. In late 2001, she developed arthritis, which made walking difficult. She was treated with anti-inflammatory drugs to help her manage the pain.

Dolly face closeup
Dolly face closeup

Dolly passed away on 14 February 2003 at the age of six. She was euthanized due to severe arthritis and a progressive lung disease. A post-mortem examination identified the disease as ovine pulmonary adenocarcinoma, also known as Jaagsiekte. This is a form of lung cancer caused by a retrovirus called JSRV. Some people speculated that her cloning caused her early death. They pointed to her short telomeres, which are parts of chromosomes that often shorten as animals age. However, scientists at the Roslin Institute found no evidence that her cloning caused her illness. They noted that other sheep in the same flock also died from the same disease.

Dolly face closeup
Dolly face closeup

The legacy of Dolly extends far beyond her own life. Her success led to major advancements in stem cell research. This includes the discovery of induced pluripotent stem cells, which can grow into any tissue in the body. Since her birth, many other large mammals have been cloned, including pigs, deer, horses, and bulls. In 2018, scientists even successfully cloned a primate species, the macaque monkey. Cloning is also being studied as a way to save endangered species. For example, scientists once tried to clone the Pyrenean ibex, a mountain goat that was declared extinct in 2000.

Dolly face closeup
Dolly face closeup

Today, Dolly remains a symbol of scientific possibility. Her body was preserved through taxidermy by the Roslin Institute. It was donated to the National Museum of Scotland in Edinburgh. She has been a regular exhibit there since 2003. Through her, the world learned how cells can be reprogrammed to restart the journey of life. Her story continues to influence how we study genetics and the building blocks of living things.

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File:Dolly clone.svg
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File:Dolly face closeup.jpg
Dolly face closeup.jpg
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