Cheryll Tickle facts for kids

Cheryll Anne Tickle (born 18 January 1945) is a British scientist. She is famous for her work in developmental biology. This field studies how living things grow and develop. Dr. Tickle especially researched how the limbs (like arms and legs) of animals develop from a tiny egg. She is now a professor at the University of Bath.

Becoming a Scientist: Education and Early Career

Cheryll Tickle studied at the University of Cambridge. She earned her master's degree there in 1967. Later, she received her PhD from the University of Glasgow in 1970.

After her studies, Dr. Tickle worked as a researcher at Yale University in the United States. She then became a lecturer and professor at different universities in London. These included the Middlesex Hospital Medical School and University College London. In 1998, she moved to the University of Dundee. She became a special professor there in 2000. In 2007, she joined the University of Bath.

Understanding How Limbs Grow

Dr. Tickle's main research area is developmental biology. She wanted to understand how a single fertilized egg grows into a complete new individual. This process is called embryogenesis.

How Cells Organize Themselves

Early in her career, Dr. Tickle became interested in "cell sorting." Imagine you mix different types of cells. Cell sorting is how these cells then arrange themselves into organized structures. She studied this by taking cells apart and putting them back together. She wanted to see how they would naturally organize themselves again.

After her PhD, she worked at Yale University. She studied cell sorting in fish embryos. Later, she focused on how cells organize during the development of chicken limbs. She believed that if cells were mixed randomly, they would still arrange themselves into a proper pattern.

The Secrets of Limb Development

Scientists had found that two key areas are important for limb growth. These are the apical ectodermal ridge (AER) and the zone of polarizing activity (ZPA). The AER is a rim along the developing limb. The ZPA helps control how the limb develops from front to back.

Dr. Tickle focused on the ZPA. She wanted to know how it guided the growth of a limb. Her mentor, Lewis Wolpert, suggested that the ZPA releases a special chemical called a morphogen. This morphogen creates a "concentration gradient." This means there's more of the chemical closer to the ZPA and less further away. Cells at different distances would get different amounts of the chemical. This information would tell them what part of the limb to become.

Experiments with Chicken Wings

Dr. Tickle's experiments on chicken wings supported this idea. She found that the type of "digit" (like a finger or toe) that developed depended on its distance from the ZPA. Cells closest to the ZPA would form one type of digit. Cells further away would form a different type. For example, cells closest to the ZPA formed chicken digit 4. Cells furthest away formed chicken digit 2. This showed how the ZPA helps shape the limb.

Discovering Key Chemicals for Growth

In 1976, another scientist, Bruce Alberts, suggested using tiny beads in experiments. Dr. Tickle and her team soaked these beads in extracts from the ZPA. They placed these beads on developing chicken limbs. They also tested other chemicals.

In the early 1980s, Dr. Tickle's lab made an important discovery. They found that retinoic acid could act like the ZPA. When beads soaked in retinoic acid were placed on a limb, they could cause similar limb development.

Later, Dr. Tickle worked with other scientists to study genes. They found that if a limb was duplicated using retinoic acid, the pattern of certain genes (called Hox genes) would also be copied.

In 1994, Dr. Tickle worked with Gail Martin and Lee Niswander. They discovered that fibroblast growth factors (FGF) are used by the AER for signaling. They also found that bone morphogenetic proteins (BMP) are involved in the ZPA's signaling. They used the bead method again. When the AER was removed and FGF-soaked beads were put in its place, the chicken wing could still develop properly. This was a big step in understanding limb growth.

One of Dr. Tickle's students found that even a few hours of FGF signaling from a bead could start the growth of a new limb. This showed how powerful these signals are. It also meant that FGF signaling must turn off when a limb is fully formed. If it doesn't, extra digits or other problems could happen.

Awards and Recognition

Cheryll Tickle has received many important awards for her scientific work:

• She became a Fellow of the Royal Society (FRS) in 1998. This is a very high honor for scientists in the UK.
• She was also made a Fellow of the Royal Society of Edinburgh (FRSE) in 2000.
• In 2001, she became a Fellow of the Academy of Medical Sciences (FMedSci).
• She was also elected a member of the European Molecular Biology Organisation in 2001.
• The University of St. Andrews gave her an honorary doctorate in 2004.
• In 2005, she was named a Commander of The Most Excellent Order of the British Empire (CBE). This is a special award from the British monarch.

Her nomination for the Royal Society praised her work. It highlighted her discoveries about the ZPA's signal and how it affects digit patterns. It also noted her finding that retinoic acid can mimic this signal. Her work showed how these signals control gene expression. She also proved that fibroblast growth factor is essential for limb development. Her research is known for its excellent experiments and clear interpretations.

Personal Life

Cheryll Tickle married John Gray in 1979.