Amita Sehgal facts for kids

Amita Sehgal is a brilliant scientist who studies how our bodies tell time. She is a molecular biologist and chronobiologist at the Perelman School of Medicine at the University of Pennsylvania. Dr. Sehgal helped discover important parts of the "body clock" in fruit flies, especially a gene called timeless.

She also played a big role in using fruit flies to study sleep. Her research today focuses on understanding why we sleep and how our body clocks affect other parts of our health.

Dr. Sehgal's Journey in Science

Dr. Sehgal grew up in India. She earned her first science degrees from Delhi University and Jawaharlal Nehru University in New Delhi. In 1983, she started her PhD at Cornell University in the United States. This is where her passion for science really grew!

In 1988, she began working at Rockefeller University with scientist Michael Young. There, she started studying circadian rhythms, which are like our body's natural 24-hour clocks. She has been studying them ever since!

Amazing Discoveries in Research

Key Moments in Her Research

• 1994: She found a special change in the timeless gene in fruit flies.
• 1995: She identified the timeless gene and showed it changes daily.
• 1996: She proved that light can reset the timeless gene.
• 2000: She helped create a way to study sleep using Drosophila (fruit flies).
• 2001: She showed that a gene called neurofibromin 1 is part of the body clock in fruit flies.
• 2006: She discovered the jetlag gene, which helps reset the body clock.
• 2006: She found that a part of the fruit fly brain, called mushroom bodies, is important for sleep.
• 2008: She discovered the sleepless gene in fruit flies.
• 2014: She mapped brain pathways that connect the body clock to behavior.
• 2014: She found out why young animals sleep so much.
• 2018: She found a possible reason why adult flies need sleep.
• 2018: She showed that the blood-brain barrier changes with the body clock.
• 2019: She found a link between sleep and the body's defense system.

The Timeless and Period Genes

Dr. Amita Sehgal has greatly helped us understand the biological clock of Drosophila melanogaster (fruit flies). In 1994, she and her team found a changed version of the timeless (TIM) gene in fruit flies.

The next year, Dr. Sehgal and her colleagues found the actual TIM gene. They showed that TIM and another gene called PER have similar daily cycles. They suggested that PER and TIM work together and build up during the day. In the evening, they go into the cell's control center (the nucleus) to stop making more of their own instructions. In 1996, Dr. Sehgal's lab showed that when light causes TIM levels to drop, it resets the body clock.

Neurofibromin 1 and Body Clocks

Neurofibromin 1 (NF1) is a gene that helps prevent tumors. In 2001, Dr. Sehgal and her team learned that some people with a condition called Neurofibromatosis type 1 (which affects NF1) also have trouble sleeping.

So, they studied fruit flies with a broken NF1 gene. They found that these flies also had messed-up body clocks. When they put a working NF1 gene back into the flies, their body clocks became normal again. This showed that NF1 is involved in how the body clock works.

Understanding Jetlag

In 2006, Dr. Sehgal and her team found a fruit fly that took a very long time to get used to new light and dark schedules. They named the changed gene jetlag (jet). This gene makes a protein called JET. JET helps reset the fruit fly's clock.

JET helps break down the TIMELESS (TIM) protein when there is light. This breakdown is important for the clock to adjust to outside light signals.

Mushroom Bodies and Sleep

Mushroom bodies are parts of the Drosophila brain. They are known to help with learning, memory, smell, and movement. In 2006, Dr. Sehgal and her team discovered that mushroom bodies also play a big role in controlling sleep in flies.

They found that this brain part is very important for fly sleep. While we don't yet know the exact way mushroom bodies control sleep, they might help flies fall asleep by stopping them from processing too much sensory information.

The Sleepless Gene

In 2008, Dr. Sehgal and her team discovered the sleepless gene in fruit flies. When this gene was changed, the flies slept 80% less than normal flies. They also lived only half as long!

Dr. Sehgal's team found that the SLEEPLESS protein helps control certain channels in cells that affect how nerves work.

Why We Sleep

All animals, including humans, sleep a lot when they are young. Dr. Sehgal and her team found out what keeps sleep levels high in young fruit flies. They also discovered that if young flies don't get enough sleep, their mating behavior as adults is affected. This suggests that sleep might be needed for the brain to develop properly for important behaviors.

For adult animals, one possible reason for sleep is to help clear out waste. Dr. Sehgal's team found that sleep helps cells take in things through the blood-brain barrier in flies.

Body Clocks, Behavior, and the Blood-Brain Barrier

The blood-brain barrier (BBB) is like a shield that protects the brain from harmful things. But it can also make it hard for medicines to reach the brain. Dr. Sehgal and her team found that the fly's BBB changes how "leaky" it is throughout the day and night. This means some medicines might work better at certain times of the day. They have also mapped out the brain pathways that connect the body clock to how animals behave.

Sleep and Your Immune System

Scientists wanted to find molecules that make you sleep. Dr. Toda and her team looked at over 10,000 types of fruit flies and found one that caused sleep. They named this molecule nemuri. It is a special protein that fights germs. When flies get an infection or don't get enough sleep, this protein is made. It helps them survive by killing bacteria and making them sleep more.

Awards and Important Roles

Important Roles

• Director, Chronobiology and Sleep Institute (CSI), University of Pennsylvania, since 2019
• Director of Penn Chronobiology Program, 2014-2019
• Howard Hughes Medical Institute Investigator, since 1997
• John Herr Musser Professor of Neuroscience, University of Pennsylvania
• Vice Chair of the Department of Neuroscience
• Co-Director of the Penn Medicine Neuroscience Center, 2008-2014

Awards and Honors

• Outstanding Scientific Achievement Award, Sleep Research Society
• Michael S. Brown Junior Faculty Research Award
• Stanley Cohen Senior Faculty Research Award
• Elected to the National Academy of Medicine (a very important group of scientists), 2009
• Elected to the American Academy of Arts and Sciences, 2011
• Elected Fellow of the American Association for the Advancement of Science, 2016
• Elected to the National Academy of Sciences, 2016
• Switzer Prize from UCLA, 2020