Jeffrey C. Hall facts for kids

Quick facts for kids Jeffrey C. Hall
Jeffrey C. Hall at Nobel Prize press conference in Stockholm, December 2017
Born	Jeffrey Connor Hall (1945-05-03) May 3, 1945 (age 80) New York City, U.S.
Education	Amherst College (BA) University of Washington, Seattle (MS, PhD)
Known for	Cloning the period gene
Awards	Genetics Society of America Medal (2003) Gruber Prize in Neuroscience (2009) Louisa Gross Horwitz Prize (2011) Gairdner Foundation International Award (2012) Shaw Prize (2013) Wiley Prize (2013) Nobel Prize in Physiology or Medicine (2017)
Scientific career
Fields	Genetics
Institutions	Brandeis University University of Maine
Thesis	Genetic analysis of two alleles of a recombination-deficient mutant in drosophila melanogaster (1971)
Doctoral advisor	Lawrence Sandler
Other academic advisors	Seymour Benzer, Herschel L. Roman

Jeffrey Connor Hall, born on May 3, 1945, is an American scientist. He studies genetics and chronobiology, which is the study of how living things keep track of time. Dr. Hall is a retired Biology Professor from Brandeis University.

Dr. Hall spent his career studying how the brains of fruit flies control their behavior. He especially looked at how they find mates and follow daily rhythms. His work with tiny fruit flies, called Drosophila melanogaster, helped us understand how our bodies' internal clocks work. He also learned about how male and female brains develop differently.

Because of his amazing discoveries about body clocks, he became a member of the National Academy of Sciences. In 2017, Dr. Hall, along with Michael W. Young and Michael Rosbash, won the Nobel Prize in Physiology or Medicine. They received the award for finding out how our bodies' internal clocks, called circadian rhythms, work at a tiny, molecular level.

About Jeffrey C. Hall

His Early Life and School

Jeffrey Hall was born in Brooklyn, New York. He grew up near Washington D.C., where his father worked as a reporter. His father encouraged him to read the daily newspaper and stay updated on events.

Hall went to Walter Johnson High School and graduated in 1963. He was a good student and first planned to become a doctor. In 1963, he started college at Amherst College. There, he discovered his love for biology.

For a special project, Hall worked with Philip Ives. Ives was a big influence on him. Hall became very interested in studying Drosophila (fruit flies) in Ives's lab. He studied how genes mix and move around in these flies. His successful research led his professors to suggest he go to graduate school. He chose the University of Washington in Seattle, which had a whole department for genetics.

Starting His Science Career

In 1967, Hall began working in Lawrence Sandler's lab during graduate school. He studied how enzymes in Drosophila change with age. He also looked at how chromosomes behave during meiosis, a type of cell division.

Another scientist, Hershel Roman, encouraged Hall to work with Seymour Benzer. Benzer was a pioneer in genetics. In 1971, after finishing his PhD, Hall joined Benzer's lab. There, he learned about the brain structure and chemistry of Drosophila.

In 1974, Hall became an Assistant Professor of Biology at Brandeis University. He was known for his unique way of teaching.

Challenges in Science

Dr. Hall faced many challenges while working on chronobiology. His new way of studying biological clocks using genetics was not easily accepted. When he tried to show the importance of a specific sequence of proteins he found, many scientists were doubtful. At that time, only Michael W. Young was working on a similar project.

Hall also found the process of getting money for research very frustrating. These challenges were a main reason he left the field later on. He felt that the rules and expectations in biology stopped scientists from doing the research they truly wanted. Hall believed that the focus should be on the individual's research. Funding, he thought, should give scientists freedom to explore new ideas. He loved his research and his flies, but felt that the rules made it hard to make new progress.

Discoveries About Fruit Flies

How Fruit Flies Find Mates

Dr. Hall's work on how Drosophila find mates started when he was a postdoctoral researcher. He worked with Doug Kankel to link courtship behaviors to the genetic sex of different brain parts in fruit flies. This work made him interested in the genetics of fruit fly courtship. It led him to study this topic for the rest of his career.

In the late 1970s, Hall worked with Florian von Schilcher. They found the brain areas in Drosophila that control the male's courtship songs. Hall realized that the courtship song was a good way to measure behavior. He decided to study it more.

Later, with Bambos Kyriacou, a researcher in his lab, Hall found something amazing. The Drosophila courtship song was produced in a rhythm, about once every minute.

The period Gene Connection

Hall and Kyriacou thought that a gene called period might affect the courtship song. This gene was known to cause unusual sleep-wake cycles. They tested how changes in the period gene affected the courtship song.

They found that the period gene mutations changed the courtship song in the same way they changed the daily rhythms.

• A specific change called per^s made the song rhythm shorter (about 40 seconds).
• Another change, per^l, made it longer (about 76 seconds).
• A change called per^o made the song have no regular rhythm at all.

The fruitless Gene

In his research, Hall also focused on flies with the fruitless gene. He started studying this gene during his postdoctoral years. Flies with a changed fruitless (fru) gene could not reproduce. They would try to court both female and male flies, but they never actually mated. This behavior was first noticed in the 1960s, but Hall's group was the first to study it deeply.

In the mid-1990s, Hall worked with Bruce Baker and Barbara Taylor. They successfully copied the fruitless gene. Through more research, Hall confirmed that fruitless is a master gene that controls courtship behavior. He found that without certain proteins from the fru gene, male flies would hardly court females. They also failed to sing the pulse song, never tried to mate, and courted other males more often.

The Body Clock and Genes

Dr. Hall mainly used Drosophila to study how circadian rhythms work. Instead of measuring when flies hatch from their pupae, he measured their movement. This helped him observe their daily rhythms.

How the PER Protein Works

In 1990, working with Michael Rosbash and Paul Hardin, Hall made a key discovery. They found that a protein called Period (PER) helps stop its own creation. Even though they didn't know everything about PER's role, they created a model. This model showed a "negative feedback loop" where PER levels control how much of the period gene is expressed.

In this model, when the period gene is active, it makes more PER protein. Once there's enough PER, it tells the period gene to slow down. This causes PER levels to drop, which then allows the period gene to become active again. This cycle is a main part of the circadian clock in Drosophila.

How Cells Stay in Sync

In 1997, Hall was part of a team that found that genes involved in the body clock are active in cells all over the body. Even though these genes are needed for the clock, their activity levels varied in different body parts and even in different cells. Hall was able to train separate tissues to different light-dark cycles at the same time.

Hall didn't discover what makes cells work together until 2003. He found that a protein called pigment dispersing factor (PDF) helps control the daily rhythms and movement of these genes in cells. This protein was found in specific neurons in the Drosophila brain. From this, Hall concluded that these neurons act as the main "pacemaker" for the flies. PDF helps all the cells stay in sync. His work on this led to him receiving the 2017 Nobel Prize.

Improving the Body Clock Model

In 1998, Hall helped make two more discoveries that improved the body clock model. The first was about how Cryptochrome (CRY) helps set the clock. Hall found that CRY is a key light sensor. It helps the clock adjust to light and dark, and also controls movement. He thought CRY might not just be an input, but also part of the clock itself.

In the same year, Hall discovered how the Drosophila period and timeless (tim) genes are controlled. He found that two proteins, CLOCK and Cycle (CYC), join together. Once joined, they attach to a specific part of the period and timeless genes. This attachment tells the genes to start making their mRNA, which leads to the creation of the PER and TIM proteins.

See also

In Spanish: Jeffrey C. Hall para niños