Joseph Grafton Gall (April 14, 1928 – September 12, 2024) was an American cell biologist who studied the structure and function of chromosomes. His research was helped by his understanding of many different organisms, which allowed him to choose the best organism to study when investigating questions about nuclear structure. He received the 2006 Albert Lasker Special Achievement Award. He also shared the 2007 Louisa Gross Horwitz Prize from Columbia University with Elizabeth Blackburn and Carol W. Greider. In 1983, he was given the highest honor by the American Society for Cell Biology, the E. B. Wilson Medal. He was elected to the American Academy of Arts and Sciences in 1968, the National Academy of Sciences in 1972, and the American Philosophical Society in 1989.
Research career
Gall was called "the father of cell biology" when he received the Lasker Award. He helped develop the idea that a chromosome contains one DNA molecule that runs from one end to the other. After DNA replication, each of the two daughter chromatids had one DNA molecule running its full length. Gall studied this structure by looking at amphibian lampbrush chromosomes under a microscope. He used special stains to highlight DNA and RNA and treated the chromosomes with enzymes that break down DNA or RNA. The Feulgen stain for DNA was not sensitive enough to color the loops of these chromosomes but only stained the long axis. However, the loops were affected by DNase, which showed they contained DNA that kept their loop shape. Later, using DAPI, a more sensitive dye, Gall saw DNA running through each loop and returning to the chromosome's axis. He also discovered the structure and location of rDNA, the part of the genome that makes ribosomal RNA, and made many other important findings about nuclear structure.
Gall and his graduate student, Mary-Lou Pardue, wanted to find where a special repeated DNA sequence called satellite DNA was located in chromosomes. To locate this DNA, they created a widely used laboratory method called in situ hybridization. Using this technique, they found satellite DNA at the ends of chromosomes, called telomeres.
When Elizabeth Blackburn, a 2009 Nobel Prize winner in Medicine, worked with Gall, they studied the ends of chromosomes and identified the main short repeated sequence found in telomeres of most complex organisms. Later, Blackburn and her student Carol Greider discovered the enzyme telomerase, which helps maintain the length of telomeres, and explained its role in aging.
Role as a mentor of women scientists
Joseph Gall is known for supporting women in the field of biology, a group sometimes referred to as "Gall's Gals," during a time when this was not common. Many of his former students have been chosen to join the National Academy of Sciences and have received important awards, including the Nobel Prize. Some of his students include Joan Argetsinger Steitz, Mary-Lou Pardue, and Elizabeth Blackburn.
One of Gall's students who made significant contributions to the study of cells is Susan Gerbi. She co-wrote an article about Gall's life and work in 2003. In interviews with Gall, when asked about his support for women in science, he mentioned his mother. She was skilled in math and science and was the first woman in her family to attend college, graduating in the 1920s. After college, she became a homemaker instead of a scientist. However, she encouraged young Joseph Gall to explore the natural world by catching insects and identifying them together using scientific books. Gall said, "It never occurred to me that a woman's ability was different than a man's." He also noted that his father, a lawyer, was afraid of animals and insects, adding, "If anything, maybe I thought it went the other way."
Death and legacy
In 2005, Gall appeared in interviews with famous TV host Bill Nye for the Science Channel's 100 Greatest Discoveries series. Gall passed away at his home in Baltimore on September 12, 2024, at the age of 96.