Martha Chase, who was half of a scientific team that in 1952 used a kitchen blender to help prove that DNA is the molecule that carries genetic information, died on Aug. 8 in Lorain, Ohio, a suburb of Cleveland. She was 75.
The cause was pneumonia, said her sister, Ruth Daziel of Milford, Conn.
Ms. Chase had just graduated from the College of Wooster in Ohio when she was hired as a research assistant by Dr. Alfred D. Hershey, a biologist who was investigating how viruses replicate. Working at the Cold Spring Harbor Laboratory on Long Island, the two devised an experiment to determine whether DNA or its associated protein carried the genetic information for infection, growth and development.
The experiment was simple and elegant. Using radioactive tracers to mark the DNA core and the protein coat of a phage, or bacterial virus, the two researchers placed the material in a blender and turned on the switch. After the blender had separated the DNA and the protein, an examination showed that only the DNA had entered the bacteria at the time of infection; this DNA then led to the replication of the virus.
The experiment had implications far beyond the study of viruses. It provided one of the foundations of molecular biology and helped inspire Dr. James D. Watson and Dr. Francis Crick in their development 11 months later of the helix model of DNA. Dr. Hershey received the Nobel Prize in 1969 for his insights into the nature of viruses.
Ms. Chase left Cold Spring Harbor in 1953 to work at the Oak Ridge National Laboratory in Tennessee and later at the University of Rochester. She returned to Cold Spring Harbor each summer during the 1950's to participate in the meetings of the influential Phage Group of biologists. In 1959, she began work on her doctorate at the University of Southern California. After receiving it in 1964, she returned to Cleveland.
Martha Chase was born on Nov. 30, 1927. Married briefly in the late 1950's, she is survived by her sister.
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