Hamilton O. Smith

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New York City, New York
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Hamilton Othanel Smith is an American microbiologist who won the 1978 Nobel Prize in Physiology or Medicine. He shared the prize with two other microbiologists for discovering’restriction enzymes’ that could break down the DNA in a cell into smaller pieces for easier study. Werner Arber of Switzerland and Daniel Nathans of America were the other two microbiologists who shared the prize. Smith discovered a new class of enzymes called’restriction enzymes’ that could recognize a specific sequence of nucleotides in a DNA or ‘deoxyribonucleic acid’ molecule and cut it at that point. This discovery laid the groundwork for the future use of’restriction enzymes’ in genetics and microbiology to study the DNA of various biological systems. Arber and other microbiologists had previously discovered that one type of’restriction enzyme’ recognizes DNA sequences and cuts them up randomly but not at the recognition site. Smith and his colleagues discovered the second type of’restriction enzymes’ while studying the bacteria ‘Haemophilus influenzae,’ which not only recognizes but also cuts the DNA molecule precisely at that point.

Childhood & Adolescence

Daniel O. Smith was born in New York City on August 23, 1931. Bunnie Othanel Smith, his father, was an Assistant Professor of Education at the ‘University of Florida’ in Gainesville, and Tommie Naomi Harkey, his mother, was a teacher.
Norman is his elder brother.

Both of his parents came from humble origins. When Hamilton was born, his father had left the university and enrolled in ‘Columbia University’ in New York City to pursue doctoral studies.

His family relocated to Champaign-Urbana, Illinois, when his father accepted a position at the ‘University of Illinois’ in the ‘Department of Education.

Smith spent his entire boyhood in Champagne-Urbana, a town that remained relatively unaffected by global events such as the Great Depression and World War II.

He attended Urbana, Illinois’s ‘University Laboratory High School,’ where the majority of students were exceptionally gifted and descended from university faculty families.

He graduated from high school in three years with the assistance of Wilbur E. Hamish, who taught him chemistry and physics, Vynce Hines, who taught him plane geometry, and Miles C. Hartley, who taught him algebra.

After high school, he enrolled at the ‘University of Illinois’ with mathematics as a major but was undecided about his future studies. He became interested in the central nervous system after his brother introduced him to a book about its mathematical modeling written by a biophysicist, Rashevsky.

He began his academic career in 1950 at the ‘University of California’ at Berkeley, where he developed an interest in biochemistry, biology, and cell physiology.

Smith graduated in 1952 from the University of California, Berkeley with a bachelor’s degree in mathematics.

Smith chose a medical career and enrolled in the ‘John Hopkins University Medical School’ in Baltimore, Maryland in 1952.

In 1956, he earned his M.D. from ‘John Hopkins University’ and completed his medical internship at ‘Barnes Hospital’ in St. Louis.

Career of Hamilton O. Smith

Hamilton O. Smith enlisted in the Navy in July 1957 after being drafted into the Armed Forces and served for two years in San Diego, California. During this time period, he developed an interest in genetics.

In 1959, he moved to Detroit, Michigan, with his wife and one-year-old son, to complete his medical residency training at the ‘Henry Ford Hospital.’ He discovered his calling here after coming across books by Mark Adams and others on ‘bacteriophage’ and molecular biology.

After completing a postdoctoral fellowship at the National Institutes of Health, he joined the ‘Department of Human Genetics’ at the ‘University of Michigan’ in Ann Arbor in 1962. He began collaboration with another geneticist, Mike, on the ‘Salmonella Phage P22 lysogeny.’

They discovered the gene that regulated prophage attachment in 1965, and Smith was able to publish his findings in 1967.

He returned to ‘John Hopkins’ in 1967 as an Assistant Professor of Microbiology and has remained there ever since.

In 1968, he discovered the first type-II’restriction enzyme’ capable of fragmenting the DNA molecule at specific points.

In 1973, he was appointed full professor of microbiology in the department of microbiology.

Between 1975 and 1976, he was awarded a ‘Guggenheim Fellowship’ and collaborated on the sequencing and arrangement of the ‘histone gene’ with Max Birnstiel at the ‘University of Zurich’ in Switzerland.

Smith was successful in 1995 at ‘The Institute for Genomics Research’ or ‘TIGR’ in sequencing the genome of the ‘Haemophilus influenzae’ bacteria with the assistance of other researchers.

In 1998, he left ‘John Hopkins’ and joined ‘Celara Genomics Corporation,’ a company that conducted research with private funding. He aided in the efforts there to sequence the genomes of ‘fruit flies’ or ‘Drosophila’ and humans.

In 2002, he was appointed scientific director of the ‘Institute for Biological Energy Alternatives,’ or ‘IBEA,’ in Maryland. His basic research at this institute focused on the development of a synthetic organism composed of a single cell capable of self-replication and survival. The primary objective of this research was to determine the bare minimum number of genes required to sustain life.

Smith was appointed head of the ‘J. Craig Venter Institute’s’ synthetic biology and biological energy research group in 2006, following the merger of TIGR and IBEA.

He is currently the scientific director of privately held ‘Synthetic Genomics,’ where he is conducting research on biofuels.

Significant Work of Hamilton O. Smith

Hamilton Smith collaborated with Kent W. Wilcox to publish his first book, ‘A restriction enzyme from Hemophilus Influenza. 1. Purification and general projects,’ in 1970.

In 1970, he co-authored ‘A restriction enzyme from Hemophilus influenza. 11. Base sequence of the recognition site’ with T. J. Kelly.

In 1973, he published his third and fourth books, ‘The DNA methylases of Hemophilus influenzae Rd. 1. Purification and properties’ and ‘The DNA methylases of Hemophilus influenzae Rd. 11. Partial recognition site base sequences’, in collaboration with P. H. Roy.

Awards and Accomplishments

In 1978, Hamilton Smith was awarded the Nobel Prize in Physiology or Medicine.

Personal History and Legacies

Hamilton O. Smith married Elizabeth Anne Bolton, a nursing student from Mexico City, in 1956, after enrolling at Johns Hopkins University’s medical school and meeting her.

He and his wife have four sons and a daughter.

Estimated Net Worth

The estimated net worth of Hamilton O. Smith is unknown.


Hamilton Smith spends his free time playing the piano and listening to classical music.