Donald David Brown (December 30, 1931 – May 31, 2023) was an American biologist and one of the founders of molecular embryology.

Early life

Brown was born in

Cincinnati Cincinnati ( ) is a city in the U.S. state of Ohio and the county seat of Hamilton County. Settled in 1788, the city is located at the northern side of the confluence of the Licking and Ohio rivers, the latter of which marks the state line wit ...

Ohio Ohio () is a state in the Midwestern region of the United States. Of the fifty U.S. states, it is the 34th-largest by area, and with a population of nearly 11.8 million, is the seventh-most populous and tenth-most densely populated. The sta ...

to Dr. Albert Brown, an

ophthalmologist Ophthalmology ( ) is a surgery, surgical subspecialty within medicine that deals with the diagnosis and treatment of eye disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Followin ...

, and Louise Rauh.

Education

Brown attended

Dartmouth University Dartmouth University is a defunct institution in New Hampshire which existed from 1817 to 1819. It was the result of a thwarted attempt by the state legislature to make Dartmouth College, a private college, into a public university. The United ...

. In 1956, he received an MD and MS from

University of Chicago Medical School The Pritzker School of Medicine is the M.D.-granting unit of the Biological Sciences Division of the University of Chicago. It is located on the university's main campus in the historic Hyde Park neighborhood of Chicago and matriculated its f ...

, writing his master's thesis on the mechanism of viral invasion.

Career

After a year working as an intern at

Charity Hospital Charity may refer to: Giving * Charitable organization or charity, a non-profit organization whose primary objectives are philanthropy and social well-being of persons * Charity (practice), the practice of being benevolent, giving and sharing * Ch ...

in New Orleans, Brown began a two year fellowship with the

National Institutes of Health The National Institutes of Health, commonly referred to as NIH (with each letter pronounced individually), is the primary agency of the United States government responsible for biomedical and public health research. It was founded in the late ...

the direction of neuroscientist

Seymour Kety Seymour S. Kety (August 25, 1915 – May 25, 2000) was an American neuroscientist who was credited with making modern psychiatry a rigorous and heuristic branch of medicine by applying basic science to the study of human behavior in health and ...

. In 1959, he conducted postdoctoral studies with

Jacques Monod Jacques Lucien Monod (February 9, 1910 – May 31, 1976) was a French biochemist who won the Nobel Prize in Physiology or Medicine in 1965, sharing it with François Jacob and André Lwoff "for their discoveries concerning genetic control of en ...

at the

Pasteur Institute The Pasteur Institute (french: Institut Pasteur) is a French non-profit private foundation dedicated to the study of biology, micro-organisms, diseases, and vaccines. It is named after Louis Pasteur, who invented pasteurization and vaccines f ...

Paris, France Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), ma ...

. Brown joined the

Carnegie Institution The Carnegie Institution of Washington (the organization's legal name), known also for public purposes as the Carnegie Institution for Science (CIS), is an organization in the United States established to fund and perform scientific research. Th ...

Baltimore, Maryland Baltimore ( , locally: or ) is the List of municipalities in Maryland, most populous city in the U.S. state of Maryland, fourth most populous city in the Mid-Atlantic (United States), Mid-Atlantic, and List of United States cities by popula ...

in 1961. He initially joined the Department of Embryology as a staff scientist. In 1976, he became director of the department. Beginning in 1969, he was an adjunct professor of biology at

Johns Hopkins Johns Hopkins (May 19, 1795 – December 24, 1873) was an American merchant, investor, and philanthropist. Born on a plantation, he left his home to start a career at the age of 17, and settled in Baltimore, Maryland where he remained for most ...

. He was a member of the

American Academy of Arts and Sciences The American Academy of Arts and Sciences (abbreviation: AAA&S) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and ...

, the

National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...

, and the

American Philosophical Society The American Philosophical Society (APS), founded in 1743 in Philadelphia, is a scholarly organization that promotes knowledge in the sciences and humanities through research, professional meetings, publications, library resources, and communit ...

. Brown retired from the

with

emeritus ''Emeritus'' (; female: ''emerita'') is an adjective used to designate a retired chair, professor, pastor, bishop, pope, director, president, prime minister, rabbi, emperor, or other person who has been "permitted to retain as an honorary title ...

status in 2005.

Discoveries

Brown and

John Gurdon Sir John Bertrand Gurdon (born 2 October 1933) is a British developmental biologist. He is best known for his pioneering research in nuclear transplantation and cloning. He was awarded the Lasker Award in 2009. In 2012, he and Shinya Yamanaka ...

found that certain

frog A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...

mutants lacked

nucleoli The nucleolus (, plural: nucleoli ) is the largest structure in the nucleus of eukaryotic cells. It is best known as the site of ribosome biogenesis, which is the synthesis of ribosomes. The nucleolus also participates in the formation of sig ...

and thus did not produce ribosomal RNAs (rRNAs), indicating that nucleoli were the site of rRNA production. Later, Brown and Igor Dawid investigated why frog

oocytes An oocyte (, ), oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female ge ...

contained many more nucleoli than did

somatic cells A somatic cell (from Ancient Greek σῶμα ''sôma'', meaning "body"), or vegetal cell, is any biological cell forming the body of a multicellular organism other than a gamete, germ cell, gametocyte or undifferentiated stem cell. Such cells compo ...

. They showed that the number of rDNA genes was amplified during

oogenesis Oogenesis, ovogenesis, or oögenesis is the differentiation of the ovum (egg cell) into a cell competent to further develop when fertilized. It is developed from the primary oocyte by maturation. Oogenesis is initiated in the embryonic stage. O ...

to support

ribosome Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to ...

production needed for each oocyte (this discovery was independently made by Joseph Gall). After

Max Birnstiel Max Luciano Birnstiel (12 July 1933 – 15 November 2014) was a Swiss molecular biologist who held a number of positions in scientific leadership in Europe, including the chair of the Institute of Molecular Biology at the University of Zurich from ...

managed to isolate rDNA genes, Brown was the first who purified the genes encoding the smaller

5S rRNA The 5S ribosomal RNA (5S rRNA) is an approximately 120 nucleotide-long ribosomal RNA molecule with a mass of 40 kDa. It is a structural and functional component of the large subunit of the ribosome in all domains of life (bacteria, archaea, and e ...

genes and found a way to transcribe them in vitro. In fact, 5S rRNA genes were the first eukaryotic genes to be cloned. Brown and Robert Roeder found later that

transcription Transcription refers to the process of converting sounds (voice, music etc.) into letters or musical notes, or producing a copy of something in another medium, including: Genetics * Transcription (biology), the copying of DNA into RNA, the fir ...

of these genes was regulated by a transcription factor (TFIIIA) that binds within the gene.

References

1931 births 2023 deaths American embryologists Pritzker School of Medicine alumni Johns Hopkins University faculty Members of the American Philosophical Society Members of the United States National Academy of Sciences Fellows of the American Academy of Arts and Sciences Fellows of the American Association for the Advancement of Science {{US-scientist-stub