Donald Brown received his M.D. and M.S. in biochemistry from the University of Chicago Medical School in 1956. It was there that he began to wonder how embryos develop. At the time, scientists had mapped out the process that produced anatomical features but not the molecular underpinnings. Brown launched a bold, independent research program to study the details by looking at embryos that die particularly early—when new ribosomes start accumulating. In collaboration with John Gurdon, Brown discerned that the nucleolus manufactures structural RNAs of the ribosome (ribosomal RNAs, or rRNAs).

Frog embryos do not make ribosomes during the first few days of development. Instead, they use the stockpile that the egg endowed to them. No one knew how a single cell could churn out so many protein-making factories. Brown and Igor Dawid (and, independently, Carnegie’s Joseph Gall) showed that frog eggs create extra rRNA genes. The researchers revealed the first example of gene amplification, which underlies other processes, including the runaway growth of drug-resistant cancer cells.

Brown used the amplified genes to isolate and study rRNA genes, which later resulted in studying genes via recombinant DNA. This laboratory method brings genetic material from various sources to produce sequences not found in nature. Brown used recombinant DNA to analyze an RNA called 5S RNA, and he found a region in the middle of the gene that unexpectedly governs production of the gene’s RNA—the first known “internal control region.”

Over the years, Brown has made numerous fundamental discoveries concerning the nature of genes. He has also maintained a selfless commitment to young scientists by mentoring a generation of scientists at Carnegie and by founding and leading the Life Sciences Research Foundation (LSRF), a partnership that provides postdoctoral fellowships to some of the world’s most promising researchers.
Brown joined Carnegie Embryology in 1961 as a fellow. He later became a staff member, and then he became director of the department in 1976, where he built a world-renowned department. When Brown left the directorship in 1994 to become a staff member again, five of the eight laboratory heads were members of the U.S. National Academy of Sciences (NAS). 

Watch: Donald Brown - 90th Birthday Symposium (2022).

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