The case for serendipity  pg. 3

Salk tests injections of inactivated polio virus on himself and his family. Within two years of its widespread introduction in 1954, Salk’s vaccine nearly eliminates polio in the United States, but a live oral vaccine developed by another American physician, Albert Sabin, later becomes the preferred alternative.

Reverse transcriptase, 1970.

Working independently, David Baltimore of MIT and Howard Temin of the University of Wisconsin-Madison discover an enzyme used by certain tumor viruses to “transform” the cells they infect into cancer cells.

The enzyme, called reverse transcriptase, allows these viruses to convert their RNA into DNA copies that can slip into – and alter -- the cell’s genetic instructions. This finding leads, in 1984, to the discovery of the human immunodeficiency virus (HIV).

In recognition of their discovery, Baltimore and Temin share the 1975 Nobel Prize in medicine with Renato Dulbecco.

Gene splicing and sequencing, 1970.

John Hopkins University microbiologist Hamilton Smith sparks a revolution in genetic research when he discovers the first restriction enzyme that cuts DNA. After this comes a flurry of follow-up discoveries: the first recombinant DNA molecule in 1972; DNA cloning in 1973; rapid DNA sequencing in 1977; DNA copying in 1983; and the first automated gene sequencing machine in 1986.

Neurons derived from human embryonic stem cells project from a neurosphere in this confocal microscopy image taken by Sharona Even-Ram, Ph.D., of Hadassah University Hospital’s Goldyne Savad Institute of Gene Therapy in Jerusalem.
Understanding DNA has paved the way to gene therapy, DNA fingerprinting, a cloned sheep named Dolly, genetically engineered crops, and efforts to sequence the human genome -- a feat accomplished in 2000 by Celera Genomics and the federally funded Human Genome Project.

Embryonic stem cells, 1981.

Researchers in Britain and the United States, working independently, isolate cell lines from mouse blastocysts that are pluripotent. These so-called embryonic stem cells can be grown into all types of cells in tissue culture.

In 1988, James Thomson and coworkers at the University of Wisconsin-Madison extract the first human embryonic stem cell line -- and in 2007, the same team, simultaneously with an independent team in Japan, reports that they have successfully restored pluripotency in human connective tissues cells.

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