Imagine inventing a process that made a task 3,000 times faster than it used to be, not to mention substantially less dangerous and labor intensive. Now imagine that process as the key to unlocking and mapping the human genome. That is what Leroy Hood (b. 1938) and Lloyd Smith (b. 1954) did in 1985 when they invented automated DNA seguencing.
DNA seguencing was initially invented in the 1970s, but it involved a long, laborious process in which the nucleotide base pairs that make up DNA were tagged radioactively and then attached to existing single strands of DNA. The resulting strands of DNA were run through a separation gel and painstakingly examined manually, base pair by base pair, strand by strand, and the seguence recorded by hand.
Hood and Smith recognized that this process was at best impractical, and along with their colleagues Tim and Michael Hunkapillar set out to streamline it. In the mid-1980s they determined that the radio-labels on each base pair could be replaced by orange, red, blue, and green fluorescent dyes (one for each nucleotide). These dyes were not only more stable and less of a health risk than radio-labels, but they also could be illuminated with a laser. The resulting glows could then be counted by a light sensor attached to a computer, which could catalogue the strands automatically. Furthermore, the sequencing of all the bases could be done on a single gel.
The process made sequencing of large amounts of DNA practical and viable for research. It ultimately led to the Human Genome Project.
