This document provides an annotated timeline of key events in the development of U.S. patent law as it relates to genetics from 1474 to 2000. Some of the major events included are the first patent statute passed by the U.S. Congress in 1790, Louis Pasteur being awarded the first patent on a microorganism in 1873, the Supreme Court ruling in 1980 that living matter can be patented as long as it results from human manipulation, and patents being awarded in the U.S. and Britain in the late 20th century for cloned non-human animals and human cell lines. The timeline traces the evolving interpretation and application of patent law to new biotechnologies over centuries.