He was first to discover that red blood cell production is controlled by hematopoietin (or erythropoietin), a regulatory hormone that induces production in response to an organism's physiologic need.
An innovator who designed the first semi-automatic micromanipulator driven by servo-motors and simple computer circuits as well as device for repetitive microinjection of sub nanoliter volumes.
An authority on heterochromatin, and chromatin state and modification that is now acknowledged as a second code of DNA called the histone code. His early work on heterochromatin state was foundational in this area.
A world-renowned soil biochemist and microbial ecologist and AAAS Fellow. One of his major projects involved pioneering work on the persistence and ecological effects of transgenic plants and the insecticidal toxins from Bacillus thuringiensis in soil.