Stories by Russell F. Doolittle

Many proteins consist of a fairly small set of modular elements. How these units spread and multiplied during evolution is not altogether clear, but a pattern may be emerging

Proteins are the molecules encoded by genes. The proteins in turn give rise to structure and, by virtue of their selective binding to other molecules, make genes and all the other machinery of life

The plasma protein fibrinogen is converted into fibrin to form a blood clot. In time the clot breaks down. Both processes can now be understood in terms of the detailed structure of the protein