What is sufficient to show possession of an invention in biology and chemistry

Inventorship in an unpredictable field is a challenge to all involved. It may require demonstration of the invention itself, rather than disclosure of a method that might work to generate that invention. In the US, unlike authorship of a scientific article, it can make or break a company. Thus, not only can egos be affected, but so can an industry. The authors discuss some of the more complex issues and problems involved and suggest practical solutions.