The details of norns, grendels, ettins and geats in games in the Creatures series - such as their brains, biochemistry and appearance - are to a great degree dictated by virtual genetics using a simulated genome; often called Digital DNA.
Things which are defined in genomes include:
- brain information (lobes, and the dendrites and neurons they contain)
- chemical reactions and half-lives (norns can become immortal and such things when these mutate)
- concentrations of chemicals in the bloodstream at birth
- biochemistry workings (receptors, emitters, and 'neuro emitters' which link with the brain systems)
- creature appearance; pose, pigments and gait, among other things
As of Creatures 2, creatures had around 800 genes, half of which were used for behavioural patterns and physical appearance, while the other half determined the biochemistry and the nervous system.