Gene
A gene represents a small amount of the information which, together with other genes like it, comprises the genome of an individual. Except in special circumstances, the gene can be thought of as the smallest unit on which natural selection acts. We know this, because we either inherit a gene from our parents or we don't: conversely, we either pass a particular gene to our offspring, or we don't, and natural selection favors genes that aid in the survival and reproduction of the bodies they inhabit.
The genes in the cells of real living creatures each code an amount of information which is impressive by biological standards, but long well within the reach of modern computer memories. The human genome contains approximately 3 billion base pairs. Since each base pair encodes the equivalent of two binary bits of information, there are 6 billion bits in the human genome, or 1.5 billion bytes.
The individual genes which comprise this total are smaller. There are some estimated 20,000 genes in the human genome, so, taking a crude fraction, an individual gene might comprise some tens of kilobytes.
In Blind Watchmaker, genes are represented as numeric values, and values chosen from specialized lists of possible values of a given gene type, such as 'left'- and 'right'-handedness for conchomorphs. Though the information content of a typical biomorph gene is much smaller than that of the genes in living cells, the number of possible values for a biomorph gene is still staggering.