As a special scenario of insertions, gene duplication consists of a full copy of a randomly selected row/column pair inserted into the individual's network resulting in an individual with an extra copy of a gene. Gene duplication generates viable individuals around 50% of the time independent of the number of genes in the network. This independence of the number of genes in the network is a unique feature of gene duplication that allows creation of complex viable networks.
Carneiro et al. BMC Evolutionary Biology 2011 11:363 doi:10.1186/1471-2148-11-363