Genotype networks are a concept used in the field of systems biology to study the ''evolvability'' or ''innovability'' of a set of genotypes having the same, broadly defined, phenotype, such as viability, and to determine whether a given phenotype is robust to mutations. They have been used to study the evolvability of metabolic networks in simple organisms, by identifying how much a metabolic network can be altered without losing the ability of surviving using a given carbon source. Similarly, they have been used to study the ability of a metabolic network to ''evolve'' a new phenotype, such as the ability of surviving on a new carbon source

In two different publications researchers describe the concept, application and the bioinformatic tools to be able to work with them:

Reference article: Dall'Olio, G.M., Bertranpetit, J., Wagner, A.,  Laayouni H. 2014. Human Population Genetics and the concept of Genotype Space.  Plos One, 2014; 9(6):e99424.

Reference Article: Dall'Olio G.M., Vahdati A.R.,  Bertranpetit J., Wagner A., Laayouni H. VCF2Networks: applying Genotype Networks to Single Nucleotide Variants data. Bioinformatics. 2014, Oct 4. pii: btu650. PMID: 25282646