This paper aims to highlight the basis of the space syntax approach, specifically the justified
graph method or "gamma-analysis" in the identification of domestic architectural types
according to their spatial organizations and their dwelling patterns. This identification is done
through a concept borrowed from genetics and transmitted to architecture: The genotype and
phenotype. Based on several examples, this article will explain the way in which the hidden
socio-spatial structures of buildings will be highlighted. Originally used in Anglo-Saxon
countries, this approach is currently used by a large number of researches focused on
architectural spatiality especially domestic at the global level. The article will end with the
critique of the method in terms of usefulness and significance of its results.