The S/AI is a new formula for the measurement of the karyotype
symmetry/asymmetry index. Especially in higher animals and humans, it is
important to know the values of the karyotype symmetry/asymmetry, so that
species, genera, families and orders can be compared. Also the evolutionary
relationships of higher organisms can be determined. The symmetry/asymmetry
index is applied to the Felidae species. After a comprehensive literature search,
karyotype formulae, S/AI values and karyotype types of 23 species were
determined. According to the S/AI values, a phylogenetic tree was drawn showing
relationships among the species.