In genetics, the<unk> , also known as ω or dN/dS ratio, is used to estimate the balance between neutral mutations, purifying selection and beneficial mutations acting on a set of homologous protein-coding genes. It is calculated as the ratio of the number of nonsynonymous substitutions per non-synonymous site <unk> , in a given period of time, to the number of synonymous substitutions per synonymous site <unk> , in the same period. The latter are assumed to be neutral, so that the ratio indicates the net balance between deleterious and beneficial mutations. Values of<unk> /Ks significantly above 1 are unlikely to occur without at least some of the mutations being advantageous. If beneficial mutations are assumed to make little contribution, then<unk>  estimates the degree of evolutionary constraint.
Ka/Ks ratio
E/A ratio
NC ratio
Rate pressure product
Extraction ratio
QT interval
QRS complex
PR interval