Table 1 Description of three commonly used measures of genetic difference between individuals. Each diploid individual is characterized by two individual genes at each gene locus, which are either identical in their gene state (= homozygous; e. g. A₁A₁) or different in their gene state (= heterozygous; e. g. A₁ A₂). Measurements of genetic difference between two individuals can therefore be based on either differences in number of gene states (d _J ) or on number of individual genes differing in gene state (d₀, d _ur ) at a specified number of gene loci.

$d_0=\frac{{\displaystyle {\sum }_{k}max}\left\{G_{10.k},G_{01.k}\right\}}{2\cdot l}$

the minimum number of individual genes, the states of which have to be replaced in one individual in order to get the genotype of the other individual

$d_J=\frac{{\displaystyle {\sum }_k\left(G_{10.k},G_{01.k}\right)}}{{\displaystyle {\sum }_k\left(G_{11.k}+G_{10.k}+G_{01.k}\right)}}$

the number of gene states present in only one of the two individuals among the total number of gene states present in both individuals

$d_{ur}=\frac{{\displaystyle {\sum }_k{G}_k}}{4\cdot l}$

the expected relative degree of heterozygosity of the off- spring of two individuals