Table 1. The effective number of variants, k_eff|2, at a rare variant position in two related individuals that each carry a variant, as defined in Equation 1.

		keff|2
Relationship	φ	f = 0.001	f = 0.01
Identical twins	$\frac{1}{2}$	1.00	1.00
Parent–child	$\frac{1}{4}$	1.11	1.17
Sibs	$\frac{1}{4}$	1.11	1.17
Half-sibs	$\frac{1}{8}$	1.22	1.34
Uncle–nephew	$\frac{1}{8}$	1.22	1.34
First cousins	$\frac{1}{16}$	1.33	1.50
First cousins-1 (once removed)	$\frac{1}{32}$	1.44	1.64
Second cousins	$\frac{1}{64}$	1.55	1.76
Unrelateds	0	2.00	2.00

φ is the kinship coefficient. Results for two values of the frequency parameter f, 0.001 and 0.01, are shown.